Cisco IOS Configuration Fundamentals and Network Management Command Reference, Release 12.3
CFR Commands: absolute -- clock timezone

Table Of Contents

Configuration Fundamentals and Network Management Commands

absolute

activation-character

alias

alias (boomerang)

announce config

async-bootp

atm-slm statistics

attach

autobaud

banner exec

banner incoming

banner login

banner motd

banner slip-ppp

boot

boot bootldr

boot bootstrap

boot buffersize

boot config

boot host

boot network

boot system

boot-end-marker

boot-start-marker

buckets-of-history-kept

buffer-length

buffers

buffers element permanent

buffers huge size

calendar set

cd

cdp advertise-v2

cdp enable

cdp holdtime

cdp log mismatch duplex

cdp run

cdp source-interface

cdp timer

clear cdp counters

clear cdp table

clear cns config stats

clear cns counters

clear cns event stats

clear cns image connections

clear cns image status

clear logging

clear logging xml

clear parser cache

clear saa apm cache

clear tcp

clear xsm

cli

cli (cns)

clock calendar-valid

clock read-calendar

clock set

clock summer-time

clock timezone


Configuration Fundamentals and Network Management Commands


absolute

To specify an absolute time when a time range is in effect, use the absolute command in time-range configuration mode. To remove the time limitation, use the no form of this command.

absolute [start time date] [end time date]

no absolute

Syntax Description

start time date

(Optional) Absolute time and date that the permit or deny statement of the associated access list starts going into effect. The time is expressed in 24-hour notation, in the form of hours:minutes. For example, 8:00 is 8:00 a.m. and 20:00 is 8:00 p.m. The date is expressed in the format day month year. The minimum start is 00:00 1 January 1993. If no start time and date are specified, the permit or deny statement is in effect immediately.

end time date

(Optional) Absolute time and date that the permit or deny statement of the associated access list is no longer in effect. Same time and date format as described for the start keyword. The end time and date must be after the start time and date. The maximum end time is 23:59 31 December 2035. If no end time and date are specified, the associated permit or deny statement is in effect indefinitely.


Defaults

There is no absolute time when the time range is in effect.

Command Modes

Time-range configuration

Command History

Release
Modification

12.0(1)T

This command was introduced.


Usage Guidelines

Time ranges are used by IP and Internetwork Packet Exchange (IPX) extended access lists. For more information on using these functions, see the Cisco IOS IP Configuration Guide and the Cisco IOS AppleTalk and Novell IPX Configuration Guide. Time ranges are applied to the permit or deny statements found in these access lists.

The absolute command is one way to specify when a time range is in effect. Another way is to specify a periodic length of time with the periodic command. Use either of these commands after the time-range command, which enables time-range configuration mode and specifies a name for the time range. Only one absolute entry is allowed per time-range command.

If a time-range command has both absolute and periodic values specified, then the periodic items are evaluated only after the absolute start time is reached, and are not further evaluated after the absolute end time is reached.


Note All time specifications are interpreted as local time. To ensure that the time range entries take effect at the desired times, the software clock should be synchronized using the Network Time Protocol (NTP), or some other authoritative time source. For more information, refer to the "Performing Basic System Management" chapter of the Cisco IOS Configuration Fundamentals Configuration Guide.


Examples

The following example configures an access list named northeast, which references a time range named xyz. The access list and time range together permit traffic on Ethernet interface 0 starting at noon on January 1, 2001 and going forever.

time-range xyz
 absolute start 12:00 1 January 2001
!
ip access-list extended northeast
 permit ip any any time-range xyz
!
interface ethernet 0
 ip access-group northeast in

The following example permits UDP traffic until noon on December 31, 2000. After that time, UDP traffic is no longer allowed out Ethernet interface 0.

time-range abc
 absolute end 12:00 31 December 2000
!
ip access-list extended northeast
 permit udp any any time-range abc
!
interface ethernet 0
 ip access-group northeast out

The following example permits UDP traffic out Ethernet interface 0 on weekends only, from 8:00 a.m. on January 1, 1999 to 6:00 p.m. on December 31, 2001:

time-range test
 absolute start 8:00 1 January 1999 end 18:00 31 December 2001 
 periodic weekends 00:00 to 23:59
!
ip access-list extended northeast
 permit udp any any time-range test
!
interface ethernet 0
 ip access-group northeast out

Related Commands

Command
Description

deny

Sets conditions under which a packet does not pass a named access list.

periodic

Specifies a recurring (weekly) start and end time for a time range.

permit

Sets conditions under which a packet passes a named access list.

time-range

Enables time-range configuration mode and names a time range definition.


activation-character

To define the character you enter at a vacant terminal to begin a terminal session, use the activation-character command in line configuration mode. To make any character activate a terminal, use the no form of this command.

activation-character ascii-number

no activation-character

Syntax Description

ascii-number

Decimal representation of the activation character.


Defaults

Return (decimal 13)

Command Modes

Line configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

See the "ASCII Character Set and Hex Values" appendix for a list of ASCII characters.


Note If you are using the autoselect function, set the activation character to the default, Return, and exec-character-bits to 7. If you change these defaults, the application will not recognize the activation request.


Examples

The following example sets the activation character for the console to Delete, which is decimal character 127:

Router(config)# line console
Router(config-line)# activation-character 127

alias

To create a command alias, use the alias command in global configuration mode. To delete all aliases in a command mode or to delete a specific alias, and to revert to the original command syntax, use the no form of this command.

alias mode command-alias original-command

no alias mode [command-alias]

Syntax Description

mode

Command mode of the original and alias commands.

command-alias

Command alias.

original-command

Original command syntax.


Defaults

A set of six basic EXEC mode aliases are enabled by default. See the "Usage Guidelines" section of this command for a list of default aliases.

Command Modes

Global configuration

Command History

Release
Modification

10.3

This command was introduced.


Usage Guidelines

You can use simple words or abbreviations as command aliases.

Table 5 lists the basic EXEC mode aliases that are enabled by default.

Table 5 Default Command Aliases

Command Alias
Original Command

h

help

lo

logout

p

ping

r

resume

s

show

w

where


The default aliases in Table 5 are predefined. These default aliases can be disabled with the no alias exec command.

Common keyword aliases (which cannot be disabled) include running-config (keyword alias for system:running-config) and startup-config (keyword alias for nvram:startup-config). See the description of the copy command for more information about these keyword aliases.

Note that aliases can be configured for keywords instead of entire commands. You can create, for example, an alias for the first part of any command and still enter the additional keywords and arguments as normal.

To determine the value for the mode argument, enter the command mode in which you would issue the original command (and in which you will issue the alias) and enter the ? command. The name of the command mode should appear at the top of the list of commands. For example, the second line in the following sample output shows the name of the command mode as "Interface configuration":

Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# interface e0
Router(config-if)# ?
Interface configuration commands:
  access-expression       Build a bridge boolean access expression
 .
 .
 .

To match the name of the command mode to the acceptable mode keyword for the alias command, issue the alias ? command. As shown in the following sample output, the keyword needed to create a command alias for the access-expression command is interface:

Router(config)# alias ?
  accept-dialin          VPDN group accept dialin configuration mode
  accept-dialout         VPDN group accept dialout configuration mode
  address-family         Address Family configuration mode
  call-discriminator     Call Discriminator Configuration
  cascustom              Cas custom configuration mode
  clid-group             CLID group configuration mode
  configure              Global configuration mode
  congestion             Frame Relay congestion configuration mode
  controller             Controller configuration mode
  cptone-set             custom call progress tone configuration mode
  customer-profile       customer profile configuration mode
  dhcp                   DHCP pool configuration mode
  dnis-group             DNIS group configuration mode
  exec                   Exec mode
  flow-cache             Flow aggregation cache config mode
  fr-fr                  FR/FR connection configuration mode
  interface              Interface configuration mode
 .
 .
 .
Router(config)# alias interface express access-expression

For a list of command modes with descriptions and references to related documentation, refer to the "Cisco IOS Command Modes" appendix of the Cisco IOS Configuration Fundamentals Configuration Guide.

When you use online help, command aliases are indicated by an asterisk (*), and displayed in the following format:

*command-alias=original-command

For example, the lo command alias is shown here along with other EXEC mode commands that start with "lo":

Router# lo?
*lo=logout  lock  login  logout 

When you use online help, aliases that contain multiple keyword elements separated by spaces are displayed in quotes, as shown here:

Router(config)#alias exec device-mail telnet device.cisco.com 25
Router(config)#end
Router#device-mail?
*device-mail="telnet device.cisco.com 25" 

To list only commands and omit aliases, begin your input line with a space. In the following example, the alias td is not shown, because there is a space before the t? command line.

Router(config)#alias exec td telnet device
Router(config)#end
Router# t?
telnet terminal test tn3270 trace

To circumvent command aliases, use a space before entering the command. In the following example, the command alias express is not recognized because a space is used before the command.

Router(config-if)#exp?
*express=access-expression 
Router(config-if)# express ? 
% Unrecognized command 

As with commands, you can use online help to display the arguments and keywords that can follow a command alias. In the following example, the alias td is created to represent the command telnet device. The /debug and /line switches can be added to telnet device to modify the command:

Router(config)#alias exec td telnet device
Router(config)#end
Router#td ?
      /debug     Enable telnet debugging mode
      /line      Enable telnet line mode
      ...
      whois      Whois port
      <cr>
Router# telnet device 

You must enter the complete syntax for the command alias. Partial syntax for aliases is not accepted. In the following example, the parser does not recognize the command t as indicating the alias td:

Router# t 
% Ambiguous command: "t"

Examples

In the following example, the alias fixmyrt is configured for the clear iproute 192.168.116.16 EXEC mode command:

Router(config)#alias exec fixmyrt clear ip route 192.168.116.16

In the following example, the alias express is configured for the first part of the access-expression interface configuration command:

Router#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#interface e0
Router(config-if)#?
Interface configuration commands:
  access-expression        Build a bridge boolean access expression
  .
  .
  .

Router(config-if)#exit
Router(config)#alias ?
  accept-dialin         VPDN group accept dialin configuration mode
  accept-dialout        VPDN group accept dialout configuration mode
  address-family        Address Family configuration mode
  call-discriminator    Call Discriminator Configuration
  cascustom             Cas custom configuration mode
  clid-group            CLID group configuration mode
  configure             Global configuration mode
  congestion            Frame Relay congestion configuration mode
  controller            Controller configuration mode
  cptone-set            custom call progress tone configuration mode
  customer-profile      customer profile configuration mode
  dhcp                  DHCP pool configuration mode
  dnis-group            DNIS group configuration mode
  exec                  Exec mode
  flow-cache            Flow aggregation cache config mode
  fr-fr                 FR/FR connection configuration mode
  interface             Interface configuration mode
 .
 .
 .

Router(config)#alias interface express access-expression
Router(config)#int e0
Router(config-if)#exp?
*express=access-expression  

Router(config-if)#express ?
  input   Filter input packets
  output   Filter output packets

!Note that the true form of the command/keyword alias appears on the screen after issuing
!the express ? command.
Router(config-if)#access-expression ?
  input   Filter input packets
  output  Filter output packets
Router(config-if)#ex?
*express=access-expression  exit  

!Note that in the following line, a space is used before the ex? command
!so the alias is not displayed.
Router(config-if)# ex?
exit

!Note that in the following line, the alias cannot be recognized because
!a space is used before the command.
Router#(config-if)# express ?
% Unrecognized command

Router(config-if)# end 
Router# show alias interface
Interface configuration mode aliases:
  express               access-expression

Related Commands

Command
Description

show aliases

Displays command aliases.


alias (boomerang)

To configure an alias name for a specified domain, use the alias command in boomerang configuration mode. To remove this command from the configuration file and restore the system to its default condition with respect to this command, use the no form of this command.

alias alias-name

no alias alias-name

Syntax Description

alias-name

Alias name for a specified domain.


Defaults

No domain name alias is configured.

Command Modes

Boomerang configuration

Command History

Release
Modification

12.2(8)T

This command was introduced.


Usage Guidelines

The alias command can be used only on a Director Response Protocol (DRP) agent. The boomerang client is the DRP agent.

Use the alias command to specify one or more alias names for an existing domain. Because the boomerang client maintains separate counters for requests received for each domain name (alias or otherwise), use the show ip drp boomerang command to view these counters for a specified domain name and each of its aliases.

Examples

In the following example, the domain name alias is configured for www.boom1.com. The new alias for www.boom1.com is www.boom2.com:

Router(config)#  ip drp domain www.boom1.com
Router(config-boomerang)# alias www.boom2.com

Router# show running-config
.
.
.
ip drp domain www.boom1.com
alias www.boom2.com

Related Commands

Command
Description

ip drp domain

Adds a new domain to the DistributedDirector client or configures an existing domain and puts the client in boomerang configuration mode.

server (boomerang)

Configures the server address for a specified boomerang domain.

show ip drp

Displays DRP statistics on DistributedDirector or a DRP server agent.

show ip drp boomerang

Displays boomerang information on the DRP agent.

ttl dns

Configures the number of seconds for which an answer received from the boomerang client will be cached by the DNS client.

ttl ip

Configures the IP TTL value for the boomerang response packets sent from the boomerang client to the DNS client in number of hops.


announce config

To specify that an unsolicited configuration inventory is sent out by the CNS inventory agent at bootup, use the announce config command in CNS inventory configuration mode. To disable the sending of the configuration inventory, use the no form of this command.

announce config

no announce config

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command Modes

CNS inventory configuration

Command History

Release
Modification

12.3(1)

This command was introduced.


Usage Guidelines

Use this command to limit inventory requests by the CNS inventory agent. When configured, the routing device details will be announced on the CNS Event Bus, but the routing device will not respond to any queries from the CNS Event Bus.

Examples

The following example shows how to configure the CNS inventory agent to send out an unsolicited configuration inventory one time only at bootup:

Router(config)# cns inventory 
Router(cns_inv)# announce config 

Related Commands

Command
Description

cns inventory

Enables the CNS inventory agent and enters CNS inventory configuration mode.


async-bootp

To configure extended BOOTP requests for asynchronous interfaces as defined in RFC 1084, use the async-bootp command in global configuration mode. To restore the default, use the no form of this command.

async-bootp tag [:hostname] data

no async-bootp

Syntax Description

tag

Item being requested; expressed as filename, integer, or IP dotted decimal address. See Table 6 for possible keywords.

:hostname

(Optional) This entry applies only to the specified host. The :hostname argument accepts both an IP address and a logical host name.

data

List of IP addresses entered in dotted decimal notation or as logical host names, a number, or a quoted string.


Table 6 tag Keyword Options 

Keyword
Description

bootfile

Specifies use of a server boot file from which to download the boot program. Use the optional :hostname argument and the data argument to specify the filename.

subnet-mask mask

Dotted decimal address specifying the network and local subnetwork mask (as defined by RFC 950).

time-offset offset

Signed 32-bit integer specifying the time offset of the local subnetwork in seconds from Coordinated Universal Time (UTC).

gateway address

Dotted decimal address specifying the IP addresses of gateways for this subnetwork. A preferred gateway should be listed first.

time-server address

Dotted decimal address specifying the IP address of time servers (as defined by RFC 868).

IEN116-server address

Dotted decimal address specifying the IP address of name servers (as defined by IEN 116).

nbns-server address

Dotted decimal address specifying the IP address of Windows NT servers.

DNS-server address

Dotted decimal address specifying the IP address of domain name servers (as defined by RFC 1034).

log-server address

Dotted decimal address specifying the IP address of an MIT-LCS UDP log server.

quote-server address

Dotted decimal address specifying the IP address of Quote of the Day servers (as defined in RFC 865).

lpr-server address

Dotted decimal address specifying the IP address of Berkeley UNIX Version 4 BSD servers.

impress-server address

Dotted decimal address specifying the IP address of Impress network image servers.

rlp-server address

Dotted decimal address specifying the IP address of Resource Location Protocol (RLP) servers (as defined in RFC 887).

hostname name

The name of the client, which may or may not be domain qualified, depending upon the site.

bootfile-size value

A two-octet value specifying the number of 512-octet (byte) blocks in the default boot file.


Defaults

If no extended BOOTP commands are entered, the Cisco IOS software generates a gateway and subnet mask appropriate for the local network.

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

Use the show async-bootp EXEC command to list the configured parameters. Use the no async-bootp command to clear the list.

Examples

The following example illustrates how to specify different boot files: one for a PC, and one for a Macintosh. With this configuration, a BOOTP request from the host on 172.30.1.1 results in a reply listing the boot filename as pcboot. A BOOTP request from the host named "mac" results in a reply listing the boot filename as "macboot."

async-bootp bootfile :172.30.1.1 "pcboot"
async-bootp bootfile :mac "macboot"

The following example specifies a subnet mask of 255.255.0.0:

async-bootp subnet-mask 255.255.0.0

The following example specifies a negative time offset of the local subnetwork of 3600 seconds:

async-bootp time-offset -3600

The following example specifies the IP address of a time server:

async-bootp time-server 172.16.1.1

Related Commands

Command
Description

show async bootp

Displays the extended BOOTP request parameters that have been configured for asynchronous interfaces.


atm-slm statistics

To enable the Service Assurance Agent (SAA) ATM Service Level Monitoring (SLM) feature, use the atm-slm statistics command in global configuration mode. To disable ATM SLM, use the no form of this command.

atm-slm statistics

no atm-slm statistics

Syntax Description

This command has no arguments or keywords.

Defaults

ATM Service Level Monitoring is disabled.

Command Modes

Global configuration mode

Command History

Release
Modification

12.2(11)T

This command was introduced.


Usage Guidelines

To generate and retrieve performance statistics for ATM services using SAA, the ATM SLM feature must first be enabled on the device using the atm-slm statistics global configuration command. (Note that these performance statistics can be retrieved by other applications such as CNS or Visual Uptime.) If this command is not used, SAA SLM operations (type slm atm pvc, type slm atm interface, or type slm controller) cannot be configured on the system.

Disabling the ATM SLM feature with the no atm-slm statistics command will cause any currently configured SAA SLM operations to be removed from the configuration. When ATM SLM is disabled, no CNS/XML requests are processed.

Examples

In the following example, the ATM SLM feature is enabled before an SAA SLM operation is configured for ATM interface 0/1:

Router(config)# atm-slm statistics
Router(config)# rtr 1
Router(config-rtr)# type slm atm interface ATM0/1
Router(config-rtr-slm)# enhanced-history interval 900 buckets 100
Router(config-rtr-slm)# exit
Router(config)# rtr schedule 1 start-time now life forever

Related Commands

Command
Description

type slm atm pvc

Specifies that the operation is an SAA SLM ATM Circuit operation.

type slm atm interface

Specifies that the operation is an SAA SLM ATM Interface operation.

type slm controller

Specifies that the operation is an SAA SLM ATM or Frame Relay Controller operation.


attach

To connect to a specific line card for the purpose of executing monitoring and maintenance commands on that line card only, use the attach command in privileged EXEC mode. To exit from the Cisco IOS software image on the line card and return to the Cisco IOS image on the giabit route processor (GRP), use the exit command.

attach slot-number

Syntax Description

slot-number

Slot number of the line card you want to connect to. Slot numbers range from 0 to 11 for the Cisco 12012 router and 0 to 7 for the Cisco 12008 router. If the slot number is omitted, you are prompted for the slot number.


Defaults

No default behavior or values.

Command Modes

Privileged EXEC

Command History

Release
Modification

11.2 GS

This command was introduced for the Cisco 12000 series.


Usage Guidelines

You must first use the attach privileged EXEC command to access the Cisco IOS software image on a line card before using line card-specific show EXEC commands. Alternatively, you can use the execute-on privileged EXEC command to execute a show command on a specific line card.

After you connect to the Cisco IOS image on the line card using the attach command, the prompt changes to LC-Slotx#, where x is the slot number of the line card.

The commands executed on the line card use the Cisco IOS image on that line card.

You can also use the execute-on slot privileged EXEC command to execute commands on one or all line cards.


Note Do not execute the config EXEC command from the Cisco IOS software image on the line card.


Examples

In the following example, the user connects to the Cisco IOS image running on the line card in slot 9, gets a list of valid show commands, and returns the Cisco IOS image running on the GRP:

Router# attach 9

Entering Console for 4 Port Packet Over SONET OC-3c/STM-1 in Slot: 9
Type exit to end this session

Press RETURN to get started!

LC-Slot9# show ?

  cef       Cisco Express Forwarding
  clock     Display the system clock
  context   Show context information about recent crash(s)
  history   Display the session command history
  hosts     IP domain-name, lookup style, nameservers, and host table
  ipc       Interprocess communications commands
  location  Display the system location
  sessions  Information about Telnet connections
  terminal  Display terminal configuration parameters
  users     Display information about terminal lines
  version   System hardware and software status

LC-Slot9# exit

Disconnecting from slot 9.
Connection Duration: 00:01:04
Router# 

Note Because not all statistics are maintained on the line cards, the output from some of the show commands might not be consistent.


Related Commands

Command
Description

attach shelf

Connects you to a specific (managed) shelf for the purpose of remotely executing commands on that shelf only.

execute-on slot

Executes commands remotely on a specific line card, or on all line cards simultaneously.


autobaud

To set the line for automatic baud rate detection (autobaud), use the autobaud command in line configuration mode. To disable automatic baud detection, use the no form of this command.

autobaud

no autobaud

Syntax Description

This command has no arguments or keywords.

Defaults

Autobaud detection is disabled. Fixed speed of 9600 bps.

Command Modes

Line configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

The autobaud detection supports a range from 300 to 19200 baud. A line set for autobaud cannot be used for outgoing connections, nor can you set autobaud capability on a line using 19200 baud when the parity bit is set (because of hardware limitations).


Note Automatic baud rate detection must be disabled by using the no autobaud command prior to entering the rxspeed, speed, or txspeed commands.


Examples

In the following example, the auxiliary port is configured for autobaud detection:

Router(config)# line aux 
Router(config-line)# autobaud

banner exec

To specify and enable a message to be displayed when an EXEC process is created (an EXEC banner), use the banner exec command in global configuration mode. To delete the existing EXEC banner, use the no form of this command.

banner exec d message d

no banner exec

Syntax Description

d

Delimiting character of your choice—a pound sign (#), for example. You cannot use the delimiting character in the banner message.

message

Message text. You can include tokens in the form $(token) in the message text. Tokens will be replaced with the corresponding configuration variable. Tokens are described in Table 7.


Defaults

Disabled (no EXEC banner is displayed).

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.

11.3(7.5)AA

Token functionality was introduced.

12.0(3)T

Token functionality was integrated into Cisco IOS Release 12.0(3)T.


Usage Guidelines

This command specifies a message to be displayed when an EXEC process is created (a line is activated, or an incoming connection is made to a vty). Follow this command with one or more blank spaces and a delimiting character of your choice. Then enter one or more lines of text, terminating the message with the second occurrence of the delimiting character.

When a user connects to a router, the message-of-the-day (MOTD) banner appears first, followed by the login banner and prompts. After the user logs in to the router, the EXEC banner or incoming banner will be displayed, depending on the type of connection. For a reverse Telnet login, the incoming banner will be displayed. For all other connections, the router will display the EXEC banner.

To disable the EXEC banner on a particular line or lines, use the no exec-banner line configuration command.

To customize the banner, use tokens in the form $(token) in the message text. Tokens will display current Cisco IOS configuration variables, such as the router's host name and IP address. The tokens are described in Table 7.

Table 7 banner exec Tokens 

Token
Information Displayed in the Banner

$(hostname)

Displays the host name for the router.

$(domain)

Displays the domain name for the router.

$(line)

Displays the vty or tty (asynchronous) line number.

$(line-desc)

Displays the description attached to the line.


Examples

The following example sets an EXEC banner that uses tokens. The percent sign (%) is used as a delimiting character. Notice that the $(token) syntax is replaced by the corresponding configuration variable.

Router(config)# banner exec %
Enter TEXT message.  End with the character '%'.
Session activated on line $(line), $(line-desc). Enter commands at the prompt. 
% 

When a user logs on to the system, the following output is displayed:

User Access Verification

Username: joeuser
Password: <password>

 Session activated on line 50, vty default line. Enter commands at the prompt.

Router>

Related Commands

Command
Description

banner incoming

Defines a customized banner to be displayed when there is an incoming connection to a terminal line from a host on the network.

banner login

Defines a customized banner to be displayed before the username and password login prompts.

banner motd

Defines a customized message-of-the-day banner.

banner slip-ppp

Defines a customized banner to be displayed when a serial-line IP or point-to-point connection is made.

exec-banner

Controls (enables or disables) the display of EXEC banners and message-of-the-day banners on a specified line or lines.


banner incoming

To define and enable a banner to be displayed when there is an incoming connection to a terminal line from a host on the network, use the banner incoming command in global configuration mode. To delete the incoming connection banner, use the no form of this command.

banner incoming d message d

no banner incoming

Syntax Description

d

Delimiting character of your choice—a pound sign (#), for example. You cannot use the delimiting character in the banner message.

message

Message text. You can include tokens in the form $(token) in the message text. Tokens will be replaced with the corresponding configuration variable. Tokens are described in Table 8.


Defaults

Disabled (no incoming banner is displayed).

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.

11.3(7.5)AA

Token functionality was introduced.

12.0(3)T

Token functionality was integrated into Cisco IOS Release 12.0(3)T.


Usage Guidelines

Follow the banner incoming command with one or more blank spaces and a delimiting character of your choice. Then enter one or more lines of text, terminating the message with the second occurrence of the delimiting character.

An incoming connection is one initiated from the network side of the router. Incoming connections are also called reverse Telnet sessions. These sessions can display MOTD banners and incoming banners, but they do not display EXEC banners. Use the no motd-banner line configuration command to disable the MOTD banner for reverse Telnet sessions on asynchronous lines.

When a user connects to the router, the message-of-the-day (MOTD) banner (if configured) appears first, before the login prompt. After the user successfully logs in to the router, the EXEC banner or incoming banner will be displayed, depending on the type of connection. For a reverse Telnet login, the incoming banner will be displayed. For all other connections, the router will display the EXEC banner.

Incoming banners cannot be suppressed. If you do not want the incoming banner to appear, you must delete it with the no banner incoming command.

To customize the banner, use tokens in the form $(token) in the message text. Tokens will display current Cisco IOS configuration variables, such as the router's host name and IP address. The tokens are described in Table 8.

Table 8 banner incoming Tokens

Token
Information Displayed in the Banner

$(hostname)

Displays the host name for the router.

$(domain)

Displays the domain name for the router.

$(line)

Displays the vty or tty (asynchronous) line number.

$(line-desc)

Displays the description attached to the line.


Examples

The following example sets an incoming connection banner. The pound sign (#) is used as a delimiting character.

Router(config)# banner incoming #
This is the Reuses router.
#

The following example sets an incoming connection banner that uses several tokens. The percent sign (%) is used as a delimiting character.


darkstar(config)# banner incoming %
Enter TEXT message.  End with the character '%'.
You have entered $(hostname).$(domain) on line $(line) ($(line-desc)) %

When the incoming connection banner is executed, the user will see the following banner. Notice that the $(token) syntax is replaced by the corresponding configuration variable.

You have entered darkstar.ourdomain.com on line 5 (Dialin Modem)

Related Commands

Command
Description

banner exec

Defines a customized banner to be displayed whenever the EXEC process is initiated.

banner login

Defines a customized banner to be displayed before the username and password login prompts.

banner motd

Defines a customized message-of-the-day banner.

banner slip-ppp

Defines a customized banner to be displayed when a serial-line IP or point-to-point connection is made.


banner login

To define and enable a customized banner to be displayed before the username and password login prompts, use the banner login command in global configuration mode. To disable the login banner, use no form of this command.

banner login d message d

no banner login

Syntax Description

d

Delimiting character of your choice—a pound sign (#), for example. You cannot use the delimiting character in the banner message.

message

Message text. You can include tokens in the form $(token) in the message text. Tokens will be replaced with the corresponding configuration variable. Tokens are described in Table 9.


Defaults

Disabled (no login banner is displayed).

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.

11.3(7.5)AA

Token functionality was introduced.

12.0(3)T

Token functionality was integrated into Cisco IOS Release 12.0(3)T.


Usage Guidelines

Follow the banner login command with one or more blank spaces and a delimiting character of your choice. Then enter one or more lines of text, terminating the message with the second occurrence of the delimiting character.

When a user connects to the router, the message-of-the-day (MOTD) banner (if configured) appears first, followed by the login banner and prompts. After the user successfully logs in to the router, the EXEC banner or incoming banner will be displayed, depending on the type of connection. For a reverse Telnet login, the incoming banner will be displayed. For all other connections, the router will display the EXEC banner.

To customize the banner, use tokens in the form $(token) in the message text. Tokens will display current Cisco IOS configuration variables, such as the router's host name and IP address. The tokens are described in Table 9.

Table 9 banner login Tokens 

Token
Information Displayed in the Banner

$(hostname)

Displays the host name for the router.

$(domain)

Displays the domain name for the router.

$(line)

Displays the vty or tty (asynchronous) line number.

$(line-desc)

Displays the description attached to the line.


Examples

The following example sets a login banner. Double quotes (") are used as the delimiting character.

Router# banner login " Access for authorized users only. Please enter your username and 
password. "

The following example sets a login banner that uses several tokens. The percent sign (%) is used as the delimiting character.

darkstar(config)# banner login %
Enter TEXT message. End with the character '%'.
You have entered $(hostname).$(domain) on line $(line) ($(line-desc)) %

When the login banner is executed, the user will see the following banner. Notice that the $(token) syntax is replaced by the corresponding configuration variable.

You have entered darkstar.ourdomain.com on line 5 (Dialin Modem)

Related Commands

Command
Description

banner exec

Defines a customized banner to be displayed whenever the EXEC process is initiated.

banner incoming

Defines a customized message to be displayed when there is an incoming connection to a terminal line from a host on the network.

banner motd

Defines a customized message-of-the-day banner.

banner slip-ppp

Defines a customized banner to be displayed when a serial-line IP or point-to-point connection is made.


banner motd

To define and enable a message-of-the-day (MOTD) banner, use the banner motd command in global configuration mode. To delete the MOTD banner, use the no form of this command.

banner motd d message d

no banner motd

Syntax Description

d

Delimiting character of your choice—a pound sign (#), for example. You cannot use the delimiting character in the banner message.

message

Message text. You can include tokens in the form $(token) in the message text. Tokens will be replaced with the corresponding configuration variable.


Defaults

Disabled (no MOTD banner is displayed).

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.

11.3(7.5)AA

Token functionality was introduced.

12.0(3)T

Token functionality was integrated into Cisco IOS Release 12.0(3)T.


Usage Guidelines

Follow this command with one or more blank spaces and a delimiting character of your choice. Then enter one or more lines of text, terminating the message with the second occurrence of the delimiting character.

This MOTD banner is displayed to all terminals connected and is useful for sending messages that affect all users (such as impending system shutdowns). Use the no exec-banner or no motd-banner command to disable the MOTD banner on a line. The no exec-banner command also disables the EXEC banner on the line.

When a user connects to the router, the MOTD banner appears before the login prompt. After the user logs in to the router, the EXEC banner or incoming banner will be displayed, depending on the type of connection. For a reverse Telnet login, the incoming banner will be displayed. For all other connections, the router will display the EXEC banner.

To customize the banner, use tokens in the form $(token) in the message text. Tokens will display current Cisco IOS configuration variables, such as the router's host name and IP address. The tokens are described in Table 10.

Table 10 banner motd Tokens

Token
Information Displayed in the Banner

$(hostname)

Displays the host name for the router.

$(domain)

Displays the domain name for the router.

$(line)

Displays the vty or tty (asynchronous) line number.

$(line-desc)

Displays the description attached to the line.


Examples

The following example configures an MOTD banner. The pound sign (#) is used as a delimiting character.

Router# banner motd # Building power will be off from 7:00 AM until 9:00 AM this coming 
Tuesday. #

The following example configures an MOTD banner with a token. The percent sign (%) is used as a delimiting character.

darkstar(config)# banner motd %
Enter TEXT message.  End with the character '%'.
Notice: all routers in $(domain) will be upgraded beginning April 20
%

When the MOTD banner is executed, the user will see the following. Notice that the $(token) syntax is replaced by the corresponding configuration variable.

Notice: all routers in ourdomain.com will be upgraded beginning April 20

Related Commands

Command
Description

banner exec

Defines and enables a customized banner to be displayed whenever the EXEC process is initiated.

banner incoming

Defines and enables a customized message to be displayed when there is an incoming connection to a terminal line from a host on the network.

banner login

Defines and enables a customized banner to be displayed before the username and password login prompts.

banner slip-ppp

Defines and enables a customized banner to be displayed when a serial-line IP or point-to-point connection is made.

exec-banner

Controls (enables or disables) the display of EXEC banners and message-of-the-day banners on a specified line or lines.

motd-banner

Controls (enables or disables) the display of message-of-the-day banners on a specified line or lines.


banner slip-ppp

To customize the banner that is displayed when a Serial Line Internet Protocol (SLIP) or PPP connection is made, use the banner slip-ppp command in global configuration mode. To restore the default SLIP or PPP banner, use the no form of this command.

banner slip-ppp d message d

no banner slip-ppp

Syntax Description

d

Delimiting character of your choice—a pound sign (#), for example. You cannot use the delimiting character in the banner message.

message

Message text. You can include tokens in the form $(token) in the message text. Tokens will be replaced with the corresponding configuration variable.


Defaults

The default SLIP or PPP banner message is:

Entering encapsulation mode. 
Async interface address is unnumbered (Ethernet0) 
Your IP address is 10.000.0.0 MTU is 1500 bytes

The banner message when using the service old-slip-prompt command is:

Entering encapsulation mode.
Your IP address is 10.100.0.0 MTU is 1500 bytes

where encapsulation is SLIP or PPP.

Command Modes

Global configuration

Command History

Release
Modification

12.0(3)T

This command was introduced.


Usage Guidelines

Follow this command with one or more blank spaces and a delimiting character of your choice. Then enter one or more lines of text, terminating the message with the second occurrence of the delimiting character.

Use this command to define a custom SLIP or PPP connection message. This is useful when legacy client applications require a specialized connection string. To customize the banner, use tokens in the form $(token) in the message text. Tokens will display current Cisco IOS configuration variables, such as the routers host name, IP address, encapsulation type, and Maximum Transfer Unit (MTU) size. The banner tokens are described in Table 11.

Table 11 banner slip-ppp Tokens 

Token
Information Displayed in the Banner

$(hostname)

Displays the host name of the router.

$(domain)

Displays the domain name of the router.

$(peer-ip)

Displays the IP address of the peer machine.

$(gate-ip)

Displays the IP address of the gateway machine.

$(encap)

Displays the encapsulation type (SLIP, PPP, and so on).

$(encap-alt)

Displays the encapsulation type as SL/IP instead of SLIP.

$(mtu)

Displays the MTU size.


Examples

The following example sets the SLIP/PPP banner using several tokens and the percent sign (%) as the delimiting character:


Router(config)# banner slip-ppp %
Enter TEXT message.  End with the character '%'.
Starting $(encap) connection from $(gate-ip) to $(peer-ip) using a maximum packet size of 
$(mtu) bytes... %

The new SLIP/PPP banner will now be displayed when the slip EXEC command is used. Notice that the $(token) syntax is replaced by the corresponding configuration variable.


Router# slip
Starting SLIP connection from 172.16.69.96 to 192.168.1.200 using a maximum packet size of 
1500 bytes...

Related Commands

Command
Description

banner exec

Defines and enables a customized banner to be displayed whenever the EXEC process is initiated.

banner incoming

Defines and enables a customized message to be displayed when there is an incoming connection to a terminal line from a host on the network.

banner motd

Defines and enables a customized message-of-the-day banner.

ppp

Initiates a connection to a remote host using PPP.

slip

Initiates a connection to a remote host using SLIP.


boot

To boot the router manually, use the boot command in ROM monitor mode. The syntax of this command varies according to the platform and ROM monitor version.

boot

boot file-url

boot filename [tftp-ip-address]

boot flash [flash-fs:][partition-number:][filename]

Cisco 7000 Series, 7200 Series, 7500 Series Routers

boot flash-fs:[filename]

Cisco 1600 and Cisco 3600 Series Routers

boot [flash-fs:][partition-number:][filename]

Syntax Description

file-url

URL of the image to boot (for example, boot tftp://172.16.15.112/routertest).

filename

When used in conjunction with the ip-address argument, the filename argument is the name of the system image file to boot from a network server. The filename is case sensitive.

When used in conjunction with the flash keyword, the filename argument is the name of the system image file to boot from Flash memory.

On all platforms except the Cisco 1600 series, Cisco 3600 series, and Cisco 7000 family routers, the system obtains the image file from internal Flash memory.

On the Cisco 1600 series, Cisco 3600 series and Cisco 7000 family routers, the flash-fs: argument specifies the Flash memory device from which to obtain the system image. (See the flash-fs: argument later in this table for valid device values.) The filename is case sensitive. Without the filename argument, the first valid file in Flash memory is loaded.

tftp-ip-address

(optional) IP address of the TFTP server on which the system image resides. If omitted, this value defaults to the IP broadcast address of 255.255.255.255.

flash

Boots the router from Flash memory. Note that this keyword is required in some boot images.

flash-fs:

(Optional) Specifying the Flash file system is optional for all platforms except the Cisco 7500 series routers. Possible file systems are:

flash:—Internal Flash memory.

bootflash:—Internal Flash memory on the Cisco 7000 family.

slot0:—Flash memory card in the first PCMCIA slot on the Cisco 7000 family and Cisco 3600 series routers.

slot1:—Flash memory card in the second PCMCIA slot on the Cisco 7000 family and Cisco 3600 series routers.

partition-number:

(Optional) Specifies the partition number of the file system the file should be loaded from. This argument is not available on all platforms.


Defaults

For most platforms, if you enter the boot command and press Enter, the router boots from ROM by default. However, for some platforms, such as the Cisco 3600 series routers, if you enter the boot command and press Return, the router boots the first image in Flash memory. Refer to the documentation for your platform for information about the default image.

If the partition-number is not specified, the first partition is used.

If the filename is not specified, the first file in the partition or file system is used.

For other defaults, see the "Syntax Description" section.

Command Modes

ROM monitor

Command History

Release
Modification

10.3

The command was introduced.


Usage Guidelines

To determine which form of this command to use, refer to the documentation for your platform or use the CLI help (?) feature.

Use this command only when your router cannot find the boot configuration information needed in NVRAM. To enter ROM monitor mode, use one of the following methods:

Enter the reload EXEC command, then press the Break key during the first 60 seconds of startup.

Set the configuration register bits 0 to 3 to zero (for example, set the configuration register to 0x0) and enter the reload command.

The ROM Monitor prompt is either ">" or, for newer platforms, "rommon x>". Enter only lowercase commands.

These commands work only if there is a valid image to boot. Also, from the ROM monitor prompt, issuing a prior reset command is necessary for the boot to be consistently successful.

Refer to your hardware documentation for information on correct jumper settings for your platform.


Note For some platforms the flash keyword is now required. If your attempts to use the boot command are failing using the older boot flash:x:[filename] syntax, try using the boot flash flash:x:[filename] syntax.


Examples

In the following example, a router is manually booted from ROM:

> boot
F3:
(ROM Monitor copyrights)

In the following example, a router boots the file named routertest from a network server with the IP address 172.16.15.112 using the file-url syntax:

> boot tftp://172.16.15.112/routertest
F3
(ROM Monitor copyrights)

The following example shows the boot flash command without the filename argument. The first valid file in Flash memory is loaded.

> boot flash
F3: 1858656+45204+166896 at 0x1000
Booting gs7-k from flash memory RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR [OK - 1903912/13765276 bytes]
F3: 1858676+45204+166896 at 0x1000
(ROM Monitor copyrights)

The following example boots from Flash memory using the file named gs7-k:

> boot flash gs7-k
F3: 1858656+45204+166896 at 0x1000

Booting gs7-k from flash memory RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR
RRRRRRRRRRRRRR [OK - 1903912/13765276 bytes]
F3: 1858676+45204+166896 at 0x1000

(ROM Monitor copyrights)

In the following example, the boot flash flash: command boots the relocatable image file named igs-bpx-l from partition 2 in Flash memory:

> boot flash flash:2:igs-bpx-l
F3: 3562264+98228+303632 at 0x30000B4

(ROM Monitor copyrights)

In the following command, the Cisco 7000 family router accepts the flash keyword for compatibility but ignores it, and boots from slot 0:

> boot flash slot0:gs7-k-mz.103-9
F3: 8468+3980384+165008 at 0x1000

In the following example, the command did not function because it must be entered in lowercase:

rommon 10 > BOOT
command "BOOT" not found

The following example boots the first file in the first partition of internal Flash memory of a Cisco 3600 series router:

> boot flash:

The following example boots the first image file in the first partition of the Flash memory card in slot 0 of a Cisco 3600 series router:

> boot slot0:

The following example shows the ROM monitor booting the first file in the first Flash memory partition on a Cisco 1600 series router:

> boot flash:

Related Commands

Command
Description

continue

Returns to EXEC mode from ROM monitor mode by completing the boot process.


boot bootldr

To specify the location of the boot image that ROM uses for booting, use the boot bootldr command in global configuration mode. To remove this boot image specification, use the no form of this command.

boot bootldr file-url

no boot bootldr

Syntax Description

file-url

URL of the boot image on a Flash file system.


Defaults

Refer to your platform documentation for the location of the default boot image.

Command Modes

Global configuration

Command History

Release
Modification

11.0

The command was introduced.


Usage Guidelines

The boot bootldr command sets the BOOTLDR variable in the current running configuration. You must specify both the Flash file system and the filename.


Note When you use this global configuration command, you affect only the running configuration. You must save the variable setting to your startup configuration to place the information under ROM monitor control and to have the variable function as expected. Use the copy system:running-config nvram:startup-config command to save the variable from your running configuration to your startup configuration.


The no form of the command sets the BOOTLDR variable to a null string. On the Cisco 7000 family routers, a null string causes the first image file in boot Flash memory to be used as the boot image that ROM uses for booting.

Use the show boot command to display the current value for the BOOTLDR variable.

Examples

In the following example, the internal Flash memory contains the boot image:

boot bootldr bootflash:boot-image

The following example specifies that the Flash memory card inserted in slot 0 contains the boot image:

boot bootldr slot0:boot-image

Related Commands

Command
Description

copy system:running-config nvram:startup-config

Copies any file from a source to a destination.

show (flash file system)

Displays the layout and contents of a Flash memory file system.

show bootvar

Displays the contents of the BOOT variable, the name of the configuration file pointed to by the CONFIG_FILE variable, the contents of the BOOTLDR variable, and the configuration register setting.


boot bootstrap

To configure the filename that is used to boot a secondary bootstrap image, use the boot bootstrap command in global configuration mode. To disable booting from a secondary bootstrap image, use the no form of this command.

boot bootstrap file-url

no boot bootstrap file-url

boot bootstrap flash [filename]

no boot bootstrap flash [filename]

boot bootstrap [tftp] filename [ip-address]

no boot bootstrap [tftp] filename [ip-address]

Syntax Description

file-url

URL of the bootstrap image.

flash

Boots the router from Flash memory.

filename

(Optional with flash) Name of the system image to boot from a network server or from Flash memory. If you omit the filename when booting from Flash memory, the router uses the first system image stored in Flash memory.

tftp

(Optional) Boots the router from a system image stored on a TFTP server.

ip-address

(Optional) IP address of the TFTP server on which the system image resides. If omitted, this value defaults to the IP broadcast address of 255.255.255.255.


Defaults

No secondary bootstrap

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

The boot bootstrap command causes the router to load a secondary bootstrap image from the specied URL, such as from a remote server. After the bootstrap image is loaded, the bootstrap image loads the specified system image file. See the appropriate hardware installation guide for details on the setting the configuration register and secondary bootstrap filename.

Use this command when you have attempted to load a system image but have run out of memory even after compressing the system image. Secondary bootstrap images allows you to load a larger system image through a smaller secondary image.

Examples

In the following example, the system image file named sysimage-2 will be loaded by using a secondary bootstrap image:

Router(config)# boot bootstrap bootflash:sysimage-2 

boot buffersize

The boot buffersize global configuration command no longer functions.

Executing this command has no effect on the system. Using this command will not generate CLI errors; the boot buffersize command syntax is still allowed to be entered at the CLI and in configuration files in order to accommodate existing configuration scripts used by customers.

Command History

Release
Modification

10.0

This command was introduced.

12.1

Command functionality was removed.


boot config

To specify the device and filename of the configuration file from which the router configures itself during initialization (startup), use the boot config command in global configuration mode. This command is only available on Class A file system platforms. To remove the specification, use the no form of this command.

boot config file-system-prefix:[directory/]filename

no boot config

Syntax Description

file-system-prefix:

File system, followed by a colon (for example, nvram:, flash:, or slot0:).

directory/

(Optional) File system directory the configuration file is located in, followed by a forward slash (/).

filename

Name of the configuration file.


Defaults

NVRAM (nvram:)

Command Modes

Global configuration

Command History

Release
Modification

11.0

This command was introduced.


Usage Guidelines

This command is only available on Class A file system platforms.

You set the CONFIG_FILE environment variable in the current running memory when you use the boot config command. This variable specifies the configuration file used for initialization (startup). The configuration file must be an ASCII file located in either NVRAM or Flash memory.


Note When you use this global configuration command, you affect only the running configuration. You must save the environment variable setting to your startup configuration to place the information under ROM monitor control and to have the environment variable function as expected. Use the copy system:running-config nvram:startup-config command to save the environment variable from your running configuration to your startup configuration.


The software displays an error message and does not update the CONFIG_FILE environment variable in the following situations:

You specify nvram: as the file system, and it contains only a distilled version of the configuration. (A distilled configuration is one that does not contain access lists.)

You specify a configuration file in the filename argument that does not exist or is not valid.

The router uses the NVRAM configuration during initialization when the CONFIG_FILE environment variable does not exist or when it is null (such as at first-time startup). If the software detects a problem with NVRAM or the configuration it contains, the device enters setup mode. See the "Setup Command" chapter in this publication for more information on the setup command facility.

When you use the no form of this command, the router returns to using the default NVRAM configuration file as the startup configuration.

Examples

In the following example, the first line specifies that the router should use the configuration file named router-config located in internal Flash memory to configure itself during initialization. The third line copies the specification to the startup configuration, ensuring that this specification will take effect upon the next reload.

Router(config)# boot config flash:router-config
Router(config)# end
Router# copy system:running-config nvram:startup-config

The following example instructs a Cisco 7500 series router to use the configuration file named router-config located on the Flash memory card inserted in the second PCMCIA slot of the RSP card during initialization. The third line copies the specification to the startup configuration, ensuring that this specification will take effect upon the next reload.

Router (config)# boot config slot1:router-config
Router (config)# end
Router# copy system:running-config nvram:startup-config

Related Commands

Command
Description

show bootvar

Displays the contents of the BOOT environment variable, the name of the configuration file pointed to by the CONFIG_FILE environment variable, the contents of the BOOTLDR environment variable, and the configuration register setting.


boot host

To specify the host-specific configuration file to be used at the next system startup, use the boot host command in global configuration mode. To restore the host configuration filename to the default, use the no form of this command.

boot host remote-url

no boot host remote-url

Syntax Description

remote-url

Location of the configuration file. Use the following syntax:

ftp:[[[//[username[:password]@]location]/directory]/filename]

rcp:[[[//[username@]location]/directory]/filename]

tftp:[[[//location]/directory]/filename]


Defaults

If you do not specify a filename using this command, the router uses its configured host name to request a configuration file from a remote server. To form the configuration filename, the router converts its name to all lowercase letters, removes all domain information, and appends -confg or -config.

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

This command instructs the system to "Boot using host-specific configuration file x," where x is the filename specified in the remote-url argument. In other words, this command specifies the remote location and filename of the host-specific configuration file to be used at the next system startup, as well as the protocol to be used to obtain the file.

Before using the boot host command, use the service config global configuration command to enable the loading of the specified configuration file at reboot time. Without this command, the router ignores the boot host command and uses the configuration information in NVRAM. If the configuration information in NVRAM is invalid or missing, the service config command is enabled automatically.

The network server will attempt to load two configuration files from remote hosts. The first is the network configuration file containing commands that apply to all network servers on a network. Use the boot network command to identify the network configuration file. The second is the host configuration file containing commands that apply to one network server in particular. Use the boot host command to identify the host configuration file.


Note In releases prior to Cisco IOS Release 12.3(2)T and 12.3(1)B, the service config command is used in conjunction with the boot host or boot network command. To enable the router to automatically configure the system from the file specified by the boot host or boot network command you must enter the service config command.

With Cisco IOS Release 12.3(2)T , 12.3(1)B, and later, you no longer have to specify the service config command for the boot host or boot network command to be active.

If you specify both the no service config command and the boot host command, the router attempts to find the specified host configuration file.

The service config command can also be used without the boot host or boot network command. If you do not specify host or network configuration filenames, the router uses the default configuration files. The default network configuration file is network-confg. The default host configuration file is host-confg, where host is the hostname of the router. If the Cisco IOS software cannot resolve its hostname, the default host configuration file is router-confg.


Loading a Configuration File Using rcp

The rcp software requires that a client send the remote username on each rcp request to the network server. If the server has a directory structure (such as UNIX systems), the rcp implementation searches for the configuration files starting in the directory associated with the remote username.

When you load a configuration file from a server using rcp, the Cisco IOS software sends the first valid username in the following list:

1. The username specified in the file-URL, if a username is specified.

2. The username set by the ip rcmd remote-username command, if the command is configured.

3. The router host name.


Note An account for the username must be defined on the destination server. If the network administrator of the destination server did not establish an account for the username, this command will not execute successfully.


Loading a Configuration File Using FTP

The FTP protocol requires a client to send a remote username and password on each FTP request to a server. The username and password must be associated with an account on the FTP server. If the server has a directory structure, the configuration file or image copied from the directory is associated with the username on the server. Refer to the documentation for your FTP server for more details.

When you load a configuration file from a server using FTP, the Cisco IOS software sends the first valid username in the following list:

1. The username specified in the boot host command, if a username is specified.

2. The username set by the ip ftp username command, if the command is configured.

3. Anonymous.

The router sends the first valid password in the following list:

1. The password specified in the boot host command, if a password is specified.

2. The password set by the ip ftp password command, if the command is configured.

3. The router forms a password username@routername.domain. The variable username is the username associated with the current session, routername is the configured host name, and domain is the domain of the router.

Examples

The following example sets the host filename to wilma-confg at address 192.168.7.19:

Router(config)# boot host tftp://192.168.7.19/usr/local/tftpdir/wilma-confg
Router(config)# service config

Related Commands

Command
Description

boot network

Specifies the remote location and filename of the network configuration file to be used at the next system boot (startup).

service config

Enables autoloading of configuration files from a network server.


boot network

To change the default name of the network configuration file from which to load configuration commands, use the boot network command in global configuration mode. To restore the network configuration filename to the default, use the no form of this command.

boot network remote-url

no boot network remote-url

Syntax Description

remote-url

Location of the configuration file. Use the following syntax:

ftp:[[[//[username[:password]@]location]/directory]/filename]

rcp:[[[//[username@]location]/directory]/filename]

tftp:[[[//location]/directory]/filename]


Defaults

The default filename is network-config.

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

This command instructs the system to "Boot using network configuration file x," where x is the filename specified in the remote-url argument. This command specifies the remote location and filename of the network configuration file to be used at the next system startup, as well as the protocol to be used to obtain the file.

When booting from a network server, routers ignore routing information, static IP routes, and bridging information. As a result, intermediate routers are responsible for handling FTP, rcp, or TFTP requests. Before booting from a network server, verify that a server is available by using the ping command.

Use theservice config command to enable the loading of the specified configuration file at reboot time. Without this command, the router ignores the boot network command and uses the configuration information in NVRAM. If the configuration information in NVRAM is invalid or missing, the service config command is enabled automatically.

The network server will attempt to load two configuration files from remote hosts. The first is the network configuration file containing commands that apply to all network servers on a network. Use the boot network command to identify the network configuration file. The second is the host configuration file containing commands that apply to one network server in particular. Use the boot host command to identify the host configuration file.


Note In releases prior to Cisco IOS Release 12.3(2)T and 12.3(1)B, the service config command is used in conjunction with the boot host or boot network command. To enable the router to automatically configure the system from the file specified by the boot host or boot network command you must enter the service config command.

With Cisco IOS Release 12.3(2)T , 12.3(1)B, and later, you no longer have to specify the service config command for the boot host or boot network command to be active.

If you specify both the no service config command and the boot host command, the router attempts to find the specified host configuration file.

Theservice config command can also be used without the boot host or boot network command. If you do not specify host or network configuration filenames, the router uses the default configuration files. The default network configuration file is network-confg. The default host configuration file is host-confg, where host is the hostname of the router. If the Cisco IOS software cannot resolve its hostname, the default host configuration file is router-confg.


Loading a Configuration File Using rcp

The rcp software requires that a client send the remote username on each rcp request to the network server. If the server has a directory structure (such as UNIX systems), the rcp implementation searches for the configuration files starting in the directory associated with the remote username.

When you load a configuration file from a server using rcp, the Cisco IOS software sends the first valid username in the following list:

1. The username specified in the file-URL, if a username is specified.

2. The username set by the ip rcmd remote-username command, if the command is configured.

3. The router host name.


Note An account for the username must be defined on the destination server. If the network administrator of the destination server did not establish an account for the username, this command will not execute successfully.


Loading a Configuration File Using FTP

The FTP protocol requires a client to send a remote username and password on each FTP request to a server. The username and password must be associated with an account on the FTP server. If the server has a directory structure, the configuration file or image copied from the directory associated with the username on the server. Refer to the documentation for your FTP server for more details.

When you load a configuration file from a server using FTP, the Cisco IOS software sends the first valid username in the following list:

1. The username specified in the boot network command, if a username is specified.

2. The username set by the ip ftp username command, if the command is configured.

3. Anonymous.

The router sends the first valid password in the following list:

1. The password specified in the boot network command, if a password is specified.

2. The password set by the ip ftp password command, if the command is configured.

3. The router forms a password username@routername.domain. The variable username is the username associated with the current session, routername is the configured host name, and domain is the domain of the router.

Examples

The following example changes the network configuration filename to bridge_9.1 and uses the default broadcast address:

Router(config)# boot network tftp:bridge_9.1
Router(config)# service config

The following example changes the network configuration filename to bridge_9.1, specifies that rcp is to be used as the transport mechanism, and gives 172.16.1.111 as the IP address of the server on which the network configuration file resides:

Router(config)# service config
Router(config)# boot network rcp://172.16.1.111/bridge_9.1

Related Commands

Command
Description

boot host

Specifies the remote location and filename of the host-specific configuration file to be used at the next system boot (startup).

service config

Enables autoloading of configuration files from a remote host.


boot system

To specify the system image that the router loads at startup, use one of the following boot system commands in global configuration mode. To remove the startup system image specification, use the no form of this command.

boot system {file-url | filename}

no boot system {file-url | filename}

boot system flash [flash-fs:] [partition-number:] [filename]

no boot system flash [flash-fs:] [partition-number:] [filename]

boot system mop filename [mac-address] [interface]

no boot system mop filename [mac-address] [interface]

boot system rom

no boot system rom

boot system {rcp | tftp | ftp} filename [ip-address]

no boot system {rcp | tftp | ftp} filename [ip-address]

Syntax Description

file-url

Specifies the URL of the system image to load at system startup.

filename

Specifies the TFTP filename of the system image to load at system startup.

flash

On all platforms except the Cisco 1600 series, Cisco 3600 series, and Cisco 7000 family routers, this keyword boots the router from internal flash memory. If you omit all arguments that follow this keyword, the system searches internal flash for the first bootable image.

On the Cisco 1600 series, Cisco 3600 series, and Cisco 7000 family routers, this keyword boots the router from the flash file system specified by flash-fs. On the Cisco 1600 series and Cisco 3600 series routers, if you omit all optional arguments, the router searches internal flash memory for the first bootable image. On the Cisco 7000 family routers, when you omit all arguments that follow this keyword, the system searches the PCMCIA slot 0 for the first bootable image.

flash-fs:

(Optional) Flash file system containing the system image to load at startup. The colon is required. Valid file systems are as follows:

flash:—Internal flash memory on the Cisco 1600 series and Cisco 3600 series routers. For the Cisco 1600 series and Cisco 3600 series routers, this file system is the default if you do not specify a file system. This is the only valid file system for the Cisco 1600 series.

bootflash:—Internal flash memory in the Cisco 7000 family.

slot0:—First PCMCIA slot on the Cisco 3600 series and Cisco 7000 family routers. For the Cisco 7000 family routers, this file system is the default if you do not specify a file system.

slot1:—Flash memory card in the second PCMCIA slot on the Cisco 3600 series and Cisco 7000 family routers.

On the Cisco 2600 series routers, a file system should be specified. Otherwise, the router may attempt to load the Cisco IOS software twice with unexpected results.

partition-number:

(Optional) Number of the flash memory partition that contains the system image to boot, specified by the optional filename argument. If you do not specify a filename, the router loads the first valid file in the specified partition of flash memory. This argument is only valid on routers that can be partitioned.

filename

(Optional when used with the boot system flash command) Name of the system image to load at startup. This argument is case sensitive. If you do not specify a filename, the router loads the first valid file in the following:

The specified flash file system

The specified partition of flash memory

The default flash file system if you also omitted the flash-fs: argument.

mop

Boots the router from a system image stored on a Decnet Maintenance Operations Protocol (MOP) server. Do not use this keyword with the Cisco 3600 series or Cisco 7000 family routers.

mac-address

(Optional) MAC address of the MOP server containing the specified system image file. If you do not include the MAC address argument, the router sends a broadcast message to all MOP boot servers. The first MOP server to indicate that it has the specified file is the server from which the router gets the boot image.

interface

(Optional) Interface the router uses to send out MOP requests to the MOP server. The interface options are async, dialer, ethernet, serial, and tunnel. If you do not specify the interface argument, the router sends a request out on all interfaces that have MOP enabled. The interface that receives the first response is the interface the router uses to load the software.

rom

Boots the router from ROM. Do not use this keyword with the Cisco 3600 series or the Cisco 7000 family routers.

rcp

Boots the router from a system image stored on a network server using rcp.

tftp

Boots the router from a system image stored on a TFTP server.

ftp

Boots the router from a system image stored on an FTP server.

ip-address

(Optional) IP address of the server containing the system image file. If omitted, this value defaults to the IP broadcast address of 255.255.255.255.


Defaults

If you configure the router to boot from a network server but do not specify a system image file with the boot system command, the router uses the configuration register settings to determine the default system image filename. The router forms the default boot filename by starting with the word cisco and then appending the octal equivalent of the boot field number in the configuration register, followed by a hyphen (-) and the processor type name (cisconn-cpu). Refer to the appropriate hardware installation guide for details on the configuration register and default filename. See also the config-register or confreg command.

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.

12.2(14)SX

Support for this command was introduced on the Supervisor Engine 720.

12.2(17d)SXB

Support for this command on the Supervisor Engine 2 was extended to the Release 12.2(17d)SXB.


Usage Guidelines

For this command to work, the config-register command must be set properly.

Enter several boot system commands to provide a fail-safe method for booting your router. The router stores and executes the boot system commands in the order in which you enter them in the configuration file. If you enter multiple boot commands of the same type—for example, if you enter two commands that instruct the router to boot from different network servers—then the router tries them in the order in which they appear in the configuration file. If a boot system command entry in the list specifies an invalid device, the router omits that entry. Use the boot system rom command to specify use of the ROM system image as a backup to other boot commands in the configuration.

For some platforms, the boot image must be loaded before the system image is loaded. However, on many platforms, the boot image is loaded only if the router is booting from a network server or if the flash file system is not specified. If the file system is specified, the router will boot faster because it need not load the boot image first.

This section contains the following usage guideline topics:

Changing the List of Boot System Commands

Booting Compressed Images

Understanding rcp

Understanding TFTP

Understanding FTP

Stopping Booting and Enter ROM Monitor Mode

Cisco 1600 Series, Cisco 3600 Series, and Cisco 7000 Family Router Notes

Changing the List of Boot System Commands

To remove a single entry from the bootable image list, use the no form of the command with an argument. For example, to remove the entry that specifies a bootable image on a flash memory card inserted in the second slot, use the no boot system flash slot1:[filename] command. All other entries in the list remain.

To eliminate all entries in the bootable image list, use the no boot system command. At this point, you can redefine the list of bootable images using the previous boot system commands. Remember to save your changes to your startup configuration by issuing the copy system:running-config nvram:startup-config command.

Each time you write a new software image to flash memory, you must delete the existing filename in the configuration file with the no boot system flash filename command. Then add a new line in the configuration file with the boot system flash filename command.


Note If you want to rearrange the order of the entries in the configuration file, you must first issue the no boot system command and then redefine the list.


Booting Compressed Images

You can boot the router from a compressed image on a network server. When a network server boots software, both the image being booted and the running image must fit into memory. Use compressed images to ensure that enough memory is available to boot the router. You can compress a software image on any UNIX platform using the compress command. Refer to your UNIX platform's documentation for the exact usage of the compress command. (You can also uncompress data with the UNIX uncompress command.)

Understanding rcp

The rcp requires that a client send the remote username in an rcp request to a server. When the router executes the boot system rcp command, the Cisco IOS software sends the hostname as both the remote and local usernames by default. For the rcp to execute properly, an account must be defined on the network server for the remote username configured on the router.

If the server has a directory structure, the rcp software searches for the system image to boot from the remote server relative to the directory of the remote username.

By default, the router software sends hostname as the remote username. You can override the default remote username by using the ip rcmd remote-username command. For example, if the system image resides in the home directory of a user on the server, you can specify that user's name as the remote username.

Understanding TFTP

You need a TFTP server running in order to retrieve the router image from the host.

Understanding FTP

You need to an FTP server running in order to fetch the router image from the host. You also need an account on the server or anonymous file access to the server.

Stopping Booting and Entering ROM Monitor Mode

During the first 60 seconds of startup, you can force the router to stop booting by pressing the Break key. The router will enter ROM Monitor mode, where you can change the configuration register value or boot the router manually.

Cisco 1600 Series, Cisco 3600 Series, and Cisco 7000 Family Router Notes

For the Cisco 3600 series and Cisco 7000 family, the boot system command modifies the BOOT variable in the running configuration. The BOOT variable specifies a list of bootable images on various devices.


Note When you use the boot system command on the Cisco 1600 series, Cisco 3600 series, and Cisco 7000 family, you affect only the running configuration. You must save the BOOT variable settings to your startup configuration to place the information under ROM monitor control and to have the variable function as expected. Use the copy system:running-config nvram:startup-config privileged EXEC command to save the variable from your running configuration to your startup configuration.


To view the contents of the BOOT variable, use the show bootenv privileged EXEC command.

Examples

The following example illustrates a configuration that specifies two possible internetwork locations for a system image, with the ROM software being used as a backup:

Router(config)# boot system tftp://192.168.7.24/cs3-rx.90-1 
Router(config)# boot system tftp://192.168.7.19/cs3-rx.83-2 
Router(config)# boot system rom 

The following example boots the system boot relocatable image file named igs-bpx-l from partition 2 of the flash device:

Router(config)# boot system flash:2:igs-bpx-l 

The following example instructs the router to boot from an image located on the flash memory card inserted in slot 0:

Router(config)# boot system slot0:new-config 

The following example specifies the file named new-ios-image as the system image for a Cisco 3600 series router to load at startup. This file is located in the fourth partition of the flash memory card in slot 0.

Router(config)# boot system slot0:4:dirt/images/new-ios-image

This example boots from the image file named c1600-y-l in partition 2 of flash memory of a Cisco 1600 series router:

Router(config)# boot system flash:2:c1600-y-l

Related Commands

Command
Description

config-register

Changes the configuration register settings.

copy

Copies any file from a source to a destination.

ip rcmd remote username

Configures the remote username to be used when requesting a remote copy using rcp.

show bootvar

Displays the contents of the BOOT variable, the name of the configuration file pointed to by the CONFIG_FILE variable, the contents of the BOOTLDR variable, and the configuration register setting.


boot-end-marker

The boot-start-marker and boot-end-marker flags, which can be seen in Cisco IOS software configuration files, are not CLI commands. These markers are written to configuration files automatically to flag the beginning and end of the boot commands (boot statements). By flagging boot statements, these markers allow the router to more reliably load Cisco IOS images during bootup.

A boot statement is one or more lines in a configuration file that tells the router which software image to load after a powercycling (reboot). The boot-start-marker and boot-end-marker flags will appear around any boot commands, including:

boot bootstrap

boot config

boot host

boot network

boot system

Note, however, that these markers will always appear in the output of the show running-config or more system:running-config commands, regardless of whether any actual boot commands have been entered. This means that no boot commands will appear between the markers if no boot commands have been entered, or if all boot commands have been removed from the configuration, as shown in the "Examples" section.

The boot-start-marker and boot-end-marker flags cannot be removed or modified using the CLI. These markers are written to the startup configuration file whenever a copy running-config startup-config command is issued.

These flags were also introduced to circumvent errors in the configuration file, such as a leading space before a boot command (such as those sometimes introduced by manually edited configuration files), or the use of text strings that include the word "boot" in banners or other user-specified text.

If the "boot start-marker" flag is not found in the configuration file, the system will use the traditional method to identify the boot commands. However, if you are manually creating configuration files, or copying from older Cisco IOS software releases, the addition of these markers is recommended.

Command History

Release
Modification

12.3(3), 12.3(4)T, 12.0(26)S, 12.0(27)SV, 12.3(3)B,

The boot-start-marker and boot-end-marker flags were introduced.


Examples

In the following example, a boot command is entered, and the boot-start-marker and boot-end-marker flags are shown in the context of the startup configuration file:

Router# configure terminal 
Enter configuration commands, one per line.  End with the end command. 

Router(config)# boot system slot0: 
Router(config)# end 
Router# copy running-config startup-config
Router# show startup-config

Using 1398 out of 129016 bytes
!
version 12.3
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname C3660-2
!
boot-start-marker
boot system slot0:
boot-end-marker
!
logging count
 .
 .
 .

In the following example, the boot-start-marker and boot-end-marker flags appear in the configuration file even though no boot commands have been entered:

Router# show running-configuration 

Current configuration :3055 bytes
!
! No configuration change since last restart
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
 .
 .
 .

Related Commands

Command
Description

boot bootstrap

Specifies the filename and location of a secondary bootstrap image (to be used if a valid software image cannot be loaded).

boot config

Specifies the device and filename of the configuration file from which the router boots during startup (for Class A filesytems).

boot host

Specifies a remote host location for the host-specific (router-specific) configuration file to be used at the next system startup.

boot network

Specifies a remote location for the network (network-wide) configuration file to be used at the next system startup.

boot system

Specifies the system software image that the router loads at startup.


boot-start-marker

The boot-start-marker and boot-end-marker flags, which can be seen in Cisco IOS software configuration files, are not CLI commands. These markers are written to configuration files automatically to flag the beginning and end of the boot commands (boot statements). By flagging boot statements, these markers allow the router to more reliably load Cisco IOS images during bootup.

A boot statement is one or more lines in a configuration file that tells the router which software image to load after a powercycling (reboot). The boot-start-marker and boot-end-marker flags will appear around any boot commands, including:

boot bootstrap

boot config

boot host

boot network

boot system

Note, however, that these markers will always appear in the output of the show running-config or more system:running-config commands, regardless of whether any actual boot commands have been entered. This means that no boot commands will appear between the markers if no boot commands have been entered, or if all boot commands have been removed from the configuration, as shown in the "Examples" section.

The boot-start-marker and boot-end-marker flags cannot be removed or modified using the CLI. These markers are written to the startup configuration file whenever a copy running-config startup-config command is issued.

These flags were also introduced to circumvent errors in the configuration file, such as a leading space before a boot command (such as those sometimes introduced by manually edited configuration files), or the use of text strings that include the word "boot" in banners or other user-specified text.

If the "boot start-marker" flag is not found in the configuration file, the system will use the traditional method to identify the boot commands. However, if you are manually creating configuration files, or copying from older Cisco IOS software releases, the addition of these markers is recommended.

Command History

Release
Modification

12.3(3), 12.3(4)T, 12.0(26)S, 12.0(27)SV, 12.3(3)B

The boot-start-marker and boot-end-marker flags were introduced.


Examples

In the following example, a boot command is entered, and the boot-start-marker and boot-end-marker flags are shown in the context of the startup configuration file:

Router# configure terminal 
Enter configuration commands, one per line.  End with the end command. 

Router(config)# boot system slot0: 
Router(config)# end 
Router# copy running-config startup-config
Router# show startup-config

Using 1398 out of 129016 bytes
!
version 12.3
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname C3660-2
!
boot-start-marker
boot system slot0:
boot-end-marker
!
logging count
 .
 .
 .

In the following example, the boot-start-marker and boot-end-marker flags appear in the configuration file even though no boot commands have been entered:

Router# show running-configuration 

Current configuration :3055 bytes
!
! No configuration change since last restart
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
 .
 .
 .

Related Commands

Command
Description

boot bootstrap

Specifies the filename and location of a secondary bootstrap image (to be used if a valid software image cannot be loaded).

boot config

Specifies the device and filename of the configuration file from which the router boots during startup (for Class A filesytems).

boot host

Specifies a remote host location for the host-specific (router-specific) configuration file to be used at the next system startup.

boot network

Specifies a remote location for the network (network-wide) configuration file to be used at the next system startup.

boot system

Specifies the system software image that the router loads at startup.


buckets-of-history-kept

To set the number of history buckets that are kept during a Service Assurance Agent (SAA) operation's lifetime, use the buckets-of-history-kept command in SAA RTR configuration mode. To return to the default value, use the no form of this command.

buckets-of-history-kept size

no buckets-of-history-kept

Syntax Description

size

Number of history buckets kept during the lifetime of the operation. The default is 50 buckets.


Defaults

50 buckets

Command Modes

SAA RTR configuration

Command History

Release
Modification

11.2

This command was introduced.


Usage Guidelines

History collection and statistics capturing is enabled for the following SAA operations: ICMP Echo, SNA Echo, ICMP PathEcho, UDP Echo, TcpConnect, DNS, and DLSW. History collection is not supported for HTTP and Jitter (UDP+) operations.

By default, history is not collected. When a problem arises where history is useful (for example, a large number of timeouts are occurring), you can configure the lives-of-history-kept SAA RTR configuration command to collect history. You can optionally adjust the buckets-of-history-kept, filter-for-history, and samples-of-history-kept SAA RTR configuration commands.

When the number of buckets reaches the size specified, no further history for this life is stored.


Note Collecting history increases the RAM usage. Only collect history when you think there is a problem in the network. For general network response time information, use the statistics gathering feature of SAA.


If history is collected, each bucket contains one or more history entries from the operation. When the operation type is pathEcho, an entry is created for each hop along the path that the operation takes to reach its destination. The type of entry stored in the history table is controlled by the filter-for-history SAA RTR configuration command. The total number of entries stored in the history table is controlled by the combination of samples-of-history-kept, buckets-of-history-kept, and lives-of-history-kept SAA RTR configuration commands.

Each time the SAA starts an operation, a new bucket is created until the number of history buckets matches the specified size or the operation's lifetime expires. History buckets do not wrap. The operation's lifetime is defined by the rtr schedule global configuration command. The operation starts an SAA operation based on the seconds specified by the frequency SAA RTR configuration command.

Examples

The following example configures operation 1 to keep 25 history buckets during the operation lifetime:

Router(config)# rtr 1
Router(config-rtr)# type echo protocol ipIcmpEcho 172.16.161.21
Router(config-rtr)# buckets-of-history-kept 25
Router(config-rtr)# lives-of-history-kept 1

Related Commands

Command
Description

filter-for-history

Defines the type of information kept in the history table for the SA Agent operation.

lives-of-history-kept

Sets the number of lives maintained in the history table for the SA Agent operation.

rtr

Specifies an SAA operation and enters SAA RTR configuration mode.

rtr schedule

Configures the time parameters for an SAA operation.

samples-of-history-kept

Sets the number of entries kept in the history table per bucket for the SA Agent operation.


buffer-length

To specify the maximum length of the data stream to be forwarded, use the buffer-length command in line configuration mode. To restore the default setting, use the no form of this command.

buffer-length length

no buffer-length

Syntax Description

length

Specifies the length of the buffer in bytes. Valid values for the length argument range from 16 to 1536. The default buffer length is 1536 bytes.


Defaults

1536 bytes

Command Modes

Line configuration

Command History

Release
Modification

12.1

This command was introduced.


Usage Guidelines

The buffer-length command configures the size of the forwarded data stream. The higher the value used for the length argument is, the longer the delay between data transmissions will be. Configuring a smaller buffer length can prevent connections from timing out inappropriately.

Examples

The following example configures a buffer length of 500 bytes:

Router(config)# line 1 
Router(config-line)# buffer-length 500 

buffers

To make adjustments to initial buffer pool settings and to the limits at which temporary buffers are created and destroyed, use the buffers command in global configuration mode. To return the buffers to their default size, use the no form of this command.

buffers {small | middle | big | verybig | large | huge | type number} {permanent | max-free | min-free | initial} number-of-buffers

no buffers {small | middle | big | verybig | large | huge | type number} {permanent | max-free | min-free | initial} number-of-buffers

Syntax Description

small

Buffer size of this public buffer pool is 104 bytes.

middle

Buffer size of this public buffer pool is 600 bytes.

big

Buffer size of this public buffer pool is 1524 bytes.

verybig

Buffer size of this public buffer pool is 4520 bytes.

large

Buffer size of this public buffer pool is 5024 bytes.

huge

Default buffer size of this public buffer pool is 18024 bytes. This value can be configured with the buffers huge size command.

type number

Interface type and interface number of the interface buffer pool. The type value cannot be fddi.

permanent

Number of permanent buffers that the system tries to create and keep. Permanent buffers are normally not trimmed by the system.

max-free

Maximum number of free or unallocated buffers in a buffer pool. A maximum of 20,480 small buffers can be constructed in the pool.

min-free

Minimum number of free or unallocated buffers in a buffer pool.

initial

Number of additional temporary buffers that are to be allocated when the system is reloaded. This keyword can be used to ensure that the system has necessary buffers immediately after reloading in a high-traffic environment.

number-of-buffers

Number of buffers to be allocated.


Defaults

The default number of buffers in a pool is determined by the hardware configuration and can be displayed with the show buffers EXEC command.

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

Normally you need not adjust these parameters; do so only after consulting with technical support personnel.


Note Improper buffer settings can adversely impact system performance.


You cannot configure FDDI buffers.

Examples

Examples of Public Buffer Pool Tuning

The following example keeps at least 50 small buffers free in the system:

Router(config)# buffers small min-free 50

The following example increases the permanent buffer pool allocation for big buffers to 200:

Router(config)# buffers big permanent 200

Example of Interface Buffer Pool Tuning

A general guideline is to display buffers with the show buffers command, observe which buffer pool is depleted, and increase that one.

The following example increases the permanent Ethernet interface 0 buffer pool on a Cisco 4000 router to 96 when the Ethernet 0 buffer pool is depleted:

Router(config)# buffers ethernet 0 permanent 96

Related Commands

Command
Description

load-interval

Changes the length of time for which data is used to compute load statistics.

show buffers

Displays statistics for the buffer pools on the network server.


buffers element permanent

To configure the number of permanent buffer elements to prevent packet drop, use the buffers element permanent command in global configuration mode. To reset the number of permanent buffer elements to the default value, use the no form of this command.

buffers element permanent elements

no buffers element permanent

Syntax Description

elements

Number of permanent buffer elements. The range is from 500 to 65535. The default is 500.


Defaults

The default number of permanent buffer elements is 500.

Command Modes

Global configuration

Command History

Release
Modification

12.3(17)

This command was introduced.


Usage Guidelines

Use the buffers element permanent command to increase the number of permanent buffer elements to prevent packet drop. For example, in a multicasting environment, a higher number of buffer elements may be needed to accommodate bursts of traffic.


Note Using the buffers element permanent command during system initialization is always preferable because a higher number of permanent buffer elements will then be ready for use in case a burst of traffic occurs.


Use the show buffers command to display statistics such as free list (the total number of currently unallocated buffer elements), max allowed (the maximum number of buffer elements that are available for allocation), hits (the count of successful attempts to allocate a buffer when needed), misses (the count of buffer allocation attempts that resulted in growing the buffer pool to allocate a buffer), and created (the count of new buffers created to satisfy buffer allocation attempts when the available buffers in the pool have already been allocated).


Note If the requested number of permanent buffer elements is fewer than the current number of permanent buffer elements, the configuration will not take effect until the next reload. Resetting the number of permanent buffer elements to the default value using the no form of this command will not take effect until the next reload.


Examples

The following example configures the number of permanent buffer elements to 6000:

Router(config)# buffers element permanent 6000

Related Commands

Command
Description

show buffers

Displays statistics for the buffer pools on the network server.


buffers huge size

To dynamically resize all huge buffers to the value you specify, use the buffers huge size command in global configuration mode. To restore the default buffer values, use the no form of this command.

buffers huge size number-of-bytes

no buffers huge size number-of-bytes

Syntax Description

number-of-bytes

Huge buffer size (in bytes). Valid range is from 18024 to 100000 bytes.


Defaults

18,024 bytes

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

Use this command only after consulting with technical support personnel. The buffer size cannot be lowered below the default.


Note Improper buffer settings can adversely impact system performance.


Examples

The following example resizes huge buffers to 20,000 bytes:

Router(config)# buffers huge size 20000

Related Commands

Command
Description

buffers

Adjusts the initial buffer pool settings and the limits at which temporary buffers are created and destroyed.

show buffers

Displays statistics for the buffer pools on the network server.


calendar set

To manually set the hardware clock (calendar), use one of the formats of the calendar set command in EXEC mode.

calendar set hh:mm:ss day month year

calendar set hh:mm:ss month day year

Syntax Description

hh:mm:ss

Current time in hours (using 24-hour notation), minutes, and seconds.

day

Current day (by date) in the month.

month

Current month (by name).

year

Current year (no abbreviation).


Command Modes

EXEC

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

Some platforms have a hardware clock that is separate from the software clock. In Cisco IOS software syntax, the hardware clock is called the "calendar." The hardware clock is a battery-powered chip that runs continuously, even if the router is powered off or rebooted. After you set the hardware clock, the software clock will be automatically set from the hardware clock when the system is restarted or when the clock read-calendar EXEC command is issued. The time specified in this command is relative to the configured time zone.

Examples

The following example manually sets the hardware clock to 1:32 p.m. on May 19, 2003:

Router# calendar set 13:32:00 May 19 2003

Related Commands

Command
Description

clock read-calendar

Performs a one-time update of the software clock from the hardware clock (calendar).

clock set

Sets the software clock.

clock summer-time

Configures the system time to automatically switch to summer time (daylight saving time).

clock timezone

Sets the time zone for display purposes.

clock update-calendar

Performs a one-time update of the hardware clock from the software clock.


cd

To change the default directory or file system, use the cd command in EXEC mode.

cd [filesystem:]

Syntax Description

filesystem:

(Optional) The URL or alias of the directory or file systems followed by a colon.


Defaults

The initial default file system is flash:. For platforms that do not have a physical device named flash:, the keyword flash: is aliased to the default Flash device.

If you do not specify a directory on a file system, the default is the root directory on that file system.

Command Modes

EXEC

Command History

Release
Modification

11.0

This command was introduced.


Usage Guidelines

For all EXEC commands that have an optional filesystem argument, the system uses the file system specified by the cd command when you omit the optional filesystem argument. For example, the dir EXEC command, which displays a list of files on a file system, contain an optional filesystem argument. When you omit this argument, the system lists the files on the file system specified by the cd command.

Examples

In the following example, the cd command is used to set the default file system to the Flash memory card inserted in slot 0:

Router# pwd 
bootflash:/
Router# cd slot0: 
Router# pwd 
slot0:/

Related Commands

Command
Description

copy

Copies any file from a source to a destination.

delete

Deletes a file on a Flash memory device.

dir

Displays a list of files on a file system.

pwd

Displays the current setting of the cd command.

show file systems

Lists available file systems and their alias prefix names.

undelete

Recovers a file marked "deleted" on a Class A or Class B Flash file system.


cdp advertise-v2

To enable Cisco Discovery Protocol Version 2 (CDPv2) advertising functionality on a device, use the cdp advertise-v2 command in global configuration mode. To disable advertising CDPv2 functionality, use the no form of the command.

cdp advertise-v2

no cdp advertise-v2

Syntax Description

This command has no arguments or keywords.

Defaults

Enabled

Command Modes

Global configuration

Command History

Release
Modification

12.0(3)T

This command was introduced.


Usage Guidelines

CDP Version 2 has three additional type-length values (TLVs): VTP Management Domain Name, Native VLAN, and full/half-Duplex.

Examples

In the following example, CDP Version 2 advertisements are disabled on the router:

Router# show cdp
Global CDP information:
        Sending CDP packets every 60 seconds
        Sending a holdtime value of 180 seconds
        Sending CDPv2 advertisements is  enabled
Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# no cdp advertise-v2
Router(config)# end
Router# show cdp
Global CDP information:
        Sending CDP packets every 60 seconds
        Sending a holdtime value of 180 seconds
        Sending CDPv2 advertisements is not enabled
Router#

Related Commands

Command
Description

cdp enable

Enables CDP on a supported interface.

cdp run

Reenables CDP on a Cisco device.


cdp enable

To enable Cisco Discovery Protocol (CDP) on an interface, use the cdp enable command in interface configuration mode. To disable CDP on an interface, use the no form of this command.

cdp enable

no cdp enable

Syntax Description

This command has no arguments or keywords.

Defaults

Enabled at the global level and on all supported interfaces.

Command Modes

Interface configuration

Command History

Release
Modification

10.3

This command was introduced.


Usage Guidelines

CDP is enabled by default at the global level and on each supported interface in order to send or receive CDP information. However, some interfaces, such as ATM interfaces, do not support CDP.


Note The cdp enable, cdp timer, and cdp run commands affect the operation of the IP on demand routing feature (that is, the router odr global configuration command). For more information on the router odr command, see the "On-Demand Routing Commands"  chapter in the Cisco IOS IP Command Reference, Volume 2 of 3: Routing Protocols document.


Examples

In the following example, CDP is disabled on the Ethernet 0 interface only:

Router# show cdp
Global CDP information:
        Sending CDP packets every 60 seconds
        Sending a holdtime value of 180 seconds
        Sending CDPv2 advertisements is  enabled
Router# config terminal
Router(config)# interface ethernet 0
Router(config-if)# no cdp enable

Related Commands

Command
Description

cdp run

Reenables CDP on a Cisco device.

cdp timer

Specifies how often the Cisco IOS software sends CDP updates.

router odr

Enables on-demand routing on a hub router.


cdp holdtime

To specify the amount of time the receiving device should hold a Cisco Discovery Protocol (CDP) packet from the router before discarding it, use the cdp holdtime command in global configuration mode. To revert to the default setting, use the no form of this command.

cdp holdtime seconds

no cdp holdtime

Syntax Description

seconds

Specifies the hold time to be sent in the CDP update packets. The default is 180 seconds.


Defaults

180 seconds

Command Modes

Global configuration

Command History

Release
Modification

10.3

This command was introduced.


Usage Guidelines

CDP packets are sent with a time to live, or hold time, value. The receiving device will discard the CDP information in the CDP packet after the hold time has elapsed.

You can set the hold time lower than the default setting of 180 seconds if you want the receiving devices to update their CDP information more rapidly.

The CDP hold time must be set to a higher number of seconds than the time between CDP transmissions, which is set using the cdp timer command.

Examples

In the following example, the CDP packets being sent from the router are configured with a hold time of 60 seconds.

Router(config)# cdp holdtime 60

Related Commands

Command
Description

cdp timer

Specifies how often the Cisco IOS software sends CDP updates.

show cdp

Displays global CDP information, including timer and hold-time information.


cdp log mismatch duplex

To display the log of duplex mismatches generated by the Cisco Discovery Protocol (CDP) on Ethernet interfaces on a router, use the cdp log mismatch duplex command in global configuration or interface configuration mode. To disable the display of duplex messages on all Ethernet interfaces, use the no form of this command.

cdp log mismatch duplex

no cdp log mismatch duplex

Syntax Description

This command has no arguments or keywords.

Defaults

The router reports duplex mismatches from all Ethernet interfaces.

Command Modes

Global configuration
Interface configuration

Command History

Release
Modification

12.0

This command was introduced.


Usage Guidelines

When you enter the cdp log mismatch duplex command in global configuration mode, duplex mismatches are displayed on all Ethernet interfaces on the router. When you enter this command in interface configuration mode, only duplex mismatches for the specified Ethernet interface are displayed.

If the cdp log mismatch duplex command is disabled in global configuration mode, it cannot be configured per interface using interface configuration mode.

Duplex mismatch can occur only on Ethernet interfaces.

Examples

The following example of the cdp log mismatch duplex command in global configuration mode enables the display of duplex messages from all Ethernet interfaces on the router:

Router(config)# cdp log mismatch duplex 

The following example of the cdp log mismatch duplex command in interface configuration mode enables only the display of duplex messages that may be generated from Ethernet interface 2/1:

Router(config-if)# interface ethernet2/1

Router(config-if)# cdp log mismatch duplex

The following is sample output from the show running-config command. The bold text shows that the cdp log mismatch duplex command is disabled globally.

Router# show running-config

Building configuration...

Current configuration : 1395 bytes
!
version 12.2
!
hostname 7200_C
!
!
interface Ethernet2/1
 no ip address
 duplex half
 no cdp log mismatch duplex
!
!
!
!
!
no cdp log mismatch duplex
cdp timer 5
!
!
!
!
line con 0
line aux 0
line vty 0 4
 password lab

Related Commands

Command
Description

show running-config

Displays the contents of the currently running configuration file.


cdp run

To enable Cisco Discovery Protocol (CDP), use the cdp run command in global configuration mode. To disable CDP, use the no form of this command.

cdp run

no cdp run

Syntax Description

This command has no arguments or keywords.

Defaults

Enabled

Command Modes

Global configuration

Command History

Release
Modification

10.3

This command was introduced.


Usage Guidelines

CDP is enabled by default, which means the Cisco IOS software will receive CDP information. CDP also is enabled on supported interfaces by default. To disable CDP on an interface, use the no cdp enable interface configuration command.


Note Because ODR (on demand routing) uses CDP, the cdp enable, cdp timer, and cdp run commands affect the operation of the router odr global configuration command. For more information on the router odr command, see the Cisco IOS IP Command Reference, Volume 2 of 3: Routing Protocols document.


Examples

In the following example, CDP is disabled globally, then the user attempts to enable CDP on the Ethernet 0 interface:

Router(config)# no cdp run
Router(config)# end
Router# show cdp
% CDP is not enabled
Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.                                                             
Router(config)# int eth0
Router(config-if)# cdp enable
% Cannot enable CDP on this interface, since CDP is not running 
Router(config-if)#

Related Commands

Command
Description

cdp enable

Enables CDP on a supported interface.

cdp timer

Specifies how often the Cisco IOS software sends CDP updates.

router odr

Enables ODR on the hub router.


cdp source-interface

To configure the Cisco Discovery Protocol source interface, use the cdp source-interface command in global configuration mode.

cdp source-interface type number

no cdp source-interface

Syntax Description

type

Type of interface to be configured.

number

Port, connector, or interface card number. These numbers were assigned at the time of installation or when added to a system, and can be displayed with the show interfaces command.


Defaults

No Cisco Discovery Protocol source-interface is specified.

Command Modes

Global configuration

Command History

Release
Modification

12.2(11)T

This command was introduced.


Usage Guidelines

Use of this command ensures that Cisco Discovery Protocol packets use the IP address that has been previously assigned to an interface. Without this command, Cisco Discovery Protocol uses the IP address of the first available interface.

The conditions that an interface should satisfy to be the source interface are as follows:

It should have an IP address.

Its status should be UP.

It should not be an IP unnumbered interface.

When Cisco Discovery Protocol is enabled and the Cisco Discovery Protocol source interface has not been configured, then Cisco Discovery Protocol uses the IP address of the first available interface.

Examples

The following example configures Cisco Discovery Protocol to use the IP address that has been assigned to interface loopback 1.

Router# configure terminal 
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# cdp source-interface loopback 1
Router(config)# exit
Router#

Related Commands

Command
Description

cdp enable

Enables Cisco Discovery Protocol on a supported interface.

cdp run

Reenables Cisco Discovery Protocol on a Cisco device.


cdp timer

To specify how often the Cisco IOS software sends Cisco Discovery Protocol (CDP) updates, use the cdp timer command in global configuration mode. To revert to the default setting, use the no form of this command.

cdp timer seconds

no cdp timer

Syntax Description

seconds

Specifies how often the Cisco IOS software sends CDP updates. The default is 60 seconds.


Defaults

60 seconds

Command Modes

Global configuration

Command History

Release
Modification

10.3

This command was introduced.


Usage Guidelines

The trade-off with sending more frequent CDP updates to provide up-to-date information, is that bandwidth is used more often.


Note The cdp enable, cdp timer, and cdp run commands affect the operation of the IP on demand routing feature (that is, the router odr global configuration command). For more information on the router odr command, see the "On-Demand Routing Commands"  chapter in the Cisco IOS IP Command Reference, Volume 2 of 3: Routing Protocols document.


Examples

In the following example, CDP updates are sent every 80 seconds, less frequently than the default setting of 60 seconds. You might want to make this change if you are concerned about preserving bandwidth.

cdp timer 80

Related Commands

Command
Description

cdp enable

Enables CDP on a supported interface.

cdp holdtime

Specifies the amount of time the receiving device should hold a CDP packet from your router before discarding it.

cdp timer

Specifies how often the Cisco IOS software sends CDP updates.

router odr

Enables ODR on the hub router.

show cdp

Displays global CDP information, including timer and hold-time information.


clear cdp counters

To reset Cisco Discovery Protocol (CDP) traffic counters to zero, use the clear cdp counters command in privileged EXEC mode.

clear cdp counters

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

Release
Modification

10.3

This command was introduced.


Examples

The following example clears the CDP counters. The show cdp traffic output shows that all of the traffic counters have been reset to zero.

Router# clear cdp counters
Router# show cdp traffic

CDP counters:
        Packets output: 0, Input: 0
        Hdr syntax: 0, Chksum error: 0, Encaps failed: 0
        No memory: 0, Invalid packet: 0, Fragmented: 0

Related Commands

Command
Description

clear cdp table

Clears the table that contains CDP information about neighbors.

show cdp traffic

Displays traffic information from the CDP table.


clear cdp table

To clear the table that contains Cisco Discovery Protocol (CDP) information about neighbors, use the clear cdp table command in privileged EXEC mode.

clear cdp table

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

Release
Modification

10.3

This command was introduced.


Examples

The following example clears the CDP table. The output of the show cdp neighbors command shows that all information has been deleted from the table.

Router# clear cdp table 

CDP-AD: Deleted table entry for neon.cisco.com, interface Ethernet0
CDP-AD: Deleted table entry for neon.cisco.com, interface Serial0

Router# show cdp neighbors

Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP
Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID

Related Commands

Command
Description

show cdp neighbors

Displays information about neighbors.


clear cns config stats

To clear the statistics about the CNS configuration agent, use the clear cns config stats command in privileged EXEC mode.

clear cns config stats

Syntax Description

This command has no arguments or keywords.

Defaults

No statistics are cleared.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.3(1)

This command was introduced.


Usage Guidelines

The clear cns config stats command clears all the statistics displayed by the show cns config stats command.

Examples

The following example shows how to clear all of the statistics for the CNS configuration agent:

Router# clear cns config stats

Related Commands

Command
Description

show cns config stats

Displays statistics about the CNS configuration agent.


clear cns counters

To clear all CNS statistics, use the clear cns counters command in privileged EXEC mode.

clear cns counters

Syntax Description

This command has no arguments or keywords.

Defaults

No statistics are cleared.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.3(1)

This command was introduced.


Usage Guidelines

The clear cns counters command clears all the statistics tracked and displayed by CNS agents.

Examples

The following example shows how to clear all of the statistics used by CNS:

Router# clear cns counters

Related Commands

Command
Description

show cns config stats

Displays statistics about the CNS configuration agent.

show cns event stats

Displays statistics about the CNS event agent.

show cns image stats

Displays statistics about the CNS image agent.


clear cns event stats

To clear the statistics about the CNS event agent, use the clear cns event stats command in privileged EXEC mode.

clear cns event stats

Syntax Description

This command has no arguments or keywords.

Defaults

No statistics are cleared.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.3(1)

This command was introduced.


Usage Guidelines

The clear cns event stats command clears all the statistics displayed by the show cns event stats command.

Examples

The following example shows how to clear all of the statistics for the CNS event agent:

Router# clear cns event stats

Related Commands

Command
Description

show cns event stats

Displays statistics about the CNS event agent.


clear cns image connections

To clear the CNS image agent connections statistics, use the clear cns image connections command in privileged EXEC mode.

clear cns image connections

Syntax Description

This command has no arguments or keywords.

Defaults

No statistics are cleared.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.3(1)

This command was introduced.


Usage Guidelines

The clear cns image connections command clears all the statistics displayed by the show cns image connections command.

Examples

The following example shows how to clear all of the connection statistics for the CNS image agent:

Router# clear cns image connections

Related Commands

Command
Description

show cns image connections

Displays connection information for the CNS image agent.


clear cns image status

To clear the CNS image agent status statistics, use the clear cns image status command in privileged EXEC mode.

clear cns image status

Syntax Description

This command has no arguments or keywords.

Defaults

No statistics are cleared.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.3(1)

This command was introduced.


Usage Guidelines

The clear cns image status command clears all the statistics displayed by the show cns image status command.

Examples

The following example shows how to clear all of the status statistics for the CNS image agent:

Router# clear cns image status

Related Commands

Command
Description

show cns image status

Displays status information for the CNS image agent.


clear logging

To clear messages from the logging buffer, use the clear logging command in privileged EXEC mode.

clear logging

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

Release
Modification

11.2

This command was introduced.


Examples

In the following example, the logging buffer is cleared:

Router# clear logging

Clear logging buffer [confirm]
Router#

Related Commands

Command
Description

logging buffered

Logs messages to an internal buffer.

show logging

Displays the state of logging (syslog).


clear logging xml

To clear the contents of the XML system message logging (syslog) buffer, use the clear logging xml command in User EXEC or Priviledged EXEC mode..

clear logging xml

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values.

Command Modes

User EXEC

Privileged EXEC

Command History

Release
Modification

12.2(15)T

This command was introduced.


Usage Guidelines

This command clears the contents of the XML-formatted logging buffer, but does not clear the contents of the standard logging buffer. The system will prompt you to confirm the action before clearing the buffer.

Examples

In the following example, the XML-specific buffer is cleared:

Router# clear logging xml 
Clear XML logging buffer [confirm]?y 

Related Commands

Command
Description

logging buffered xml

Enables system message logging (syslog) to the XML-specific buffer in XML format.

show logging xml

Displays the state of XML-formatted system message logging, followed by the contents of the XML-specific buffer.


clear parser cache

To clear the parse cache entries and hit/miss statistics stored for the Parser Cache feature, use the clear parser cache command in privileged EXEC mode.

clear parser cache

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(5)T

This command was introduced.


Usage Guidelines

The Parser Cache feature optimizes the parsing (translation and execution) of Cisco IOS software configuration command lines by remembering how to parse recently encountered command lines, decreasing the time required to process large configuration files.

The clear parser cache command will free the system memory used by the Parser Cache feature and will erase the hit/miss statistics stored for the output of the show parser statistics EXEC command. This command is only effective when the Parser Cache feature is enabled.

Examples

The following example shows the clearing of the parser cache:

Router# show parser statistics

Last configuration file parsed:Number of Commands:1484, Time:820 ms

Parser cache:enabled, 1460 hits, 26 misses
Router# clear parser cache
Router# show parser statistics
Last configuration file parsed:Number of Commands:1484, Time:820 ms

Parser cache:enabled, 0 hits, 1 misses

Related Commands

Command
Description

parser cache

Enables or disables the Parser Cache feature.

show parser statistics

Displays statistics about the last configuration file parsed and the status of the Parser Cache feature.


clear saa apm cache

To delete files from the SAA Application Performance Monitor (APM) cache, use the clear saa apm cache command in global configuration mode.

clear saa apm cache {local | remote | file filename} [force]

Syntax Description

local

Deletes all local files from the APM cache.

remote

Deletes all remote files from the APM cache.

file filename

Deletes only the specified file from the APM cache.

force

(Optional) Forces the local, remote, or specified file to be deleted. This keyword is required to delete those files tagged as "sticky."


Defaults

No default behavior or values.

Command Modes

Global configuration

Command History

Release
Modification

12.2(2)T

This command was introduced.


Usage Guidelines

This command will not delete files tagged as "sticky" in the APM cache unless the force keyword is used. The sticky bit is set for a file when the file is copied to the router using the saa apm copy command. To check if files have the sticky bit set, use the show saa apm cache command; those files that show a value of 1 in the "SBit" column have the sticky bit enabled, while those with a sticky value of 0 do not have the sticky bit enabled.

Examples

In the following example, all files that are not tagged as "sticky" (as seen in the SBit column of the show saa apm cache output) are deleted from the APM cache:

Router# show saa apm cache 
Cache Size (bytes):100000
Cache used (bytes):2056
   TimeCreated   TimeAccessed   Size Ref Loc Type SBit FileName
09/21 13:31:25 09/21 13:31:48   1170   0   1  SCR    0 user/scripts/ldap-rem.scr
09/21 13:31:20 09/21 13:31:27   1513   0   1  SCR    1 user/scripts/ldap.scr
09/20 14:29:13 09/20 14:29:36    735   0   1  SCR    0 user/scripts/udp-rem.scr

Router# configure terminal 
Router(config)# clear saa apm cache local 
Router(config)# end 
Router# show saa apm cache 
Cache Size (bytes):100000
Cache used (bytes):1513
   TimeCreated   TimeAccessed   Size Ref Loc Type SBit FileName
09/21 13:31:20 09/21 13:31:27   1513   0   1  SCR    1 user/scripts/ldap.scr

Related Commands

Command
Description

show saa apm cache

Displays the amount of memory available in the SAA APM cache and information about the files stored in the cache.


clear tcp

To clear a TCP connection, use the clear tcp command in privileged EXEC mode.

clear tcp {line line-number | local hostname port remote hostname port | tcb address}

Syntax Description

line line-number

Line number of the TCP connection to clear.

local hostname port
remote hostname port

Host name of the local router and port and host name of the remote router and port of the TCP connection to clear.

tcb address

Transmission Control Block (TCB) address of the TCP connection to clear. The TCB address is an internal identifier for the endpoint.


Command Modes

Privileged EXEC

Command History

Release
Modification

11.1

This command was introduced.


Usage Guidelines

The clear tcp command is particularly useful for clearing hung TCP connections.

The clear tcp line line-number command terminates the TCP connection on the specified tty line. Additionally, all TCP sessions initiated from that tty line are terminated.

The clear tcp local hostname port remote hostname port command terminates the specific TCP connection identified by the host name and port pair of the local and remote router.

The clear tcp tcb address command terminates the specific TCP connection identified by the TCB address.

Examples

The following example clears a TCP connection using its tty line number. The show tcp command displays the line number (tty2) that is used in the clear tcp command.

Router# show tcp
    tty2, virtual tty from host router20.cisco.com
    Connection state is ESTAB, I/O status: 1, unread input bytes: 0
    Local host: 171.69.233.7, Local port: 23
    Foreign host: 171.69.61.75, Foreign port: 1058
    Enqueued packets for retransmit: 0, input: 0, saved: 0
    Event Timers (current time is 0x36144):
    Timer          Starts    Wakeups            Next
    Retrans             4          0             0x0
    TimeWait            0          0             0x0
    AckHold             7          4             0x0
       SendWnd             0          0             0x0
    KeepAlive           0          0             0x0
    GiveUp              0          0             0x0
    PmtuAger            0          0             0x0
    iss: 4151109680  snduna: 4151109752  sndnxt: 4151109752     sndwnd:  24576
    irs: 1249472001  rcvnxt: 1249472032  rcvwnd:       4258  delrcvwnd:     30
    SRTT: 710 ms, RTTO: 4442 ms, RTV: 1511 ms, KRTT: 0 ms
    minRTT: 0 ms, maxRTT: 300 ms, ACK hold: 300 ms
Router# clear tcp line 2
    [confirm]
     [OK]

The following example clears a TCP connection by specifying its local router host name and port and its remote router host name and port. The show tcp brief command displays the local (Local Address) and remote (Foreign Address) host names and ports to use in the clear tcp command.

Router# show tcp brief

TCB       Local Address           Foreign Address        (state)
    60A34E9C  router1.cisco.com.23      router20.cisco.1055  ESTAB
Router# clear tcp local router1 23 remote router20 1055
    [confirm]
     [OK]

The following example clears a TCP connection using its TCB address. The show tcp brief command displays the TCB address to use in the clear tcp command.

Router# show tcp brief

    TCB       Local Address           Foreign Address        (state)
    60B75E48  router1.cisco.com.23      router20.cisco.1054  ESTAB
Router# clear tcp tcb 60B75E48
    [confirm]
     [OK]

Related Commands

Command
Description

show tcp

Displays the status of TCP connections.

show tcp brief

Displays a concise description of TCP connection endpoints.


clear xsm

To clear XML Subscription Manager (XSM) client sessions, use the clear xsm command in privileged EXEC mode.

clear xsm [session number]

Syntax Description

session number

(Optional) XSM session ID number of the specific XSM client session you wish to clear.


Defaults

If the optional session number syntax is not used, the clear xsm command clears all XSM client sessions.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(6)E

This command was introduced.

12.2(9)YE

This command was integrated into Cisco IOS Release 12.2(9)YE.

12.2(9)YO1

This command was integrated into Cisco IOS Release 12.2(9)YO1.

12.2(13)T

This command was integrated into Cisco IOS Release 12.2(13)T.


Usage Guidelines

This command disconnects all active client sessions (such as with a VPN Device Manager [VDM]) on the XSM server, unless you state a specific session number. This command allows troubleshooting of the XSM server and its active clients by allowing individual clients to be disconnected. Use the show xsm status command to obtain specific session numbers.

Examples

In the following example, all XSM client sessions are cleared:

Router# clear xsm

In the following example, XSM client session 10 is cleared:

Router# clear xsm session 10 

Related Commands

Command
Description

show xsm status

Displays information and status about clients subscribed to the XSM server.

xsm

Enables XSM client access to the router.


cli

To specify EXEC command line interface (CLI) commands within a Command Scheduler policy list, use the cli command in kron-policy configuration mode. To delete a CLI command from the current policy list, use the no form of this command.

cli command

no cli command

Syntax Description

command

EXEC mode CLI command syntax. Commands must not generate a prompt or allow interruption by any keystroke.


Defaults

No CLI commands are specified.

Command Modes

Kron-policy configuration (config-kron-policy)

Command History

Release
Modification

12.3(1)

This command was introduced.


Usage Guidelines

Use the cli command in conjunction with the kron policy-list command to create a policy list containing EXEC CLI commands to be scheduled to run on the router at a specified time. Use the kron occurrence and policy-list commands to schedule one or more policy lists to run at the same time or interval.

The Command Scheduler process is useful to automate the running of EXEC commands at recurring intervals, and it can be used in remote routers to minimize manual intervention.

Examples

The following example shows how to configure the EXEC command cns image retrieve within the policy list named three-day-list:

Router(config)# kron policy-list three-day-list
Router(config-kron-policy)# cli cns image retrieve server https://10.19.2.3/cns/image/ 
status https://10.19.2.3/cnsstatus/imageinfo/

Related Commands

Command
Description

kron occurrence

Specifies schedule parameters for a Command Scheduler occurrence and enters kron-occurrence configuration mode.

kron policy-list

Specifies a name for a Command Scheduler policy and enters kron-policy configuration mode.

policy-list

Specifies the policy list associated with a Command Scheduler occurrence.


cli (cns)

To specify the command lines of a Cisco Networking Services (CNS) connect template, use the cli command in CNS template connect configuration mode. To disable this configuration, use the no form of this command.

cli config-text

no cli config-text

Syntax Description

config-text

Command line to be included in a CNS connect template.


Defaults

No command lines are specified in the CNS connect template.

Command Modes

CNS template connect configuration

Command History

Release
Modification

12.3(2)XF

This command was introduced.

12.3(8)T

This command was integrated into Cisco IOS Release 12.3(8)T.

12.3(9)

This command was integrated into Cisco IOS Release 12.3(9). The CNS connect variable ${dlci} is not supported in this release.


Usage Guidelines

First use the cns template connect command to enter CNS template connect configuration mode and define the name of the CNS connect template to be configured. Then use the cli command to specify the command lines of the CNS connect template.


Note Effective with Cisco IOS Releases 12.3(8)T and 12.3(9), the config-cli and line-cli commands are replaced by the cli (cns) command.


The command lines specified using the cli command can include CNS connect variables (see Table 12). These variables act as placeholders within the command lines of a CNS connect template. Each variable is defined by an associated discover command. Before a CNS connect template that contains these variables is applied to a router's configuration, the variables are replaced by the values defined by their associated discover command. For example, if the discover interface serial command was configured, and you were able to connect to the CNS configuration engine using Serial0/0, then the cli ip route 0.0.0.0 0.0.0.0 ${interface} command would generate the cli ip route 0.0.0.0 0.0.0.0 serial0/0 command.


Note When creating a CNS connect template, you must enter the exit command to complete the configuration of the template and exit from CNS template connect configuration mode. This requirement was implemented to prevent accidentally entering a command without the cli command.


Table 12 Summary of the CNS Connect Variables

Variable
Description

${line}

The line type defined by the associated discover line line-type command.

${controller}

The controller type defined by the associated discover controller controller-type command.

${interface}

The interface type defined by the associated discover interface command.

${dlci}

The active DLCI defined by the associated discover dlci command.

${next-hop}

The next hop interface. This variable is identical to the ${interface} variable unless the discover dlci command has been configured. In this case, the ${next-hop} variable is identical to the ${interface}.{subinterface} variable, where the {subinterface} variable is specified by the discover dlci command.

The ${next-hop} variable should only be used in the CNS connect templates after the last discover command has been entered.

A typical use of this variable is to allow the default IP route to be configured to send traffic towards the CNS configuration engine. Note that the CNS configuration engine may not be on the same LAN as the router. Therefore, configuring a route to the CNS configuration engine may require deployment-specific knowledge. Common practice is to define a default route to the interface using the ip route command (for example, cli ip route 0.0.0.0 0.0.0.0 ${next-hop}).

$$

A literal substitution of the $ symbol.



Note Effective with Cisco IOS Releases 12.3(8)T and 12.3(9), the & variable is replaced by the ${interface} variable.


Examples

The following example shows how to configure a CNS connect template named template1:

Router (config)# cns template connect template-1
Router (config-templ-conn)# cli command-1
Router (config-templ-conn)# cli command-2
Router (config-templ-conn)# cli no command-3
Router (config-templ-conn)# exit
Router (config)#

When the template1 template is applied, the following commands are sent to the router's parser:

command-1
command-2
no command-3

When the template1 template is removed from the router's configuration after an unsuccessful ping attempt to the CNS configuration engine, the following commands are sent to the router's parser:

no command-1
no command-2
command-3

Related Commands

Command
Description

cns connect

Enters CNS connect configuration mode and defines the parameters of a CNS connect profile for connecting to the CNS configuration engine.

cns template connect

Enters CNS template connect configuration mode and defines the name of a CNS connect template.

discover (cns)

Defines the interface parameters within a CNS connect profile for connecting to the CNS configuration engine.

template (cns)

Specifies a list of CNS connect templates within a CNS connect profile to be applied to a router's configuration.


clock calendar-valid

To configure a system as an authoritative time source for a network based on its hardware clock (calendar), use the clock calendar-valid command in global configuration mode. To specify that the hardware clock is not an authoritative time source, use the no form of this command.

clock calendar-valid

no clock calendar-valid

Syntax Description

This command has no arguments or keywords.

Defaults

The router is not configured as a time source.

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

Some platforms have a hardware clock that is separate from the software clock. The hardware clock runs continuously, even if the router is powered off or rebooted. If no outside time source is available on your network, use this command to make the hardware clock an authoritative time source.

Because the hardware clock is not as accurate as other time sources, you should configure this command only when a more accurate time source (such as NTP) is not available.

Examples

The following example configures a router as the time source for a network based on its hardware clock:

Router(config)# clock calendar-valid

Related Commands

Command
Description

ntp master

Configures the Cisco IOS software as an NTP master clock to which peers synchronize themselves when an external NTP source is not available.

vines time use-system

Sets VINES network time based on the system time.


clock read-calendar

To manually read the hardware clock (calendar) settings into the software clock, use the clock read-calendar command in EXEC mode.

clock read-calendar

Syntax Description

This command has no arguments or keywords.

Command Modes

EXEC

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

Some platforms have a hardware clock that is separate from the software clock. The hardware clock runs continuously, even if the router is powered off or rebooted. When the router is rebooted, the hardware clock is automatically read into the software clock. However, you may use this command to manually read the hardware clock setting into the software clock. This command is useful if the calendar set command has been used to change the setting of the hardware clock.

Examples

The following example configures the software clock to set its date and time by the hardware clock setting:

Router> clock read-calendar

Related Commands

Command
Description

calendar set

Sets the hardware clock.

clock set

Manually sets the software clock.

clock update-calendar

Performs a one-time update of the hardware clock from the software clock.

ntp update-calendar

Periodically updates the hardware clock from the software clock.


clock set

To manually set the system software clock, use one of the following formats of the clock set command in privileged EXEC mode.

clock set hh:mm:ss day month year

clock set hh:mm:ss month day year

Syntax Description

hh:mm:ss

Current time in hours (24-hour format), minutes, and seconds.

day

Current day (by date) in the month.

month

Current month (by name).

year

Current year (no abbreviation).


Command Modes

Privileged EXEC mode

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

Generally, if the system is synchronized by a valid outside timing mechanism, such as a Network Time Protocol (NTP) or VINES clock source, or if you have a router with hardware clock, you need not set the software clock. Use this command if no other time sources are available. The time specified in this command is assumed to be in the timezone specified by the configuration of the clock timezone command.

Examples

The following example manually sets the software clock to 7:29 p.m. on May 13, 2003:

Router# clock set 19:29:00 13 May 2003 

Related Commands

Command
Description

calendar set

Sets the hardware clock.

clock read-calendar

Performs a one-time update of the software clock from the hardware clock (calendar).

clock summer-time

Configures the system to automatically switch to summer time (daylight saving time).

clock timezone

Sets the time zone for display purposes.


clock summer-time

To configure the system to automatically switch to summer time (daylight saving time), use one of the formats of the clock summer-time command in global configuration mode. To configure the Cisco IOS software not to automatically switch to summer time, use the no form of this command.

clock summer-time zone recurring [week day month hh:mm week day month hh:mm [offset]]

clock summer-time zone date date month year hh:mm date month year hh:mm [offset]

clock summer-time zone date month date year hh:mm month date year hh:mm [offset]

no clock summer-time

Syntax Description

zone

Name of the time zone (for example, "PDT" for Pacific Daylight Time) to be displayed when summer time is in effect. The length of the zone argument is limited to 7 characters.

recurring

Indicates that summer time should start and end on the corresponding specified days every year.

date

Indicates that summer time should start on the first specific date listed in the command and end on the second specific date in the command.

week

(Optional) Week of the month (1 to 5 or last).

day

(Optional) Day of the week (Sunday, Monday, and so on).

date

Date of the month (1 to 31).

month

(Optional) Month (January, February, and so on).

year

Year (1993 to 2035).

hh:mm

(Optional) Time (military format) in hours and minutes.

offset

(Optional) Number of minutes to add during summer time (default is 60).


Defaults

Summer time is disabled. If the clock summer-time zone recurring command is specified without parameters, the summer time rules default to United States rules. Default of the offset argument is 60.

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

Use this command if you want to automatically switch to summer time (for display purposes only). Use the recurring form of the command if the local summer time rules are of this form. Use the date keyword to specify a start and end date for summer time if you cannot use the recurring keyword.

In both the date and recurring forms of the command, the first part of the command specifies when summer time begins, and the second part specifies when it ends. All times are relative to the local time zone. The start time is relative to standard time. The end time is relative to summer time. If the starting month is chronologically after the ending month, the system assumes that you are in the southern hemisphere.

Examples

The following example specifies that summer time starts on the first Sunday in April at 2 a.m. and ends on the last Sunday in October at 2 a.m.:

Router(config)# clock summer-time PDT recurring 1 Sunday April 2:00 last Sunday October 
2:00

If you live in a place where summer time does not follow the pattern in the first example, you can specify the exact date and times. In the following example, daylight saving time (summer time) is configured to start on October 12, 1997 at 2 a.m., and end on April 26, 1998 at 2 a.m.:

Router(config)# clock summer-time date 12 October 1997 2:00 26 April 1998 2:00

Related Commands

Command
Description

calendar set

Sets the hardware clock.

clock timezone

Sets the time zone for display purposes.


clock timezone

To set the time zone for display purposes, use the clock timezone command in global configuration mode. To set the time to Coordinated Universal Time (UTC), use the no form of this command.

clock timezone zone hours-offset [minutes-offset]

no clock timezone

Syntax Description

zone

Name of the time zone to be displayed when standard time is in effect. The length of the zone argument is limited to 7 characters.

hours-offset

Hours difference from UTC.

minutes-offset

(Optional) Minutes difference from UTC.


Defaults

UTC

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

The system internally keeps time in UTC, so this command is used only for display purposes and when the time is manually set.

Table 13 lists common time zone acronyms used for the zone argument.

Table 13 Common Time Zone Acronyms 

Acronym
Time Zone Name and UTC Offset
Europe
 

GMT

Greenwich Mean Time, as UTC

BST

British Summer Time, as UTC + 1 hour

IST

Irish Summer Time, as UTC + 1 hour

WET

Western Europe Time, as UTC

WEST

Western Europe Summer Time, as UTC + 1 hour

CET

Central Europe Time, as UTC + 1

CEST

Central Europe Summer Time, as UTC + 2

EET

Eastern Europe Time, as UTC + 2

EEST

Eastern Europe Summer Time, as UTC + 3

MSK

Moscow Time, as UTC + 3

MSD

Moscow Summer Time, as UTC + 4

United States and Canada
 

AST

Atlantic Standard Time, as UTC -4 hours

ADT

Atlantic Daylight Time, as UTC -3 hours

ET

Eastern Time, either as EST or EDT, depending on place and time of year

EST

Eastern Standard Time, as UTC -5 hours

EDT

Eastern Daylight Saving Time, as UTC -4 hours

CT

Central Time, either as CST or CDT, depending on place and time of year

CST

Central Standard Time, as UTC -6 hours

CDT

Central Daylight Saving Time, as UTC -5 hours

MT

Mountain Time, either as MST or MDT, depending on place and time of year

MST

Mountain Standard Time, as UTC -7 hours

MDT

Mountain Daylight Saving Time, as UTC -6 hours

PT

Pacific Time, either as PST or PDT, depending on place and time of year

PST

Pacific Standard Time, as UTC -8 hours

PDT

Pacific Daylight Saving Time, as UTC -7 hours

AKST

Alaska Standard Time, as UTC -9 hours

AKDT

Alaska Standard Daylight Saving Time, as UTC
-8 hours

HST

Hawaiian Standard Time, as UTC -10 hours

Australia
 

WST

Western Standard Time, as UTC + 8 hours

CST

Central Standard Time, as UTC + 9.5 hours

EST

Eastern Standard/Summer Time, as UTC + 10 hours (+11 hours during summer time)


Table 14lists an alternative method for referring to time zones, in which single letters are used to refer to the time zone difference from UTC. Using this method, the letter Z is used to indicate the zero meridian, equivalent to UTC, and the letter J (Juliet) is used to refer to the local time zone. Using this method, the International Date Line is between time zones M and Y.

Table 14 Single-Letter Time Zone Designators 

Letter Designator
Word Designator
Difference from UTC

Y

Yankee

UTC -12 hours

X

Xray

UTC -11 hours

W

Whiskey

UTC -10 hours

V

Victor

UTC -9 hours

U

Uniform

UTC -8 hours

T

Tango

UTC -7 hours

S

Sierra

UTC -6 hours

R

Romeo

UTC -5 hours

Q

Quebec

UTC -4 hours

P

Papa

UTC -3 hours

O

Oscar

UTC -2 hours

N

November

UTC -1 hour

Z

Zulu

Same as UTC

A

Alpha

UTC +1 hour

B

Bravo

UTC +2 hours

C

Charlie

UTC +3 hours

D

Delta

UTC +4 hours

E

Echo

UTC +5 hours

F

Foxtrot

UTC +6 hours

G

Golf

UTC +7 hours

H

Hotel

UTC +8 hours

I

India

UTC +9 hours

K

Kilo

UTC +10 hours

L

Lima

UTC +11 hours

M

Mike

UTC +12 hours


The following example sets the time zone to Pacific Standard Time (PST), which is 8 hours behind UTC:

Router(config)# clock timezone PST -8

The following example sets the time zone to Atlantic Time (AT) for Newfoundland, Canada, which is 3.5 hours behind UTC:

Router(config)# clock timezone AT -3 30

Related Commands

Command
Description

calendar set

Sets the hardware clock.

clock set

Manually set the software clock.

clock summer-time

Configures the system to automatically switch to summer time (daylight saving time).

show clock

Displays the software clock.