Table Of Contents
distributions-of-statistics-kept
show rtr collection-statistics
show rtr distribution-statistics
snmp-server trap-authentication
statistics-distribution-interval
System Management Commands
This chapter describes the commands used to manage the system and its performance on the network. In general, system or network management falls into the following categories. The commands that perform the tasks in these management categories are described in this chapter unless specified otherwise.
•
Configuration Management
The configuration of network routers determines how the network operates. To manage router configurations, you need to list and compare configuration files on running routers, store configuration files on network servers for shared access, and perform software installations and upgrades. (Configuration management commands required to perform these tasks are described in the "System and Configuration File Load Commands" chapter in the Configuration Fundamentals Command Reference.)
Other configuration management tasks include naming the router, setting time services, configuring for synchronous logging of unsolicited messages and debug output, configuring a router for weighted fair queueing, and configuring SNMP support. Configuration management commands required to perform these tasks are described in this chapter.
•
To manage network faults, you need to discover, isolate, and fix the problems. You can discover problems with the system's monitoring commands, isolate problems with the system's test commands, and resolve problems with other commands, including debug.
This chapter describes general fault management commands. For detailed troubleshooting procedures and a variety of scenarios, see the Troubleshooting Internetworking Systems publication. For complete details on all debug commands, see the Debug Command Reference.
•
To manage system performance, you need to monitor and determine response time, error rates, and availability. Once these factors are determined, you can perform load-balancing and modify system parameters to enhance performance. For example, priority queuing allows you to prioritize traffic order. You can configure fast and autonomous switching to improve network throughput, as described in the "Configuring Interfaces" chapter of the Configuration Fundamentals Configuration Guide.
See the Internetwork Design Guide for additional information.
For system management configuration tasks and examples, refer to the chapter entitled "Managing the System" in the Configuration Fundamentals Configuration Guide.
access-enable
To enable the router to create a temporary access list entry in a dynamic access list, use the access-enable EXEC command.
access-enable [host] [timeout minutes]
Syntax Description
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
This command enables the lock-and-key access feature.
You should always define either an idle timeout (with the timeout keyword in this command) or an absolute timeout (with the timeout keyword in the access-list command). Otherwise, the temporary access list entry will remain, even after the user has terminated his session.
Example
The following example causes the software to create a temporary access list entry and tells the software to enable access only for the host from which the Telnet session originated. If the access list entry is not accessed within 2 minutes, it is deleted.
autocommand access-enable host timeout 2Related Commands
A dagger (†) indicates that the command is documented outside this chapter.
access-list (extended) †
autocommand †access-template
To manually place a temporary access list entry on a router to which you are connected, use the access-template EXEC command.
access-template [access-list-number] [dynamic-name] [source] [destination] [timeout minutes]
Syntax Description
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
This command provides a way to enable the lock-and-key access feature.
You should always define either an idle timeout (with the timeout keyword in this command) or an absolute timeout (with the timeout keyword in the access-list command). Otherwise, the dynamic access list will remain, even after the user has terminated the session.
Example
In the following example, the software enables IP access on incoming packets in which the source address is 172.30.1.129 and the destination address is 172.16.52.12. All other source and destination pairs are discarded.
access-template 101 payroll host 172.30.1.129 host 172.16.52.12 timeout 2Related Commands
A dagger (†) indicates that the command is documented outside this chapter.
access-list (extended) †
autocommand †
clear access-template †alias
To create a command alias, use the alias global configuration command. Use the no form of this command to delete all aliases in a command mode or to delete a specific alias, and to revert to the original command syntax.
alias mode alias-name alias-command-line
no alias mode [alias-name]Syntax Description
mode
Command mode of the original and alias commands. See for a list of options for this argument.
alias-name
Command alias.
alias-command-line
Original command syntax.
Defaults
Default aliases are in EXEC mode as follows:
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
You can use simple words or abbreviations as aliases. The aliases in the Default section are predefined. They can be turned off using the no alias command.
shows the acceptable options for the mode argument in the alias global configuration command.
See the summary of command modes in the "User Interface" chapter in the Configuration Fundamentals Configuration Guide for more information about command modes.
When you use online help, command aliases are indicated by an asterisk (*), as follows:
Router#lo?*lo=logout lock login logoutWhen you use online help, aliases that contain spaces (for example, telnet device.cisco.com 25) are displayed as follows:
Router# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)# alias exec device-mail telnet device.cisco.com 25Router(config)# endRouter# device-mail?*device-mail="telnet device.cisco.com 25"When you use online help, the alias is expanded and replaced with the original command, as shown in the following example with the td alias:
Router(config)# alias exec td trace deviceRouter(config)# ^ZRouter# t?*td="trace device" telnet terminal test tn3270traceTo 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# t?telnet terminal test tn3270 traceAs 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 telet device. The /debug and /line switches can be added to telnet device to modify the command:
Router(config)# alias exec td telnet deviceRouter(config)# ^ZRouter# td ?/debug Enable telnet debugging mode/line Enable telnet line mode...whois Whois port<cr>Router# telnet deviceYou must enter the complete syntax for the alias command. Partial syntax for aliases are not accepted. In the following example, the parser does not recognize the command t as indicating the alias td.
bones# t% Ambiguous command: "t"Example
In the following example, the alias fixmyrt is created for the ip route198.92.116.16.
alias exec fixmyrt clear ip route 198.92.116.16Related Command
buckets-of-history-kept
To set the number of history buckets that are kept during the response time reporter probe's lifetime, use the buckets-of-history-kept response time reporter configuration command. Use the no form of this command to return to the default value.
buckets-of-history-kept size
no buckets-of-history-keptSyntax Description
size
Number of history buckets kept during the response time reporter probe's lifetime. The default is 50 buckets.
Default
50 buckets
Command Mode
Response time reporter configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
A response time reporter probe can collect history and capture statistics. 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 response time reporter configuration command to collect history. You can optionally adjust the buckets-of-history-kept, filter-for-history, and sample-of-history-kept response time reporter configuration commands.
When the number of buckets reaches the size specified, no further history for this life is stored.
Note
If history is collected, each bucket contains one or more history entries from the probe. When the probe type is pathEcho, an entry is created for each hop along the path that the probe takes to reach its destination. The type of entry stored in the history table is controlled by the filter-for-history response time reporter 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 response time reporter configuration commands.
Each time the probe starts a response time reporter operation, a new bucket is created until the number of history buckets matches the specified size or the probe's lifetime expires. History buckets do not wrap. The probe's lifetime is defined by the rtr schedule global configuration command. The probe starts a response time reporter operation based on the seconds specified by the frequency response time reporter configuration command.
Example
In the following example, probe 1 is configured to keep 25 history buckets during the probe's lifetime:
rtr 1type echo protocol ipIcmpEcho 172.16.161.21buckets-of-history-kept 25lives-of-history-kept 1Related Commands
filter-for-history
lives-of-history-kept
rtr
rtr schedule
samples-of-history-keptbuffers
Use the buffers global configuration command to make adjustments to initial buffer pool settings and to the limits at which temporary buffers are created and destroyed. Use the no form of this command to return the buffers to their default size.
buffers {small | middle | big | verybig | large | huge | type number} {permanent | max-free
| min-free | initial} number
no buffers {small | middle | big | verybig | large | huge | type number} {permanent | max-free
| min-free | initial} numberSyntax Description
Default
The default number of buffers in a pool is determined by the hardware configuration and can be displayed with the EXEC show buffers command.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Normally you need not adjust these parameters; do so only after consulting with technical support personnel. Improper settings can adversely impact system performance.
You cannot configure FDDI buffers.
Examples of Public Buffer Pool Tuning
In the following example, the system will try to keep at least 50 small buffers free:
buffers small min-free 50In the following example, the permanent buffer pool allocation for big buffers is increased to 200:
buffers big permanent 200Example 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.
In the following example, the permanent Ethernet 0 interface buffer pool on a Cisco 4000 is increased to 96 because the Ethernet 0 buffer pool is depleted:
buffers ethernet 0 permanent 96Related Commands
buffers huge size
Use the buffers huge size global configuration command to dynamically resize all huge buffers to the value you specify. Use the no form of this command to restore the default buffer values.
buffers huge size number
no buffers huge size numberSyntax Description
Default
18024 bytes
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Use only after consulting with technical support personnel. The buffer size cannot be lowered below the default.
Example
In the following example, the system will resize huge buffers to 20000 bytes:
buffers huge size 20000Related Commands
calendar set
To set the system calendar for a Cisco 7000 series, Cisco 7200 series, or Cisco 4500 series, use the calendar set EXEC command.
calendar set hh:mm:ss day month year
calendar set hh:mm:ss month day yearSyntax Description
hh:mm:ss
Current time in hours (military format), minutes, and seconds.
day
Current day (by date) in the month.
month
Current month (by name).
year
Current year (no abbreviation).
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
After you set the Cisco 7000, Cisco 7200, or Cisco 4500 calendar, the system clock will be automatically set when the system is restarted or when the clock read-calendar EXEC command is issued. The calendar maintains its accuracy, even after a power failure or system reboot has occurred. The time specified in this command is relative to the configured time zone.
Example
In the following example, the system calendar is manually set to 1:32 p.m. on July 23, 1993:
calendar set 13:32:00 23 July 1993Related Commands
clock read-calendar
clock set
clock summer-time
clock timezone
clock update-calendarcdp enable
To enable Cisco Discovery Protocol (CDP) on an interface, use the cdp enable interface configuration command. Use the no form of this command to disable CDP on an interface.
cdp enable
no cdp enableSyntax Description
This command has no arguments or keywords.
Default
Enabled at the global level and on all supported interfaces.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
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
Example
In the following example, CDP is enabled on Ethernet interface 0:
interface ethernet 0cdp enableRelated Command
cdp holdtime
To specify the amount of time the receiving device should hold a CDP packet from your router before discarding it, use the cdp holdtime global configuration command. Use the no form of this command to revert to the default setting.
cdp holdtime seconds
no cdp holdtimeSyntax Description
Default
180 seconds
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
CDP packets are sent with time-to-live, or hold time, that is nonzero after an interface is enabled and a hold time of 0 immediately before an interface is idled down.
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.
Example
In the following example, the CDP packets being sent from your router should be held by the receiving device for 60 seconds before being discarded. You might want to set the hold time lower than the default setting of 180 seconds if information about your router changes often and you want the receiving devices to purge this information more quickly.
cdp holdtime 60Related Commands
cdp run
To enable CDP, use the cdp run global configuration command. Use the no form of this command to disable CDP.
cdp run
no cdp runSyntax Description
This command has no arguments or keywords.
Default
Enabled
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
CDP is enabled on your router 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
Example
In the following example, CDP is disabled:
no cdp runRelated Command
cdp timer
To specify how often the Cisco IOS software sends CDP updates, use the cdp timer global configuration command. Use the no form of this command to revert to the default setting.
cdp timer seconds
no cdp timerSyntax Description
Default
60 seconds
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
The trade-off with sending more frequent transmissions is providing up-to-date information versus using bandwidth more often.
Note
Example
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 80Related Commands
clear cdp counters
To reset CDP traffic counters to zero (0), use the clear cdp counters privileged EXEC command.
clear cdp counters
Syntax Description
This command has no arguments or keywords.
Command Mode
Privileged EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
Example
In the following example, the CDP counters have been cleared. The show cdp traffic output shows that all of the traffic counters have been reset to zero (0).
Router# clear cdp countersRouter# show cdp trafficCDP counters:Packets output: 0, Input: 0Hdr syntax: 0, Chksum error: 0, Encaps failed: 0No memory: 0, Invalid packet: 0, Fragmented: 0Related Commands
clear cdp table
show cdp trafficclear cdp table
To clear the table that contains CDP information about neighbors, use the clear cdp table privileged EXEC command.
clear cdp table
Syntax Description
This command has no arguments or keywords.
Command Mode
Privileged EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
Example
In the following example, the CDP table is cleared. The output of the show cdp neighbors command shows that all information has been deleted from the table.
Router# clear cdp tableCDP-AD: Deleted table entry for neon.cisco.com, interface Ethernet0CDP-AD: Deleted table entry for neon.cisco.com, interface Serial0Router# show cdp neighborsCapability Codes: R - Router, T - Trans Bridge, B - Source Route BridgeS - Switch, H - Host, I - IGMPDevice ID Local Intrfce Holdtme Capability Platform Port IDRelated Commands
clear cdp counters
show cdp neighborsclear logging
To clear messages from the logging buffer, use the clear logging privileged EXEC command.
clear logging
Syntax Description
This command has no arguments or keywords.
Command Mode
Privileged EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Example
In the following example, the logging buffer is cleared.
Router# clear loggingClear logging buffer [confirm]Router#Related Commands
clock calendar-valid
To configure the Cisco 7000 series or the Cisco 4500 as a time source for a network based on its calendar, use the clock calendar-valid global configuration command. Use the no form of this command to set the Cisco IOS software so that the calendar is not an authoritative time source.
clock calendar-valid
no clock calendar-validSyntax Description
This command has no arguments or keywords.
Default
Neither the Cisco 7000 nor the Cisco 4500 are not configured as a time source.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Use this command if no outside time source is available.
Example
In the following example, the Cisco 7000 is configured as the time source for a network based on its calendar:
clock calendar-validRelated Commands
A dagger (†) indicates that the command is documented outside this chapter.
ntp master
vines time use-system †clock read-calendar
To manually read the calendar into either the Cisco 7000 series, Cisco 7200 series, or Cisco 4500 series clock, use the clock read-calendar EXEC command.
clock read-calendar
Syntax Description
This command has no arguments or keywords.
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
When either the Cisco 7000 series, Cisco 7200 series, or Cisco 4500 series calendar is rebooted, the calendar is automatically read into the system clock. However, you may use this command to manually read the calendar setting into the system clock. This command is useful if the calendar set command has been used to change the setting of the calendar.
Example
In the following example, the system clock is configured to set its date and time by the calendar setting:
clock read-calendarRelated Commands
calendar set
clock set
clock update-calendar
ntp update-calendarclock set
To manually set the system clock, use the clock set EXEC command.
clock set hh:mm:ss day month year
clock set hh:mm:ss month day yearSyntax Description
hh:mm:ss
Current time in hours (military format), minutes, and seconds.
day
Current day (by date) in the month.
month
Current month (by name).
year
Current year (no abbreviation).
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Generally, if the system is synchronized by a valid outside timing mechanism, such as an NTP or VINES clock source, or if you have a Cisco 7000 or Cisco 7200 with calendar capability, you do not need to set the system clock. Use this command if no other time sources are available. The time specified in this command is relative to the configured time zone.
Example
In the following example, the system clock is manually set to 1:32 p.m. on July 23, 1993:
clock set 13:32:00 23 July 1993Related Commands
calendar set
clock read-calendar
clock summer-time
clock timezoneclock summer-time
To configure the system to automatically switch to summer time (daylight savings time), use one of the formats of the clock summer-time configuration command. Use the no form of this command to configure the Cisco IOS software not to automatically switch to summer time.
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-timeSyntax Description
Default
Summer time is disabled. If clock summer-time zone recurring is specified without parameters, the summer time rules default to United States rules. Default of offset is 60.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
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 form to specify a start and end date for summer time if you cannot use the first form.
In both 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 after the ending month, the system assumes that you are in the Southern Hemisphere.
Examples
In the following example, summer time starts on the first Sunday in April at 02:00 and ends on the last Sunday in October at 02:00:
clock summer-time PDT recurring 1 Sunday April 2:00 last Sunday October 2:00If you live in a place where summer time does not follow the pattern in the first example, you could set it to start on October 12, 1993 at 02:00, and end on April 28, 1994 at 02:00, with the following example:
clock summer-time date 12 October 1993 2:00 28 April 1994 2:00Related Commands
clock timezone
To set the time zone for display purposes, use the clock timezone global configuration command. To set the time to Coordinated Universal Time (UTC), use the no form of this command.
clock timezone zone hours [minutes]
no clock timezoneSyntax Description
zone
Name of the time zone to be displayed when standard time is in effect.
hours
Hours offset from UTC.
minutes
(Optional) Minutes offset from UTC.
Default
UTC
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The system internally keeps time in UTC, so this command is used only for display purposes and when the time is manually set.
Example
In the following example, the timezone is set to Pacific Standard Time and is offset 8 hours behind UTC:
clock timezone PST -8Related Commands
calendar set
clock set
clock summer-time
show clockclock update-calendar
To set the Cisco 7000, Cisco 7200, or Cisco 4500 calendar from the system clock, use the clock update-calendar EXEC command.
clock update-calendar
Syntax Description
This command has no arguments or keywords.
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
If the system clock and calendar are not synchronized, and the system clock is more accurate, use this command to update the Cisco 7000 series, Cisco 7200 series, or Cisco 4500 series calendar to the correct date and time.
Example
In the following example, the current time is copied from the system clock to the Cisco 7000 calendar:
clock update-calendarRelated Commands
clock read-calendar
ntp update-calendarcustom-queue-list
To assign a custom queue list to an interface, use the custom-queue-list interface configuration command. To remove a specific list or all list assignments, use the no form of the command.
custom-queue-list list
no custom-queue-list [list]Syntax Description
Default
No custom queue list is assigned.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Note
Only one queue list can be assigned per interface. Use this command in place of the priority-list command (not in addition to it). Custom queuing allows a fairness not provided with priority queuing. With custom queuing, you can control the interfaces' available bandwidth when it is unable to accommodate the aggregate traffic enqueued. Associated with each output queue is a configurable byte count, which specifies how many bytes of data should be delivered from the current queue by the system before the system moves on to the next queue. When a particular queue is being processed, packets are sent until the number of bytes sent exceeds the queue byte count or until the queue is empty.
Use the show queuing custom and show interface commands to display the current status of the custom output queues.
Example
In the following example, custom queue list number 3 is assigned to serial interface 0:
interface serial 0custom-queue-list 3Related Commands
queue-list default
queue-list interface
queue-list protocol
queue-list queue byte-count
queue-list queue limitdistributions-of-statistics-kept
To set the number of statistic distributions kept per hop during the response time reporter probe's lifetime, use the distributions-of-statistics-kept response time reporter configuration command. Use the no form of this command to return to the default value.
distributions-of-statistics-kept size
no distributions-of-statistics-keptSyntax Description
Default
1 distribution
Command Mode
Response time reporter configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
In most situations, you do not need to change the statistic distribution size for the response time reporter. Only change the size when distributions are needed (for example, when performing statistical modeling of your network).
Note
When the number of distributions reaches the size specified, no further distribution information is stored.
Example
In the following example, the distribution is set to 5 and the distribution interval is set to 10 ms. This means that the first distribution will contain statistics from 0 to 9 ms, the second distribution will contain statistics from 10 to 19 ms, the third distribution will contain statistics from 20 to 29 ms, the fourth distribution will contain statistics from 30 to 39 ms, and the fifth distribution will contain statistics from 40 ms to infinity.
rtr 1type echo protocol ipIcmpEcho 172.16.161.21distribution-of-statistics-kept 5statistics-distribution-interval 10Related Commands
hops-of-statistics-kept
hours-of-statistics-kept
paths-of-statistics-kept
rtr
statistics-distribution-intervaldownward-compatible-config
To generate a configuration that is compatible with an earlier Cisco IOS Release, use the downward-compatible-config global configuration command. To remove this feature, use the no form of this command.
downward-compatible-config version
no downward-compatible-configSyntax Description
Default
Disabled
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
In Cisco IOS Release 10.3, IP access lists changed format. Use this command to regenerate a configuration in a format prior to Release 10.3 if you are going to downgrade from a Release 10.3 or later to an earlier release. The earliest release this command accepts is 10.2.
When this command is configured, the router attempts to generate a configuration that is compatible with the specified version. Currently, this command affects only IP access lists.
Under some circumstances, the software might not be able to generate a fully backward-compatible configuration. In such a case, the software issues a warning message.
Example
In the following example, the router attempts to generate a configuration file compatible with Cisco IOS Release 10.2:
downward-compatible-config 10.2Related Commands
A dagger (†) indicates that the command is documented outside this chapter.
access-list (extended) †
access-list (standard) †exception core-file
To specify the name of the core dump file, use the exception core-file global configuration command. To return to the default core filename, use the no form of this command.
exception core-file name
no exception core-fileSyntax Description
Default
The core file is named hostname-core, where hostname is the name of the router.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
CautionUse the exception commands only under the direction of a technical support representative. Creating a core dump while the router is functioning in a network can disrupt network operation. The resulting binary file, which is very large, must be transferred to a TFTP, FTP, or rcp server and subsequently interpreted by technical personnel who have access to source code and detailed memory maps.
If you use TFTP to dump the core file to a server, the router will only dump the first 16 MB of the core file. If the router's memory is larger than 16 MB, the whole core file will not be copied to the server. Therefore, use rcp or FTP to dump the core file.
Example
The following example configures a router to use FTP to dump a core file named dumpfile to the FTP server at 172.17.92.2 when it crashes:
ip ftp username redip ftp password blueexception protocol ftpexception dump 172.17.92.2exception core-file dumpfileRelated Commands
exception dump
exception memory
exception protocol
ip ftp password
ip ftp usernameexception dump
To configure the router to dump a core file to a particular server when the router crashes, use the exception dump global configuration command. To disable core dumps, use the no form of this command.
exception dump ip-address
no exception dumpSyntax Description
Default
Disabled
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
CautionUse the exception commands only under the direction of a technical support representative. Creating a core dump while the router is functioning in a network can disrupt network operation. The resulting binary file, which is very large, must be transferred to a TFTP, FTP, or rcp server and subsequently interpreted by technical personnel who have access to source code and detailed memory maps.
If you use TFTP to dump the core file to a server, the router will only dump the first 16 MB of the core file. If the router's memory is larger than 16 MB, the whole core file will not be copied to the server. Therefore, use rcp or FTP to dump the core file.
The core dump is written to a file named hostname-core on your server, where hostname is the name of the router. You can change the name of the core file by configuring the exception core-file command.
This procedure can fail for certain types of system crashes. However, if successful, the core dump file will be the size of the memory available on the processor (for example, 16 MB for a CSC/4).
Example
The following example configures a router to use FTP to dump a core file to the FTP server at 172.17.92.2 when it crashes:
ip ftp username redip ftp password blueexception protocol ftpexception dump 172.17.92.2Related Commands
exception core-file
exception memory
exception protocol
ip ftp password
ip ftp username
ip rcmd remote-usernameexception memory
To cause the router to create a core dump and reboot when certain memory size parameters are violated, use the exception memory global configuration command. To disable the rebooting and core dump, use the no form of this command.
exception memory {fragment size | minimum size}
no exception memory {fragment | minimum}Syntax Description
fragment size
The minimum contiguous block of memory in the free pool, in bytes.
minimum size
The minimum size of the free memory pool, in bytes.
Default
Disabled
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
CautionUse the exception commands only under the direction of a technical support representative. Creating a core dump while the router is functioning in a network can disrupt network operation. The resulting binary file, which is very large, must be transferred to a TFTP, FTP, or rcp server and subsequently interpreted by technical personnel who have access to source code and detailed memory maps.
This command is useful to troubleshoot memory leaks.
The size is checked every 60 seconds. If you enter a size that is greater than the free memory, a core dump and router reload is generated after 60 seconds.
The exception dump command must be configured in order to generate a core file. If the exception dump command is not configured, the router reloads without generating a core dump.
Example
The following example configures the router to monitor the free memory. If the amount of free memory falls below 250,000 bytes,the router will dump the core file and reload.
exception dump 131.108.92.2exception core-file memory.overrunexception memory minimum 250000Related Commands
exception core-file
exception dump
exception protocol
ip ftp password
ip ftp usernameexception protocol
To configure the protocol used for core dumps, use the exception protocol global configuration command. To configure the router to use the default protocol, use the no form of this command.
exception protocol {ftp | rcp | tftp}
no exception protocolSyntax Description
ftp
Use FTP for core dumps.
rcp
Use rcp for core dumps.
tftp
Use TFTP for core dumps. This is the default.
Default
TFTP
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
CautionUse the exception commands only under the direction of a technical support representative. Creating a core dump while the router is functioning in a network can disrupt network operation. The resulting binary file, which is very large, must be transferred to a TFTP, FTP, or rcp server and subsequently interpreted by technical personnel who have access to source code and detailed memory maps.
If you use TFTP to dump the core file to a server, the router will only dump the first 16 MB of the core file. If the router's memory is larger than 16 MB, the whole core file will not be copied to the server. Therefore, use rcp or FTP to dump the core file.
Example
The following example configures a router to use FTP to dump a core file to the FTP server at 172.17.92.2 when it crashes:
ip ftp username redip ftp password blueexception protocol ftpexception dump 172.17.92.2Related Commands
exception core-file
exception dump
exception memory
ip ftp password
ip ftp usernamefair-queue
To enable weighted fair queueing for an interface, use the fair-queue interface configuration command. To disable weighted fair queueing for an interface, use the no form of this command.
fair-queue [congestive-discard-threshold [dynamic-queues [reservable-queues]]]
no fair-queueSyntax Description
Default
Fair queueing is enabled by default for physical interfaces whose bandwidth is less than or equal to 2.048 megabits per second (Mbps) and that do not use Link Access Procedure, Balanced (LAPB), X.25, or Synchronous Data Link Control (SDLC) encapsulations. (Fair queuing is not an option for these protocols.) However, if custom queuing or priority queuing is enabled for a qualifying link, it overrides fair queueing, effectively disabling it. Additionally, fair queuing is automatically disabled if you enable autonomous or SSE switching.
Fair queueing is disabled automatically on interfaces configured with the ppp multlilink command. If the no ppp multilink command is configured, you must enable fair queuing manually on the interface.
Congestive-discard-threshold: 64 messages; dynamic-queues: 256; reservable-queues: 0.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.0.
Note
When enabled for an interface, weighted fair queueing provides traffic priority management that automatically sorts among individual traffic streams without requiring that you first define access lists. Enabling weighted fair queueing requires use of this command only.
Weighted fair queuing can manage duplex data streams, such as those between pairs of applications, and simplex data streams such as voice or video. From the perspective of weighted fair queueing, there are two categories of sessions: high-bandwidth sessions and low-bandwidth sessions. Low-bandwidth traffic has effective priority over high-bandwidth traffic, and high-bandwidth traffic shares the transmission service proportionally according to assigned weights.
When weighted fair queuing is enabled for an interface, new messages for high-bandwidth traffic streams are discarded after the configured or default congestive-messages threshold has been met. However, low-bandwidth conversations, which include control-message conversations, continue to enqueue data. As a result, the fair queue may occasionally contain more messages than its configured threshold number specifies.
Weighted fair queuing uses a traffic data stream discrimination registry service to determine which traffic stream a message belongs to. For each forwarding protocol, shows the attributes of a message that are used to classify traffic into data streams.
It is important to note that IP precedence, congestion in Frame Relay switching, and discard eligibility flags affect the weights used for queuing.
IP precedence, which is set by the host or by policy maps, is a number in the range of 0 to 7. Data streams of precedence number are weighted so that they are given an effective bit rate of number+1 times as fast as a data stream of precedence 0, which is normal.
In Frame Relay switching, message flags for congestion (FECN and BECN) and discard eligible (DE) message flags cause the algorithm to select weights that effectively impose reduced queue priority, providing the application with "slow down" feedback and sorting traffic, giving the best service to applications within their Committed Information Rate.
Fair queuing is supported for all LAN and line (WAN) protocols except X.25. These protocols are listed in "Default." Because tunnels are software interfaces that are themselves routed over physical interfaces, fair queuing is not supported for tunnels. Fair queuing is on by default for interfaces with bandwidth less than or equal to 2 Mbps.
Note
When Resource Reservation Protocol (RSVP) is configured on an interface that supports fair queuing or on an interface that is configured for fair queuing with the reservable queues set to 0 (the default), the reservable queue size is automatically configured using the following method: interface bandwidth divided by 32 kbps. You can override this be specifying a reservable queue other than 0. For more information on RSVP, refer to the "Configuring IP Routing" chapter in the Network Protocols Configuration Guide, Part 1.
Examples
The following example enables use of weighted fair queuing on Serial 0, with a congestive threshold of 300. This means that messages will be discarded from the queuing system only when 300 or more messages have been queued and the message is in a data stream that has more than one message in the queue. The transmit queue limit is set to 2, based on the 384-kilobit (kb) line set by the bandwidth command:
interface serial 0bandwidth 384fair-queue 300The following example requests a fair queue with 512 dynamic queues, 18 RSVP queues, and a congestive discard threshold of 64 messages:
interface Serial 3/0ip unnumbered Ethernet 0/0fair-queue 64 512 18Related Commands
A dagger (†) indicates that the command is documented outside this chapter.
custom-queue-list
ip rsvp bandwidth †
priority-group
priority-list default
queue-list default
random-detect
show interface †filter-for-history
To define the type of information kept in the history table for the response time reporter probe, use the filter-for-history response time reporter configuration command. Use the no form of this command to return to the default value.
filter-for-history {none | all | overThreshold | failures}
no filter-for-history {none | all | overThreshold | failures}Syntax Description
Default
none
Command Mode
Response time reporter configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Use the filter-for-history command to control what gets stored in the history table for the response time reporter. To control how much history gets saved in the history table, use the lives-of-history-kept, buckets-of-history-kept, and the samples-of-history-kept response time reporter configuration commands.
A probe can collect history and capture statistics. 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 command to collect history.
Note
Example
In the following example, only probe packets that fail are kept in the history table:
rtr 1type echo protocol ipIcmpEcho 172.16.161.21lives-of-history-kept 1filter-for-history failuresRelated Commands
buckets-of-history-kept
lives-of-history-kept
rtr
samples-of-history-keptfrequency
To set the rate at which the response time reporter probe starts a response time operation, use the frequency response time reporter configuration command. Use the no form of this command to return to the default value.
frequency second
no frequencySyntax Description
second
Number of seconds between the probe's response time reporter operations. The default value is 60 seconds.
Default
60 seconds
Command Mode
Response time reporter configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
CautionFor normal operation, do not set the frequency value to less than 60 seconds for the following reasons: It is not needed when keeping statistics (the default), and it can slow down the WAN because of the potential overhead that numerous probes can cause.
If the probe takes longer to execute the current response time reporter operation than the specified frequency value, a statistics counter called busy is incremented in lieu of starting a second operation.
The value specified for the frequency command cannot be less than the value specified for the timeout response time reporter configuration command.
Example
In the following example, the probe is configured to execute a response time reporter operation every 90 seconds:
rtr 1type echo protocol ipIcmpEcho 172.16.1.176frequency 90Related Commands
hops-of-statistics-kept
To set the number of hops for which statistics are maintained per path for the response time reporter probe, use the hops-of-statistics-kept response time reporter configuration command. Use the no form of this command to return to the default value.
hops-of-statistics-kept size
no hops-of-statistics-keptSyntax Description
size
Number of hops for which statistics are maintained per path. The default is 16 hops for type pathEcho and 1 hop for type echo.
Default
16 hops for type pathEcho
1 hop for type echo
Command Mode
Response time reporter configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
One hop is the passage of a timed packet from this router to another network device. The other network device (is assumed to) be a device along the path to the destination (including the destination) when the probe type is pathEcho, or just the destination when the type is echo.
When the number of hops reaches the size specified, no further hop information is stored.
Example
In the following example, probe 2's statistics are maintained for only 10 hops:
rtr 2type pathecho protocol ipIcmpEcho 172.16.1.177hops-of-statistics-kept 10Related Commands
distributions-of-statistics-kept
hours-of-statistics-kept
paths-of-statistics-kept
rtr
statistics-distribution-intervalhostname
To specify or modify the host name for the network server, use the hostname global configuration command. The host name is used in prompts and default configuration filenames. The setup command facility also prompts for a host name at startup.
hostname name
Syntax Description
Default
The factory-assigned default host name is router.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The order of display at startup is banner message-of-the-day (MOTD), then login and password prompts, then EXEC banner.
Do not expect case to be preserved. Upper- and lowercase characters look the same to many internet software applications (often under the assumption that the application is doing you a favor). It may seem appropriate to capitalize a name the same way you might do in English, but conventions dictate that computer names appear all lowercase. For more information, refer to RFC 1178, Choosing a Name for Your Computer.
The name must also follow the rules for ARPANET host names. They must start with a letter, end with a letter or digit, and have as interior characters only letters, digits, and hyphens. Names must be 63 characters or fewer. For more information, refer to RFC 1035, Domain Names—Implementation and Specification.
Example
The following example changes the host name to sandbox:
hostname sandboxhours-of-statistics-kept
To set the number of hours for which statistics are maintained for the response time reporter probe, use the hours-of-statistics-kept response time reporter configuration command. Use the no form of this command to return to the default value.
hours-of-statistics-kept hours
no hours-of-statistics-keptSyntax Description
Default
2 hours
Command Mode
Response time reporter configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
When the number of hours exceeds the specified value, the statistics table wraps (that is, the oldest information is replaced by newer information).
Example
In the following example, probe 2's statistics are maintained for 3 hours:
rtr 2type pathecho protocol ipIcmpEcho 172.16.1.177hours-of-statistics-kept 3Related Commands
distributions-of-statistics-kept
hops-of-statistics-kept
paths-of-statistics-kept
rtr
statistics-distribution-intervalip bootp server
To access the BOOTP service available from hosts on the network, use the ip bootp server global configuration command. Use the no form of the command to disable these services.
ip bootp server
no ip bootp serverSyntax Description
This command has no arguments or keywords.
Default
Enabled
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
By default, the BOOTP server is enabled.
When you disable the BOOTP server, access to the BOOTP ports cause the Cisco IOS software to send an "ICMP port unreachable" message to the sender and discard the original incoming packet.
Note
Example
The following example disables the BOOTP service on the router:
no ip bootp serverip ftp passive
To configure the router to use only passive FTP connections, use the ip ftp passive global configuration command. To allow all types of FTP connections, use the no form of this command.
ip ftp passive
no ip ftp passiveSyntax Description
This command has no arguments or keywords.
Default
All types of FTP connections are allowed.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
Example
The following example configures the router to use only passive FTP connections:
ip ftp passiveRelated Commands
ip ftp password
ip ftp source-interface
ip ftp usernameip ftp password
To specify the password to be used for FTP connections, use the ip ftp password global configuration command. Use the no form of this command to return the password to its default.
ip ftp password [type] password
no ip ftp passwordSyntax Description
type
(Optional) Type of encryption to use on the password. A value of 0 disables encryption. A value of 7 indicates proprietary encryption.
password
Password to use for FTP connections.
Default
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.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
Example
The following example configures the router to use the username red and the password blue for FTP connections:
ip ftp username redip ftp password blueRelated Commands
ip ftp passive
ip ftp source-interface
ip ftp username
ip ftp source-interface
To specify the source IP address for FTP connections, use the ip ftp source-interface global configuration command. Use the no form of this command to use the address of the interface where the connection is made.
ip ftp source-interface interface
no ip ftp source-interfaceSyntax Description
Default
The FTP source address is the the IP address of the interface the FTP packets use to leave the router.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
Use this command to set the same source address for all FTP connections.
Example
The following example configures the router to use the IP address associated with the Ethernet 0 interface as the source address on all FTP packets, regardless of which interface is actually used to transmit the packet:
ip ftp source-interface ethernet 0Related Commands
ip ftp passive
ip ftp password
ip ftp usernameip ftp username
To configure the username for FTP connections, use the ip ftp username global configuration command. To configure the router to attempt anonymous FTP, use the no form of this command.
ip ftp username username
no ip ftp usernameSyntax Description
Default
The Cisco IOS software attempts an anonymous FTP.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
The remote username must be associated with an account on the destination server.
Example
The following example configures the router to use the username red and the password blue for FTP connections:
ip ftp username redip ftp password blueRelated Commands
ip ftp passive
ip ftp password
ip ftp source-interfaceip telnet source-interface
Use the ip telnet source-interface global configuration command to allow a user to select an address of an interface as the source address for Telnet connections.
ip telnet source-interface interface
no ip telnet source-interfaceSyntax Description
Default
The address of the closest interface to the destination as the source address. If the selected interface is not "up," the Cisco IOS software selects the address of the closest interface to the destination as the source address.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
Use this command to set an interface's IP address as the source for all telnet connections.
Example
The following example makes the IP address for interface Ethernet 1 as the source address for telnet connections:
ip telnet source-interface e 1Related Commands
A dagger (†) indicates that the command is documented outside this chapter.
ip tacacs source-interface †
ip tftp source-interface
ip radius source-interface †ip tftp source-interface
Use the ip tftp source-interface global configuration command to allow a user to select the interface whose address will be used as the source address for TFTP connections.
ip tftp source-interface interface
no ip tftp source-interfaceSyntax Description
Default
The address of the closest interface to the destination as the source address. If the selected interface is not "up," the Cisco IOS software selects the address of the closest interface to the destination as the source address.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
Use this command to set an interface's IP address as the source for all TFTP connections.
Example
The following example makes the IP address for interface Ethernet 1 as the source address for TFTP connections:
ip tftp source-interface e 1Related Commands
A dagger (†) indicates that the command is documented outside this chapter.
ip radius source-interface †
ip tacacs source-interface †
ip telnet source-interfacelives-of-history-kept
To set the number of lives maintained in the history table for the response time reporter probe, use the lives-of-history-kept response time reporter configuration command. Use the no form of this command to return to the default value.
lives-of-history-kept lives
no lives-of-history-keptSyntax Description
Default
0 lives
Command Mode
Response time reporter configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
The default value (0 lives) means that history is not collected for the probe. To disable history collection, use the default value for the lives-of-history-kept command rather than use the filter-for-history none response time reporter configuration command because the lives-of-history-kept command disables history collection before the probe's operation is attempted and the filter-for-history command checks for history inclusion after the probe's operation attempt is made.
When the number of lives exceeds the specified value, the history table wraps (that is, the oldest information is replaced by newer information).
When a probe makes a transition from pending to active, a life starts. When a probe's life ends, the probe makes a transition from active to pending.
Example
In the following example, probe 1's history is maintained for 5 lives:
rtr 1type echo protocol ipIcmpEcho 172.16.1.176lives-of-history-kept 5Related Commands
buckets-of-history-kept
filter-for-history
rtr
samples-of-history-keptload-interval
To change the length of time for which data is used to compute load statistics, use the load-interval interface configuration command. Use the no form of this command to revert to the default setting.
load-interval seconds
no load-interval secondsSyntax Description
seconds
Length of time for which data is used to compute load statistics. A value that is a multiple of 30, from 30 to 600 (30, 60, 90, 120, and so forth).
Default
300 seconds (or 5 minutes)
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
If you want load computations to be more reactive to short bursts of traffic, rather than averaged over five-minute periods, you can shorten the length of time over which load averages are computed.
If the load interval is set to thirty seconds, new data is used for load calculations over a thirty-second period. This data is used to compute load statistics, including input rate in bits and packets per second, output rate in bits and packets per second, load, and reliability.
Load data is gathered every five seconds. This data is used for a weighted average calculation in which more-recent load data has more weight in the computation than older load data. If the load interval is set to thirty seconds, the average is computed for the last thirty seconds of load data.
The load-interval command allows you to change the default interval of five minutes to a shorter or longer period of time. If you change it to a shorter period of time, the input and output statistics that are displayed when you use the show interface command will be more current, and based on more instantaneous data, rather than reflecting a more average load over a longer period of time.
This command is often used for dial backup purposes, to increase or decrease the likelihood of a backup interface being implemented, but it can be used on any interface.
Example
In the following example, the default five-minute average is set it to a thirty-second average. A burst in traffic that would not trigger a dial backup for an interface configured with the default five-minute interval might trigger a dial backup for this interface that is set for a shorter, thirty-second interval.
interface serial 0load-interval 30Related Command
A dagger (†) indicates that the command is documented outside this chapter.
show interfaces †
logging
To log messages to a syslog server host, use the logging global configuration command. The no form of this command deletes the syslog server with the specified address from the list of syslogs.
logging host
no logging hostSyntax Description
Default
No messages are logged to a syslog server host.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command identifies a syslog server host to receive logging messages. By issuing this command more than once, you build a list of syslog servers that receive logging messages.
Example
The following example logs messages to a host named johnson:
logging johnsonRelated Commands
logging trap
service timestampslogging buffered
To log messages to an internal buffer, use the logging buffered global configuration command. The no form of this command cancels the use of the buffer. The default form of this command returns the buffer size to the default size.
logging buffered [size]
no logging buffered
default logging bufferedSyntax Description
size
(Optional) Size of the buffer from 4096 to 4294967295 bytes. The default size varies by platform.
Default
For most platforms, the Cisco IOS software logs messages to the internal buffer.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command copies logging messages to an internal buffer. The buffer is circular in nature, so newer messages overwrite older messages after the buffer is filled.
To display the messages that are logged in the buffer, use the EXEC command show logging. The first message displayed is the oldest message in the buffer.
Do not make the buffer size too large because the router could run out of memory for other tasks. You can use the show memory EXEC command to view the free processor memory on the router; however, this is the maximum available and should not be approached. The command default logging buffered resets the buffer size to the default for the platform.
Example
The following example illustrates how to enable logging to an internal buffer:
logging bufferedRelated Commands
logging console
To limit messages logged to the console based on severity, use the logging console global configuration command. The no form of this command disables logging to the console terminal.
logging console level
no logging consoleSyntax Description
level
Limits the logging of messages displayed on the console terminal to a specified level. See for a list of the level keywords.
Default
debugging
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Specifying a level causes messages at that level and numerically lower levels to be displayed at the console terminal.
The EXEC command show logging displays the addresses and levels associated with the current logging setup, as well as any other logging statistics.
The effect of the log keyword with the IP access list (extended) command depends on the setting of the logging console command. The log keyword takes effect only if the logging console level is set to 6 or 7. If you change the default to a level lower than 6 and specify the log keyword with the IP access list (extended) command, no information is logged or displayed.
Example
The following example changes the level of messages displayed to the console terminal to alerts, which means alerts and emergencies are displayed:
logging console alertsRelated Commands
A dagger (†) indicates that the command is documented outside this chapter.
logging facility
access-list (extended) †logging facility
To configure the syslog facility in which error messages are sent, use the logging facility global configuration command. To revert to the default of local7, use the no form of this command.
logging facility facility-type
no logging facilitySyntax Description
Default
local7
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
describes the acceptable options for the facility-type keyword.
Example
The following example configures the syslog facility to kernel:
logging facility kernRelated Command
logging history
To limit syslog messages sent to the router's history table and the SNMP network management station based on severity, use the logging history global configuration command. The no form of this command returns the logging of syslog messages to the default level.
logging history level
no logging historySyntax Description
level
Limits the messages saved in the history table and sent to the SNMP network management station to the specified set of levels. See for a list of the level keywords.
Default
warnings, errors, critical, alerts, and emergencies messages
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Sending syslog messages to the SNMP network management station occurs when you enable syslog traps with the snmp-server enable trap global configuration command. Because SNMP traps are inherently unreliable and much too important to lose, at least one syslog message, the most recent message, is stored in a history table on the router. The number of messages stored in the table is governed by the logging history size command.
Specifying a level causes messages at that severity level and numerically lower levels to be stored in the router's history table and sent to the SNMP network management station. Severity levels are numbered 1 to 8 with 1 being the most important message and 8 being the least important message (that is, the lower the number, the more critical the message). For example, specifying the level critical causes critical (3), alerts (2), and emergencies (1) messages to be stored to the history table and sent to the SNMP network management station. See for a list of severity levels.
The EXEC command show logging history displays information about the history table such as the table size, the status of messages, and text of the messages stored in the table.
Example
The following example changes the level of messages sent to the history table and to the SNMP server to alerts, which means alerts (2) and emergencies (1) are sent:
logging history alertsRelated Commands
logging history size
show logging
snmp-server enablelogging history size
To change the number of syslog messages stored in the router's history table, use the logging history size global configuration command. The no form of this command returns the number of messages to the default value.
logging history size number
no logging history sizeSyntax Description
number
Number from 1 to 500 that indicates the maximum number of messages stored in the history table.
Default
1 message
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
When the history table is full (that is, it contains the maximum number of message entries specified with the logging history size command), the oldest message entry is deleted from the table to allow the new message entry to be stored.
Example
The following example sets the number of messages stored in the history table to 20:
logging history size 20Related Commands
logging monitor
To limit messages logged to the terminal lines (monitors) based on severity, use the logging monitor global configuration command. This command limits the logging messages displayed on terminal lines other than the console line to messages with a level at or above level. The no form of this command disables logging to terminal lines other than the console line.
logging monitor level
no logging monitorSyntax Description
Default
debugging
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Specifying a level causes messages at that level and numerically lower levels to be displayed to the monitor.
Example
The following example specifies that only messages of the levels errors, critical, alerts, and emergencies be displayed on terminals:
logging monitor errorsRelated Command
A dagger (†) indicates that the command is documented outside this chapter.
terminal monitor †
logging on
To control logging of error messages, use the logging on global configuration command. This command sends debug or error messages to a logging process, which logs messages to designated locations asynchronously to the processes that generated the messages. The no form of this command disables the logging process.
logging on
no logging onSyntax Description
This command has no arguments or keywords.
Default
The Cisco IOS software sends messages to the asynchronous logging process.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The logging process controls the distribution of logging messages to the various destinations, such as the logging buffer, terminal lines, or syslog server. You can turn logging on and off for these destinations individually using the logging buffered, logging monitor, and logging commands. However, if the logging on command is disabled, no messages will be sent to these destinations. Only the console will receive messages.
Additionally, the logging process logs messages to the console and the various destinations after the processes that generated them have completed. When the logging process is disabled, messages are displayed on the console as soon as they are produced, often appearing in the middle of command output.
CautionDisabling the logging on command will significantly slow down the router. Any process generating debug or error messages will wait until the messages have been displayed on the console before continuing.
The logging synchronous command also affects the displaying of messages to the console. When the logging synchronous command is enabled, messages will only appear after the user types a carriage return.
Examples
The following example shows command output and message output when logging is enabled. The ping process finishes before any of the logging information is printed to the console (or any other destination).
Router(config)# logging onRouter(config)# endRouter#%SYS-5-CONFIG_I: Configured from console by consoleRouter# ping dirtType escape sequence to abort.Sending 5, 100-byte ICMP Echos to 172.16.1.129, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5), round-trip min/avg/max = 4/5/8 msRouter#IP: s=172.21.96.41 (local), d=172.16.1.129 (Ethernet1/0), len 100, sendingIP: s=171.69.1.129 (Ethernet1/0), d=172.21.96.41, len 114, rcvd 1IP: s=172.21.96.41 (local), d=172.16.1.129 (Ethernet1/0), len 100, sendingIP: s=171.69.1.129 (Ethernet1/0), d=172.21.96.41, len 114, rcvd 1IP: s=172.21.96.41 (local), d=172.16.1.129 (Ethernet1/0), len 100, sendingIP: s=171.69.1.129 (Ethernet1/0), d=172.21.96.41, len 114, rcvd 1IP: s=172.21.96.41 (local), d=172.16.1.129 (Ethernet1/0), len 100, sendingIP: s=171.69.1.129 (Ethernet1/0), d=172.21.96.41, len 114, rcvd 1IP: s=172.21.96.41 (local), d=172.16.1.129 (Ethernet1/0), len 100, sendingIP: s=171.69.1.129 (Ethernet1/0), d=172.21.96.41, len 114, rcvd 1In the next example, logging is disabled. The message output is displayed as messages are generated, causing the debug messages to be interspersed with "Type escape sequence to abort."
Router(config)# no logging onRouter(config)# end%SYS-5-CONFIG_I: Configured from console by consoleRouter#Router# ping dirtIP: s=172.21.96.41 (local), d=172.16.1.129 (Ethernet1/0), len 100, sendingTypIP: s=171.69.1.129 (Ethernet1/0), d=172.21.96.41, len 114, rcvd 1eIP: s=172.21.96.41 (local), d=172.16.1.129 (Ethernet1/0), len 100, sending escIP: s=171.69.1.129 (Ethernet1/0), d=172.21.96.41, len 114, rcvd 1IP: s=172.21.96.41 (local), d=172.16.1.129 (Ethernet1/0), len 100, sendingapeIP: s=171.69.1.129 (Ethernet1/0), d=172.21.96.41, len 114, rcvd 1IP: s=172.21.96.41 (local), d=172.16.1.129 (Ethernet1/0), len 100, sendingseIP: s=171.69.1.129 (Ethernet1/0), d=172.21.96.41, len 114, rcvd 1IP: s=172.21.96.41 (local), d=172.16.1.129 (Ethernet1/0), len 100, sendingquenIP: s=171.69.1.129 (Ethernet1/0), d=172.21.96.41, len 114, rcvd 1ce to abort.Sending 5, 100-byte ICMP Echos to 172.16.1.129, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5), round-trip min/avg/max = 152/152/156 msRouter#Related Commands
logging
logging buffered
logging monitor
logging synchronouslogging source-interface
To specify the source IP address of syslog packets, use the logging source-interface global configuration command. Use the no form of this command to remove the source designation.
logging source-interface type number
no logging source-interfaceSyntax Description
Default
No interface is specified.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Normally, a syslog message contains the IP address of the interface it uses to leave the router. The logging source-interface command specifies that syslog packets contain the IP address of a particular interface, regardless of which interface the packet uses to exit the router.
Examples
The following example specifies that the IP address for Ethernet interface 0 is the source IP address for all syslog messages:
logging source-interface ethernet 0The following example specifies that the IP address for Ethernet interface 2/1 on a Cisco 7000 is the source IP address for all syslog messages:
logging source-interface ethernet 2/1logging synchronous
To synchronize unsolicited messages and debug output with solicited Cisco IOS software output and prompts for a specific console port line, auxiliary port line, or virtual terminal line, use the logging synchronous line configuration command. Use the no form of this command to disable synchronization of unsolicited messages and debug output.
logging synchronous [level severity-level | all] [limit number-of-buffers]
no logging synchronous [level severity-level | all] [limit number-of-buffers]Syntax Description
Defaults
This feature is turned off by default.
If you do not specify a severity level, the default value of 2 is assumed.
If you do not specify the maximum number of buffers to be queued, the default value of 20 is assumed.
Command Mode
Line configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
When synchronous logging of unsolicited messages and debug output is turned on, unsolicited Cisco IOS software output is displayed on the console or printed after solicited Cisco IOS software output is displayed or printed. Unsolicited messages and debug output is displayed on the console after the prompt for user input is returned. This is to keep unsolicited messages and debug output from being interspersed with solicited software output and prompts. After the unsolicited messages are displayed, the console displays the user prompt again.
When specifying a severity level number, consider that for the logging system, low numbers indicate greater severity and high numbers indicate lesser severity.
When a terminal line's message-queue limit is reached, new messages are dropped from the line, although these messages might be displayed on other lines. If messages are dropped, the notice "%SYS-3-MSGLOST number-of-messages due to overflow" follows any messages that are displayed. This notice is displayed only on the terminal that lost the messages. It is not sent to any other lines, any logging servers, or the logging buffer.
CautionBy configuring abnormally large message-queue limits and setting the terminal to "terminal monitor" on a terminal that is accessible to intruders, you expose yourself to "denial of service" attacks. An intruder could carry out the attack by putting the terminal in synchronous output mode, making a Telnet connection to a remote host, and leaving the connection idle. This could cause large numbers of messages to be generated and queued, and these messages would consume all available RAM. Although unlikely to occur, you should guard against this type of attack through proper configuration.
Example
The following example identifies line 4 and enables synchronous logging for line 4 with a severity level of 6. Then the example identifies another line, line 2, and enables synchronous logging for line 2 with a severity level of 7 and specifies a maximum number of buffers to be 70000:
line 4 logging synchronous level 6line 2logging synchronous level 7 limit 70000Related Commands
A dagger (†) indicates that the command is documented outside this chapter.
line †
logging onlogging trap
To limit messages logged to the syslog servers based on severity, use the logging trap global configuration command. The command limits the logging of error messages sent to syslog servers to only those messages at the specified level. Use the no form of this command to disable logging to syslog servers.
logging trap level
no logging trapSyntax Description
Default
Informational
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The EXEC command show logging displays the addresses and levels associated with the current logging setup. The command output also includes ancillary statistics.
lists the syslog definitions that correspond to the debugging message levels. Additionally, there are four categories of messages generated by the software, as follows:
•
•
•
•
Use the logging and logging trap commands to send messages to a UNIX syslog server.
Example
The following example logs messages to a host named johnson:
logging johnson logging trap notificationsRelated Command
ntp access-group
To control access to the system's Network Time Protocol (NTP) services, use the ntp access-group global configuration command. To remove access control to the system's NTP services, use the no form of this command.
ntp access-group {query-only | serve-only | serve | peer} access-list-number
no ntp access-group {query-only | serve-only | serve | peer}Syntax Description
Default
No access control (full access granted to all systems)
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The access group options are scanned in the following order from least restrictive to most restrictive:
1
2
3
4
Access is granted for the first match that is found. If no access groups are specified, all access is granted to all sources. If any access groups are specified, only the specified access is granted. This facility provides minimal security for the time services of the system. However, it can be circumvented by a determined programmer. If tighter security is desired, use the NTP authentication facility.
Example
In the following example, the system is configured to allow itself to be synchronized by a peer from access list 99. However, the system restricts access to allow only time requests from access list 42.
ntp access-group peer 99ntp access-group serve-only 42Related Command
A dagger (†) indicates that the command is documented outside this chapter.
access-list †
ntp authenticate
To enable Network Time Protocol (NTP) authentication, use the ntp authenticate global configuration command. Use the no form of this command to disable the feature.
ntp authenticate
no ntp authenticateSyntax Description
This command has no keywords or arguments.
Default
No authentication
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Use this command if you want authentication. If this command is specified, the system will not synchronize to a system unless it carries one of the authentication keys specified in the ntp trusted-key command.
Example
The following example enables NTP authentication:
ntp authenticateRelated Commands
ntp authentication-key
ntp trusted-keyntp authentication-key
To define an authentication key for Network Time Protocol (NTP), use the ntp authentication-key global configuration command. Use the no form of this command to remove the authentication key for NTP.
ntp authentication-key number md5 value
no ntp authentication-key numberSyntax Description
Default
No authentication key is defined for NTP.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Use this command to define authentication keys for use with other NTP commands in order to provide a higher degree of security.
Note
Example
The following example sets authentication key 10 to aNiceKey:
ntp authentication-key 10 md5 aNiceKeyRelated Commands
ntp authenticate
ntp peer
ntp server
ntp trusted-keyntp broadcast
To specify that a specific interface should send Network Time Protocol (NTP) broadcast packets, use the ntp broadcast interface configuration command. Use the no form of this command to disable this capability.
ntp broadcast [version number]
no ntp broadcastSyntax Description
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
In the following example, Ethernet interface 0 is configured to send NTP version 2 packets:
interface ethernet 0ntp broadcast version 2Related Commands
ntp broadcast client
ntp broadcastdelayntp broadcast client
To allow the system to receive NTP broadcast packets on an interface, use the ntp broadcast client command. Use the no form of this command to disable this capability.
ntp broadcast client
no ntp broadcast clientSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Use this command to allow the system to listen to broadcast packets on an interface-by-interface basis.
Example
In the following example, the Cisco IOS software synchronizes to NTP packets broadcast on Ethernet interface 1:
interface ethernet 1ntp broadcast clientRelated Commands
ntp broadcast
ntp broadcastdelayntp broadcastdelay
To set the estimated round-trip delay between the Cisco IOS software and a Network Time Protocol (NTP) broadcast server, use the ntp broadcastdelay global configuration command. Use the no form of this command to revert to the default value.
ntp broadcastdelay microseconds
no ntp broadcastdelaySyntax Description
microseconds
Estimated round-trip time (in microseconds) for NTP broadcasts. The range is from 1 to 999999.
Default
3000 microseconds
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Use this command when the router is configured as a broadcast client and the round-trip delay on the network is other than 3000 microseconds.
Example
In the following example, the estimated round-trip delay between a router and the broadcast client is set to 5000 microseconds:
ntp broadcastdelay 5000Related Commands
ntp broadcast
ntp broadcast clientntp clock-period
CautionDo not enter this command; it is documented for informational purposes only. The system automatically generates this command as Network Time Protocol (NTP) determines the clock error and compensates.
As NTP compensates for the error in the system clock, it keeps track of the correction factor for this error. The system automatically saves this value into the system configuration using the ntp clock-period global configuration command. The system uses the no form of this command to revert to the default.
ntp clock-period value
no ntp clock-periodSyntax Description
Default
17179869 (4 milliseconds)
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
If a copy running-config startup-config command is entered to save the configuration to NVRAM, this command will automatically be added to the configuration. It is a good idea to perform this task after NTP has been running for a week or so; this will help NTP synchronize more quickly if the system is restarted.
ntp disable
To prevent an interface from receiving Network Time Protocol (NTP) packets, use the ntp disable interface configuration command. To enable receipt of NTP packets on an interface, use the no form of this command.
ntp disable
no ntp disableSyntax Description
This command has no arguments or keywords.
Default
Enabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command provides a simple method of access control.
Example
In the following example, Ethernet interface 0 is prevented from receiving NTP packets:
interface ethernet 0ntp disablentp master
To configure the Cisco IOS software as a Network Time Protocol (NTP) master clock to which peers synchronize themselves when an external NTP source is not available, use the ntp master global configuration command. To disable the master clock function, use the no form of this command.
ntp master [stratum]
no ntp master [stratum]
CautionUse this command with extreme caution. It is very easy to override valid time sources using this command, especially if a low stratum number is configured. Configuring multiple machines in the same network with the ntp master command can cause instability in keeping time if the machines do not agree on the time.
Syntax Description
stratum
(Optional) Number from 1 to 15. Indicates the NTP stratum number that the system will claim.
Default
By default, the master clock function is disabled. When enabled, the default stratum is 8.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Because Cisco's implementation of NTP does not support directly attached radio or atomic clocks, the router is normally synchronized, directly or indirectly, to an external system that has such a clock. In a network without Internet connectivity, such a time source may not be available. The ntp master command is used in such cases.
If the system has ntp master configured, and it cannot reach any clock with a lower stratum number, the system will claim to be synchronized at the configured stratum number, and other systems will be willing to synchronize to it via NTP.
Note
Example
In the following example, a router is configured as an NTP master clock to which peers may synchronize:
ntp master 10Related Command
ntp peer
To configure the system clock to synchronize a peer or to be synchronized by a peer, use the
ntp peer global configuration command. To disable this capability, use the no form of this command.ntp peer ip-address [version number] [key keyid] [source interface] [prefer]
no ntp peer ip-addressSyntax Description
Default
No peers are configured by default. If a peer is configured, the default NTP version number is 3, no authentication key is used, and the source IP address is taken from the outgoing interface.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Use this command if you want to allow this machine to synchronize with the peer, or vice versa. Using the prefer keyword reduces switching back and forth between peers.
If you are using the default version of 3 and NTP synchronization does not occur, try using NTP version number 2. Many NTP servers on the Internet run version 2.
Example
In the following example, a router is configured to allow its system clock to be synchronized with the clock of the peer (or vice versa) at IP address 192.168.22.33 using NTP version 2. The source IP address is the address of Ethernet 0.
ntp peer 192.168.22.33 version 2 source ethernet 0Related Commands
ntp authentication-key
ntp server
ntp sourcentp server
To allow the system clock to be synchronized by a time server, use the ntp server global configuration command. To disable this capability, use the no form of this command.
ntp server ip-address [version number] [key keyid] [source interface] [prefer]
no ntp server ip-addressSyntax Description
Default
No peers are configured by default. If a peer is configured, the default NTP version number is 3, no authentication key is used, and the source IP address is taken from the outgoing interface.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Use this command if you want to allow this machine to synchronize with the specified server. The server will not synchronize to this machine.
Using the prefer keyword reduces switching back and forth between servers.
If you are using the default version of 3 and NTP synchronization does not occur, try using NTP version number 2. Many NTP servers on the Internet run version 2.
Example
In the following example, a router is configured to allow its system clock to be synchronized with the clock of the peer at IP address 172.16.22.44 using NTP version 2:
ntp server 172.16.22.44 version 2Related Commands
ntp authentication-key
ntp peer
ntp sourcentp source
To use a particular source address in Network Time Protocol (NTP) packets, use the ntp source global configuration command. Use the no form of this command to remove the specified source address.
ntp source type number
no ntp sourceSyntax Description
Default
Source address is determined by the outgoing interface.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Use this command when you want to use a particular source IP address for all NTP packets. The address is taken from the named interface. This command is useful if the address on an interface cannot be used as the destination for reply packets. If the source keyword is present on an ntp server or ntp peer command, that value overrides the global value.
Example
In the following example, a router is configured to use the IP address of Ethernet 0 as the source address of all outgoing NTP packets:
ntp source ethernet 0Related Commands
ntp trusted-key
To authenticate the identity of a system to which Network Time Protocol (NTP) will synchronize, use the ntp trusted-key global configuration command. Use the no form of this command to disable authentication of the identity of the system.
ntp trusted-key key-number
no ntp trusted-key key-numberSyntax Description
Default
Disabled
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
If authentication is enabled, use this command to define one or more key numbers (corresponding to the keys defined with the ntp authentication-key command) that a peer NTP system must provide in its NTP packets, in order for this system to synchronize to it. This provides protection against accidentally synchronizing the system to a system that is not trusted, since the other system must know the correct authentication key.
Example
In the following example, the system is configured to synchronize only to systems providing authentication key 42 in its NTP packets:
ntp authenticatentp authentication-key 42 md5 aNiceKeyntp trusted-key 42Related Commands
ntp authenticate
ntp authentication-keyntp update-calendar
To periodically update the Cisco 7000 series or Cisco 7200 series calendar from Network Time Protocol (NTP), use the ntp update-calendar global configuration command. Use the no form of this command to disable this feature.
ntp update-calendar
no ntp update-calendarSyntax Description
This command has no arguments or keywords.
Default
The calendar is not updated.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
If a Cisco 7000 or Cisco 7200 is synchronized to an outside time source via NTP, it is a good idea to periodically update the calendar with the time learned from NTP. Otherwise, the calendar will tend to gradually lose or gain time. The calendar will be updated only if NTP has synchronized to an authoritative time server.
Example
In the following example, the system is configured to periodically update the calendar from the system clock:
ntp update-calendarRelated Commands
clock read-calendar
clock update-calendarowner
To configure the SNMP owner of the response time reporter probe, use the owner response time reporter configuration command. Use the no form of this command to return to the default value.
owner text
no ownerSyntax Description
Default
No owner is specified.
Command Mode
Response time reporter configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
The owner name contains one or more of the following: ASCII form of the network management station's transport address, network management station name (that is, the domain name), and network management personnel's name, location, or phone number. In some cases, the agent itself will be the owner of the probe. In these cases, the name can begin with "agent."
Example
In the following example, probe 1's owner is set:
rtr 1type echo protocol ipIcmpEcho 172.16.1.176owner 172.16.1.189 cwb.cisco.com John Doe RTP 555-1212Related Command
paths-of-statistics-kept
To set the number of paths for which statistics are maintained per hour for the response time reporter probe, use the paths-of-statistics-kept response time reporter configuration command. Use the no form of this command to return to the default value.
paths-of-statistics-kept size
no paths-of-statistics-keptSyntax Description
size
Number of paths for which statistics are maintained per hour. The default is 5 paths for type pathEcho and 1 path for type echo.
Default
5 paths for type pathEcho
1 path for type echo
Command Mode
Response time reporter configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
A path is the route the probe's request packet takes through the network to get to its destination. The probe may take a different path to reach its destination for each response time reporter operation.
When the number of paths reaches the size specified, no further path information is stored.
Example
In the following example, probe 2's statistics are maintained for only 3 paths:
rtr 2type pathEcho protocol ipIcmpEcho 172.16.1.177paths-of-statistics-kept 3Related Commands
distributions-of-statistics-kept
hops-of-statistics-kept
hours-of-statistics-kept
rtr
statistics-distribution-intervalping (privileged)
Use the ping (packet internet groper) privileged EXEC command to diagnose basic network connectivity on Apollo, AppleTalk, Connectionless Network Service (CLNS), DECnet, IP, Novell IPX, VINES, or XNS networks.
ping [protocol] {host | address}
Syntax Description
protocol
(Optional) Protocol keyword, one of apollo, appletalk, clns, decnet, ip, ipx, vines, or xns.
host
Host name of system to ping.
address
Address of system to ping.
Command Mode
Privileged EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The ping program sends an echo request packet to an address, then awaits a reply. Ping output can help you evaluate path-to-host reliability, delays over the path, and whether the host can be reached or is functioning.
To abnormally terminate a ping session, type the escape sequence—by default, Ctrl-^ X. You type the default by simultaneously pressing and releasing the Ctrl, Shift, and 6 keys, and then pressing the X key.
describes the test characters that the ping facility sends.
Note
Example
After you enter the ping command in privileged mode, the system prompts for one of the following keywords: appletalk, clns, ip, novell, apollo, vines, decnet, or xns. The default protocol is IP.
If you enter a host name or address on the same line as the ping command, the default action is taken as appropriate for the protocol type of that name or address.
While the precise dialog varies somewhat from protocol to protocol, all are similar to the ping session using default values shown in the following display.
Router# pingProtocol [ip]:Target IP address: 192.168.7.27Repeat count [5]:Datagram size [100]:Timeout in seconds [2]:Extended commands [n]:Sweep range of sizes [n]:Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 192.168.7.27, timeout is 2 seconds:!!!!!Success rate is 100 percent, round-trip min/avg/max = 1/2/4 msdescribes the default ping fields shown in the display.
Related Command
ping (user)
Use the ping (packet internet groper) user EXEC command to diagnose basic network connectivity on AppleTalk, CLNS, IP, Novell, Apollo, VINES, DECnet, or XNS networks.
ping [protocol] {host | address}
Syntax Description
protocol
(Optional) Protocol keyword, one of apollo, appletalk, clns, decnet, ip, ipx, vines, or xns.
host
Host name of system to ping.
address
Address of system to ping.
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The user-level ping feature provides a basic ping facility for users who do not have system privileges. This feature allows the Cisco IOS software to perform the simple default ping functionality for a number of protocols. Only the terse form of the ping command is supported for user-level pings.
If the system cannot map an address for a host name, it returns an "%Unrecognized host or address" error message.
To abnormally terminate a ping session, type the escape sequence—by default, Ctrl-^ X. You type the default by simultaneously pressing and releasing the Ctrl, Shift, and 6 keys and then pressing the X key.
describes the test characters that the ping facility sends.
Example
The following display shows sample ping output when you ping the IP host named donald:
Router> ping donaldType escape sequence to abort.Sending 5, 100-byte ICMP Echos to 192.168.7.27, timeout is 2 seconds:!!!!!Success rate is 100 percent, round-trip min/avg/max = 1/3/4 msRelated Command
priority-group
To assign the specified priority list to an interface, use the priority-group interface configuration command. Use the no form of this command to remove the specified priority group assignment.
priority-group list
no priority-groupSyntax Description
Default
None
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Note
Only one list can be assigned per interface. Priority output queueing provides a mechanism to prioritize packets transmitted on an interface.
Use the show queuing priority and show interface commands to display the current status of the output queues.
Example
The following example causes packets on interface serial 0 to be classified by priority list 1:
interface serial 0 priority-group 1Related Commands
priority-list default
priority-list interface
priority-list queue-limit
promptpriority-list default
To assign a priority queue for those packets that do not match any other rule in the priority list, use the priority-list default global configuration command. Use the no form of this command to return to the default or assign normal as the default.
priority-list list-number default {high | medium | normal | low}
no priority-list list-number default {high | medium | normal | low}Syntax Description
list-number
Arbitrary integer between 1 and 16 that identifies the priority list selected by the user.
high | medium | normal | low
Priority queue level.
Default
The normal queue, if you use the no form of the command.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
When using multiple rules, remember that the system reads the priority-list commands in order of appearance. When classifying a packet, the system searches the list of rules specified by priority-list commands for a matching protocol or interface type. When a match is found, the packet is assigned to the appropriate queue. The list is searched in the order it is specified, and the first matching rule terminates the search.
Example
The following example sets the priority queue for those packets that do not match any other rule in the priority list to a low priority:
priority-list 1 default lowRelated Commands
priority-list interface
To establish queuing priorities on packets entering from a given interface, use the priority-list interface global configuration command. Use the no form of this command with the appropriate arguments to remove an entry from the list.
priority-list list-number interface interface-type interface-number {high | medium |
normal | low}
no priority-list list-number interface interface-type interface-number {high | medium |
normal | low}Syntax Description
Default
No queuing priorities are established.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
When using multiple rules, remember that the system reads the priority-list commands in order of appearance. When classifying a packet, the system searches the list of rules specified by priority-list commands for a matching protocol or interface type. When a match is found, the packet is assigned to the appropriate queue. The list is searched in the order it is specified, and the first matching rule terminates the search.
Example
The following example sets any packet type entering on Ethernet interface 0 to a medium priority:
priority-list 3 interface ethernet 0 mediumRelated Commands
priority-list protocol
To establish queuing priorities based upon the protocol type, use the priority-list protocol global configuration command. Use the no form of this command with the appropriate list number to remove an entry from the list.
priority-list list-number protocol protocol-name {high | medium | normal | low}
queue-keyword keyword-value
no priority-list list-number protocol [protocol-name {high | medium | normal | low}
queue-keyword keyword-value]Syntax Description
Default
No queuing priorities are established.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
When using multiple rules for a single protocol, remember that the system reads the priority settings in order of appearance. When classifying a packet, the system searches the list of rules specified by priority-list commands for a matching protocol or interface type. When a match is found, the packet is assigned to the appropriate queue. The list is searched in the order it is specified, and the first matching rule terminates the search.
The decnet_router-l1 keyword refers to the multicast address for all level-1 routers, which are intra-area routers, and the decnet_router-l2 keyword refers to all level 2 routers, which are interarea routers.
The dlsw, rsrb, and stun keywords refer only to direct encapsulation.
Use , , and to configure the queuing priorities for your system.
Table 71 Common UDP Services and Their Port Numbers
TFTP
69
NFS
2049
SNMP
161
RPC
111
DNS
53
Note
For some protocols, such as TFTP and FTP, only the initial request uses port 69. Subsequent packets use a randomly chosen port number. For these types of protocols, the use of port numbers fails to be an effective method to manage queued traffic.Use the no priority-list global configuration command followed by the appropriate list-number argument and the protocol keyword to remove a priority list entry assigned by protocol type.
Examples
The following example assigns 1 as the arbitrary priority list number, specifies DECnet as the protocol type, and assigns a high-priority level to the DECnet packets transmitted on this interface:
priority-list 1 protocol decnet highThe following example assigns a medium-priority level to every DECnet packet with a size greater than 200 bytes:
priority-list 2 protocol decnet medium gt 200The following example assigns a medium-priority level to every DECnet packet with a size less than 200 bytes:
priority-list 4 protocol decnet medium lt 200The following example assigns a high-priority level to traffic that matches IP access list 10:
priority-list 1 protocol ip high list 10The following example assigns a medium-priority level to Telnet packets:
priority-list 4 protocol ip medium tcp 23The following example assigns a medium-priority level to UDP Domain Name service packets:
priority-list 4 protocol ip medium udp 53The following example assigns a high-priority level to traffic that matches Ethernet type code access list 201:
priority-list 1 protocol bridge high list 201The following example assigns a high-priority level to DLSw+ traffic with TCP encapsulation:
priority-list 1 protocol ip high tcp 2065The following example assigns a high-priority level to DLSw+ traffic with Direct encapsulation:
priority-list 1 protocol dlsw highRelated Commands
priority-list queue-limit
To specify the maximum number of packets that can be waiting in each of the priority queues, use the priority-list queue-limit global configuration command.The no form of this command selects the normal queue.
priority-list list-number queue-limit high-limit medium-limit normal-limit low-limit
no priority-list list-number queue-limitSyntax Description
Default
The default queue limit arguments are listed in .
Table 72 Priority Queue Packet Limits
Limitshigh-limit
20
medium-limit
40
normal-limit
60
low-limit
80
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
If a priority queue overflows, excess packets are discarded and quench messages can be sent, if appropriate, for the protocol.
Example
The following example sets the maximum packets in the priority queue to 10:
priority-list 2 queue-limit 10 40 60 80Related Commands
prompt
To customize the prompt, use the prompt global configuration command. To revert to the default prompt, use the no form of this command.
prompt string
no prompt [string]Syntax Description
Default
The default prompt is either Router or the name defined with the hostname global configuration command, followed by an angle bracket (>) for EXEC mode or a pound sign (#) for privileged EXEC mode.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
You can include escape sequences when specifying the prompt. All escape sequences are preceded by a percent sign (%). lists the valid escape sequences.
Issuing the prompt%h command has the same effect as issuing the no prompt command.
Examples
The following example changes the EXEC prompt to include the TTY number, followed by the name and a space:
prompt TTY%n@%h%s%pThe following are examples of user and privileged EXEC prompts that result from the previous command:
TTY17@Router1 >TTY17SRouter1 #Related Command
queue-list default
To assign a priority queue for those packets that do not match any other rule in the queue list, use the queue-list default global configuration command. To restore the default value, use the no form of this command.
queue-list list-number default queue-number
no queue-list list-number default queue-numberSyntax Description
list-number
Number of the queue list. An integer from 1 to 16.
queue-number
Number of the queue. An integer from 1 to 16.
Default
Queue number 1
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
When using multiple rules, remember that the system reads the queue-list commands in order of appearance. When classifying a packet, the system searches the list of rules specified by queue-list commands for a matching protocol or interface type. When a match is found, the packet is assigned to the appropriate queue. The list is searched in the order it is specified, and the first matching rule terminates the search.
Queue number 0 is a system queue. It is emptied before any of the other queues are processed. The system enqueues high-priority packets, such as keepalives, to this queue.
Use the show interface command to display the current status of the output queues.
Example
In the following example, the default queue for list 10 is set to queue number 2:
queue-list 10 default 2Related Commands
custom-queue-list
show queueingqueue-list interface
To establish queuing priorities on packets entering on an interface, use the queue-list interface global configuration command. To remove an entry from the list, use the no form of the command.
queue-list list-number interface type number queue-number
no queue-list list-number interface queue-numberSyntax Description
Default
No queuing priorities are established.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
When using multiple rules, remember that the system reads the queue-list commands in order of appearance. When classifying a packet, the system searches the list of rules specified by queue-list commands for a matching protocol or interface type. When a match is found, the packet is assigned to the appropriate queue. The list is searched in the order it is specified, and the first matching rule terminates the search.
Example
In the following example, queue list 4 established queuing priorities for packets entering on interface tunnel 3. The queue number assigned is 10.
queue-list 4 interface tunnel 3 10Related Commands
custom-queue-list
show queueingqueue-list protocol
To establish queuing priority based upon the protocol type, use the queue-list protocol global configuration command. Use the no form of this command with the appropriate list number to remove an entry from the list.
queue-list list-number protocol protocol-name queue-number queue-keyword keyword-value
no queue-list list-number protocol protocol-nameSyntax Description
Default
No queuing priorities are established.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
When using multiple rules, remember that the system reads the queue-list commands in order of appearance. When classifying a packet, the system searches the list of rules specified by queue-list commands for a matching protocol or interface type. When a match is found, the packet is assigned to the appropriate queue. The list is searched in the order it is specified, and the first matching rule terminates the search.
The decnet_router-l1 keyword refers to the multicast address for all level-1 routers, which are intra-area routers, and the decnet_router-l2 keyword refers to all level 2 routers, which are interarea routers.
The dlsw, rsrb, and stun keywords refer only to direct encapsulation.
Use , , and from the priority-list protocol command to configure custom queuing for your system.
Examples
The following example assigns 1 as the custom queue list, specifies DECnet as the protocol type, and assigns 3 as a queue number to the packets transmitted on this interface:
queue-list 1 protocol decnet 3The following example assigns DECnet packets with a size greater than 200 bytes to queue number 2:
queue-list 2 protocol decnet 2 gt 200The following example assigns DECnet packets with a size less than 200 bytes to queue number 2:
queue-list 4 protocol decnet 2 lt 200The following example assigns traffic that matches IP access list 10 to queue number 1:
queue-list 1 protocol ip 1 list 10The following example assigns Telnet packets to queue number 2:
queue-list 4 protocol ip 2 tcp 23The following example assigns UDP Domain Name service packets to queue number 2:
queue-list 4 protocol ip 2 udp 53The following example assigns traffic that matches Ethernet type code access list 201 to queue number 1:
queue-list 1 protocol bridge 1 list 201Related Commands
custom-queue-list
show queueingqueue-list queue byte-count
To designate the byte size allowed per queue, use the queue-list queue byte-count global configuration command. To return the byte size to the default value, use the no form of the command.
queue-list list-number queue queue-number byte-count byte-count-number
no queue-list list-number queue queue-number byte-count byte-count-numberSyntax Description
Default
1500 bytes
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
In the following example, queue list 9 establishes the byte-count as 1400 for queue number 10:
queue-list 9 queue 10 byte-count 1400Related Commands
custom-queue-list
show queueingqueue-list queue limit
To designate the queue length limit for a queue, use the queue-list queue limit global configuration command. To return the queue length to the default value, use the no form of the command.
queue-list list-number queue queue-number limit limit-number
no queue-list list-number queue queue-number limit limit-numberSyntax Description
Default
20 entries
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
In the following example, the queue length of queue 10 is increased to 40:
queue-list 5 queue 10 limit 40Related Commands
custom-queue-list
show queueingrandom-detect
To enable random early detection on an interface, use the random-detect interface configuration command. Use the no form of this command to disable random early detection on the interface.
random-detect [weighting]
no random-detectSyntax Description
Default
Random early detection is disabled.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Random early detection (RED) is useful in high-speed TCP/IP networks to avoid congestion by dropping packets at a controlled rate. RED is not recommended for protocols, such as AppleTalk or Novell Netware, that respond to dropped packets by retransmitting the packets at the same rate. RED should only be configured on an interface where most of the traffic is TCP/IP traffic.
Cisco recommends using the default value for the exponential weighting constant; however, you may need to change this value depending on your operational environment. For example, a value of 10 (the default), which might achieve a loss rate of 10-4, is recommended for high-speed links such as DS3 and OC3, whereas a value of 7, which might achieve a loss rate of 10-3, is recommended for T1 links.
Random early detection cannot be configured on an interface already configured with custom, priority, or fair queueing.
When RSVP is configured on the interface, packets from other traffic flows are dropped before RSVP flows (when possible). Also, the IP precedence of the packet determines whether the packet is dropped. Lower-precedence traffic is dropped before higher-precedence traffic. Therefore, lower-precedence traffic is more likely to be throttled back.
Example
The following example shows how to enable random early detection on a serial interface:
interface serial 0random-detectRelated Commands
A dagger (†) indicates that the command is documented outside this chapter.
custom-queue-list
fair-queue
ip rsvp bandwidth †
priority-group
priority-list default
queue-list default
random-detect
show interface †request-data-size
To set the protocol data size in the payload of the response time reporter probe's request packet, use the request-data-size response time reporter configuration command. Use the no form of this command to return to the default value.
request-data-size byte
no request-data-sizeSyntax Description
byte
Size of the protocol data in the payload of the probe's request packet. Range is 0 to the protocol's maximum. The default is 1 byte.
Default
1 byte
Command Mode
Response time reporter configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
When the protocol name has the suffix "appl," the packet uses both a request and respond data size (see the response-data-size response time reporter configuration command), and the data size is 12 bytes smaller than the normal payload size (this 12 bytes is the ARR Header used to control send and data response sizes).
Example
In the following example, probe 3's request packet size is set to 40 bytes:
rtr 3type echo protocol snalu0echoappl cwbc0arequest-data-size 40Related Commands
response-data-size
To set the protocol data size in the payload of the response time reporter probe's response packet, use the response-data-size response time reporter configuration command. Use the no form of this command to return to the default value.
response-data-size byte
no response-data-sizeSyntax Description
byte
Size of the protocol data in the payload in the probe's response packet. For "appl" protocols, the default is 0 bytes. For all others, the default is the same value as the request-data-size.
Default
For "appl" protocols, 0 bytes
For all others, the same value as the request-data-size
Command Mode
Response time reporter configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
The response-data-size command is only applicable for protocols defined with the type command that end in "appl" (for example, snalu0echoappl). When the protocol ends in "appl," the response data size is 12 bytes smaller than normal payload size.
Example
In the following example, probe 3's response packet size is set to 1440 bytes:
rtr 3type echo protocol snalu0echoappl cwbc0aresponse-data-size 1440Related Commands
rmon
To enable Remote Network Monitoring (RMON) on an Ethernet interface, use the rmon interface configuration command. Use the no form of this command to disable RMON on the interface.
rmon {native | promiscuous}
no rmonSyntax Description
Default
RMON is disabled on the interface.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
This command enables RMON on Ethernet interfaces of Cisco 2500 series routers only. A generic RMON console application is required in order to use the RMON network management capabilities. SNMP must also be configured. RMON provides visibility of individual nodal activity and allows you to monitor all nodes and their interaction on a LAN segment. When the rmon command is issued, the router automatically installs an Ethernet statistics study for the associated interface.
Note
All Cisco IOS software Release 11.1 feature sets support RMON alarm and event groups. Additional RMON groups are supported in certain feature sets. Refer to the Cisco IOS Release 11.1 Release Notes for feature set descriptions. As a security precaution, support for the packet capture group allows capture of packet header information only; data payloads are not captured.
The RMON MIB is described in RFC 1757.
Example
The following example enables RMON on Ethernet interface 0 and allows the router to examine only packets destined for the interface:
interface ethernet 0rmon nativeRelated Commands
rmon alarm
rmon event
rmon queuesize
show rmonrmon alarm
To set an alarm on any MIB object, use the rmon alarm configuration command. Use the no form of this command to disable the alarm.
rmon alarm number variable interval {delta | absolute} rising-threshold value [event-number]
falling-threshold value [event-number] [owner string]
no rmon alarm numberSyntax Description
Default
No alarms configured
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
The MIB object must be specified as a dotted decimal value after the entry sequence (for example, ifEntry.10.1). You cannot specify the variable name and the instance (for example, ifInOctets.1) or the entire dotted decimal notation. The variable must be of the form entry.integer.instance.
To disable the RMON alarms, you must use the no form of the command on each configured alarm. For example, enter no rmon alarm 1, where the 1 identifies which alarm is to be removed.
See RFC 1757 for more information about the RMON alarm group.
Example
The following example configures an RMON alarm using the rmon alarm command:
rmon alarm 10 ifEntry.20.1 20 delta rising-threshold 15 1 falling-threshold 0owner jjohnsonThis example configures RMON alarm number 10. The alarm monitors the MIB variable ifEntry.20.1 once every 20 seconds until the alarm is disabled, and checks the change in the variable's rise or fall. If the ifEntry.20.1 value shows a MIB counter increase of 15 or more, such as from 100000 to 100015, the alarm is triggered. The alarm in turn triggers event number 1, which is configured with the rmon event command. Possible events include a log entry or a SNMP trap. If the ifEntry.20.1 value changes by 0 (falling-threshold 0), the alarm is reset and can be triggered again.
Related Commands
rmon event
To add or remove an event in the RMON event table that is associated with an RMON event number, use the rmon event global configuration command. Use the no form of this command to disable RMON on the interface.
rmon event number [log] [trap community] [description string] [owner string]
no rmon event numberSyntax Description
Default
No events configured
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
This command applies only to the AS5200 access server.
See RFC 1757 for more information about the RMON MIB.
Example
The following example enables the rmon event command:
rmon event 1 log trap eventtrap description "High ifOutErrors" owner sdurhamThis example configuration creates RMON event number 1, which is defined as High ifOutErrors, and generates a log entry when the event is triggered by an alarm. The user sdurham owns the row that is created in the event table by this command. This configuration also generates a Simple Network Management Protocol (SNMP) trap when the event is triggered.
Related Commands
rmon queuesize
To change the size of the queue that holds packets for analysis by the Remote Network Monitoring (RMON) process, use the rmon queuesize global configuration command. Use the no form of this command to restore the default value.
rmon queuesize size
no rmon queuesizeSyntax Description
size
Number of packets allowed in the queue awaiting RMON analysis. Default queue size is 64 packets.
Default
64 packets
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
This command applies to the RMON function, which is available on Ethernet interfaces of Cisco 2500 series routers only.
You might want to increase the queue size if the RMON function indicates it is dropping packets. You can determine this from the output of the show rmon command or from the etherStatsDropEvents object in the etherStats table. A feasible maximum queue size depends on the amount of memory available in the router and the configuration of the buffer pool.
Example
The following example configures the RMON queue size to be 128 packets:
rmon queuesize 128Related Commands
rtr
To configure a response time reporter probe, use the rtr global configuration command. Use the no form of this command to remove all configuration information for a probe including the probe's schedule, reaction configuration, and reaction triggers.
rtr probe
no rtr probeSyntax Description
Default
None
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
A probe is used for the purpose of collecting response time information.
Each platform has a limit on the number of probes that can be configured. In general this limit is less than 20.
Debugging is supported only on the first 32 probe numbers.
The response time reporter feature allows customers to monitor the performance of their network, network resources, and applications by measuring response times and availability. With this feature, a customer can perform troubleshooting, problem notification, and preproblem analysis. The response time reporter feature is currently available only with the IBM feature set of the Cisco IOS software. For more information, refer to the "Managing the System" chapter in the Configuration Fundamentals Configuration Guide and the Cisco Round-Trip Time Monitor (RTTMON) MIB in the Cisco MIB User Quick Reference.
This command places you in (config-rtr) mode.
Note
Use the following response time reporter configuration commands (config-rtr) to configure the probe's characteristics:
•
•
•
•
After you configure a probe, you must schedule the probe. For information on scheduling a probe, refer to the rtr schedule global configuration command. You can also optionally set reaction triggers for the probe. For information on reaction triggers, refer to the rtr reaction-configuration and rtr reaction-trigger global configuration commands.
To display the probe's current configuration settings, use the show rtr configuration EXEC command.
Example
In the following example, probe 1 is configured to perform end-to-end response time operations using an SNA LU Type 0 connection with the host name cwbc0a. Only the type response time reporter configuration command is required; all others are optional.
rtr 1type echo protocol snalu0echoappl cwbc0arequest-data-size 40response-data-size 1440
Note
Related Commands
rtr reaction-configuration
rtr reaction-trigger
rtr reset
rtr schedulertr reaction-configuration
To configure certain actions to occur based on events under the control of the response time reporter, use the rtr reaction-configuration global configuration command. Use the no form of this command to return to the probe's default values.
rtr reaction-configuration probe [connection-loss-enable] [timeout-enable]
[threshold-falling milliseconds] [threshold-type option] [action-type option]
no rtr reaction-configuration probeSyntax Description
Default
No reactions are generated.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Triggers are used for diagnostics purposes and are not used in normal operation.
You can use triggers to assist you in determining where delays are happening in the network when excessive delays are being seen on an end-to-end basis.
The reaction applies only to attempts to the target (that is, attempts to any hops along the path in pathEcho do not generate reactions).
Note
Example
In the following example, probe 19 sends an SNMP trap when there is an over or falling threshold violation:
rtr reaction-configuration 19 threshold-type immediate action-type trapOnlyshows that an alert (rising trap) would be issued immediately when the response time exceeds the rising threshold and a resolution (falling trap) would be issued immediately when the response time drops below the falling threshold.
Figure 2 Example of Rising and Falling Thresholds
Related Commands
rtr
rtr reaction-trigger
threshold
timeoutrtr reaction-trigger
To define a second response time reporter probe to make the transition from a "pending" state to an "active" state when one of the trigger action-type options are defined with the rtr reaction-configuration global configuration command, use the rtr reaction-trigger global configuration command. Use the no form of this command to remove the trigger combination.
rtr reaction-trigger probe target-probe
no rtr reaction-trigger probeSyntax Description
Default
None
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Triggers are usually used for diagnostics purposes and are not used in normal operation.
Example
In the following example, probe 1's state is changed from pending state to active state when probe 2's action-type occurs:
rtr reaction-trigger 2 1Related Commands
rtr
rtr reaction-configuration
rtr schedulertr reset
To perform a shutdown and restart of the response time reporter, use the rtr reset global configuration command.
rtr reset
Syntax Description
This command has no arguments or keywords.
Default
None
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
CautionUse the rtr reset command only in extreme situations such as the incorrect configuration of a number of probes.
The rtr reset command stops all probes, clears response time reporter configuration information, and returns the response time reporter feature to the startup condition. This command does not reread the response time reporter configuration stored in startup-config in NVRAM. You must retype the configuration or perform a config memory command.
Example
The following example illustrates how to reset the response time reporter feature:
rtr resetrtr schedule
To configure the time parameters for a response time reporter probe, use the rtr schedule global configuration command. Use the no form of this command to stop the probe and restart it with the default parameters (that is, pending).
rtr schedule probe [life seconds] [start-time {pending | now | hh:mm [month day |
day month]}] [ageout seconds]
no rtr schedule probeSyntax Description
Default
Place the probe in a pending state (that is, the probe is started but not actively collecting information).
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
After you schedule the probe with the rtr schedule command, you cannot change the probe's configuration (with the rtr global configuration command). To change the probe's configuration, use the no form of the rtr global command and reenter the configuration information.
If the probe is in a pending state, you can define the conditions under which the probe makes the transition from pending to active with the rtr reaction-trigger and rtr reaction-configuration global configuration commands. When the probe is in an active state, it immediately begins collecting information.
The following time line shows the probe's age-out process:
W----------------------X----------------------Y----------------------Zwhere:
•
•
•
•
Age out starts counting down at W and Y, is suspended between X and Y, and is reset to its configured size at Y.
It is possible for the probe to age out before it executes (that is, Z can occur before X). To ensure that this does not happen, the difference between the probe's configuration time and start time (X and W) must be less than the age-out seconds.
Note
Example
In the following example, probe 25 begins actively collecting data at 3:00 p.m. on April 5. This probe will age out after 12 hours of inactivity, which can be before it starts or after it has finished with its life. When this probe ages out, all configuration information for the probe is removed (that is, the configuration information is no longer in the running-config in RAM.
rtr schedule 25 life 43200 start-time 15:00 apr 5 ageout 43200Related Commands
rtr
rtr reaction-configuration
rtr reaction-triggersamples-of-history-kept
To set the number of entries kept in the history table per bucket for the response time reporter probe, use the samples-of-history-kept response time reporter configuration command. Use the no form of this command to return to the default value.
samples-of-history-kept samples
no samples-of-history-keptSyntax Description
samples
Number of entries kept in the history table per bucket. The default is 16 entries for type pathEcho and 1 entry for type echo.
Default
16 entries for type pathEcho
1 entry for type echo
Command Mode
Response time reporter configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Use the samples-of-history-kept command to control how many entries are saved in the history table. To control the type of information that gets saved in the history table, use the filter-for-history command. To set how many buckets get created in the history table, use the buckets-of-history-kept command.
A probe can collect history and capture statistics. 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 response time reporter configuration command to collect history.
Note
Example
In the following example, ten entries are kept in the history table for each of the of probe's three lives:
rtr 1type pathecho protocol ipIcmpEcho 172.16.1.176lives-of-history-kept 3samples-of-history-kept 10Related Commands
buckets-of-history-kept
filter-for-history
lives-of-history-kept
rtrscheduler allocate
To guarantee CPU time for processes, use the scheduler allocate global configuration command on the Cisco 7200 series and Cisco 7500 series. The no form of this command restores the default.
scheduler allocate interrupt-time process-time
no scheduler allocateSyntax Description
Default
Approximately 5 percent of the CPU is available for process tasks.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
This command applies to the Cisco 7200 series and Cisco 7500 series.
CautionCisco recommends that you do not change the default values.
Example
The following example makes 20 percent of the CPU available for process tasks:
scheduler allocate 2000 500Related Command
scheduler interval
To control the maximum amount of time that can elapse without running system processes, use the scheduler interval global configuration command. The no form of this command restores the default.
scheduler interval milliseconds
no scheduler intervalSyntax Description
milliseconds
Integer that specifies the interval, in milliseconds. The minimum interval that you can specify is 500 milliseconds; there is no maximum value.
Default
High-priority operations are allowed to use as much of the central processor as needed.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The normal operation of the network server allows the switching operations to use as much of the central processor as is required. If the network is running unusually heavy loads that do not allow the processor the time to handle the routing protocols, give priority to the system process scheduler. High-priority operations are allowed to use as much of the central processor as needed.
On the Cisco 7200 series and Cisco 7500 series, use the scheduler allocate global configuration command.
Example
The following example changes the low-priority process schedule to an interval of 750 milliseconds:
scheduler interval 750Related Command
service decimal-tty
To specify that line numbers be displayed and interpreted as decimal numbers rather than octal numbers, use the service decimal-tty global configuration command. Use the no form of this command to restore the default.
service decimal-tty
no service decimal-ttySyntax Description
This command has no arguments or keywords.
Default
Decimal numbers on the 500-CS and Cisco 2500 Series.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
The following example shows how to display decimal rather than octal line numbers:
service decimal-ttyservice exec-wait
To delay the startup of the EXEC on noisy lines, use the service exec-wait global configuration command. Use the no form of this command to disable this feature.
service exec-wait
no service exec-waitSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command delays startup of the EXEC until the line has been idle (no traffic seen) for 3 seconds. The default is to enable the line immediately on modem activation.
This command is useful on noisy modem lines or when a modem attached to the line is configured to ignore MNP or V.42 negotiations, and MNP or V.42 modems may be dialing in. In these cases, noise or MNP/V.42 packets may be interpreted as usernames and passwords, causing authentication failure before the user gets a chance to type a username/password. The command is not useful on non-modem lines or lines without some kind of login configured.
Example
The following example delays the startup of the EXEC:
service exec-waitservice finger
To allow Finger protocol requests (defined in RFC 742) to be made of the network server, use the service finger global configuration command. This service is equivalent to issuing a remote show users command. Use the no form of this command to remove this service.
service finger
no service fingerSyntax Description
This command has no arguments or keywords.
Default
Enabled
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
The following is an example of how to disable the Finger protocol:
no service fingerservice hide-telnet-address
To hide addresses while trying to establish a Telnet session, use the service hide-telnet-address global configuration command. Use the no form of this command to remove this service.
service hide-telnet-address
no service hide-telnet-addressSyntax Description
This command has no arguments or keywords.
Default
Addresses are displayed.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
When you attempt to connect to a device, the router displays addresses and other messages (for example, Trying router1 (171.69.1.154, 2008)...). With the hide feature, the router suppresses the display of the address (for example, Trying router1 address #1...). The router continues to display all other messages that would normally display during a connection attempt, such as detailed error messages if the connection was not successful.
The hide feature improves the functionality of the busy-message feature. When you configure only the busy-message command, the normal messages generated during a connection attempt are not displayed; only the busy-message is displayed. When you use the hide and busy features together you can customize the information displayed during Telnet connection attempts. When you configure the service hide-telnet-address command and the busy-message command, the router suppresses the address and displays the message specified with the busy-message command if the connection attempt is not successful.
Example
The following example shows how to hide Telnet addresses:
service hide-telnet-addressRelated Command
A dagger (†) indicates that the command is documented outside this chapter.
busy-message †
service nagle
To enable the Nagle congestion control algorithm, use the service nagle global configuration command. Use the no form of this command to disable this feature.
service nagle
no service nagleSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
When using a standard TCP implementation to send keystrokes between machines, TCP tends to send one packet for each keystroke typed. On larger networks, many small packets use up bandwidth and contribute to congestion.
John Nagle's algorithm (RFC 896) helps alleviate the small-packet problem in TCP. In general, it works this way: The first character typed after connection establishment is sent in a single packet, but TCP holds any additional characters typed until the receiver acknowledges the previous packet. Then the second, larger packet is sent, and additional typed characters are saved until the acknowledgment comes back. The effect is to accumulate characters into larger chunks, and pace them out to the network at a rate matching the round-trip time of the given connection. This method is usually a good for all TCP-based traffic. However, do not use the service nagle command if you have XRemote users on X Window sessions.
Example
The following example enables the Nagle algorithm:
service nagleservice prompt config
To display the configuration prompt (config), use the service prompt config global configuration command. Use the no form of this command to remove the configuration prompt.
service prompt config
no service prompt configSyntax Description
This command has no arguments or keywords.
Default
Router(config)#
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
Examples
In the following example, notice how the configuration prompt varies, depending on what subdivision of configuration mode you are using:
Router#config terminalEnter configuration commands, one per line. End with CNTL/Z.Router(config)#interface ethernet 0Router(config-if)#line config 0Router(config-line)#router ripRouter(config-router)#map-list murugaRouter(config-map-list)#map-class atm barRouter(config-map-class)#exitRouter(config)#exitRouter#Related Commands
service slave-log
To allow slave Versatile Interface Processor (VIP) cards to log important error messages to the console, use the service slave-log global configuration command. Use the no form of this command to disable slave logging.
service slave-log
no service slave-logSyntax Description
This command has no arguments or keywords.
Default
This command is enabled by default.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
This command allows slave slots to log error messages of level 2 or higher (critical, alerts, and emergencies).
Examples
The following example logs important messages from the slave cards to the console:
service slave-logThe following example illustrates sample output when this command is enabled:
%IPC-5-SLAVELOG: VIP-SLOT2:IPC-2-NOMEM: No memory available for IPC system initializationThe first line indicates which slot sent the message. The second line contains the error message.
service tcp-keepalives-in
To generate keepalive packets on idle incoming network connections (initiated by the remote host), use the service tcp-keepalives-in global configuration command. The no form of this command with the appropriate keyword disables the keepalives.
service tcp-keepalives-in
no service tcp-keepalives-inSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
The following example generates keepalives on incoming TCP connections:
service tcp-keepalives-inservice tcp-keepalives-out
To generate keepalive packets on idle outgoing network connections (initiated by a user), use the service tcp-keepalives-out global configuration command. The no form of this command with the appropriate keyword disables the keepalives.
service tcp-keepalives-out
no service tcp-keepalives-outSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
The following example generates keepalives on outgoing TCP connections:
service tcp-keepalives-outservice tcp-small-servers
To access minor TCP/IP services available from hosts on the network, use the service tcp-small-servers command. Use the no form of the command to disable these services.
service tcp-small-servers
no service tcp-small-serversSyntax Description
This command has no arguments or keywords.
Default
Enabled
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
By default, the TCP servers for Echo, Discard, Chargen, and Daytime services are enabled.
When you disable the minor TCP/IP servers, access to the Echo, Discard, Chargen, and Daytime ports cause the Cisco IOS software to send a TCP RESET packet to the sender and discard the original incoming packet.
Note
Example
The following example enables minor TCP/IP services available from the network:
service tcp-small-serversservice telnet-zero-idle
To set the TCP window to zero (0) when the Telnet connection is idle, use the service telnet-zero-idle global configuration command. Use the no form of this command to disable this feature.
service telnet-zero-idle
no service telnet-zero-idleSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Normally, data sent to noncurrent Telnet connections is accepted and discarded. When service telnet-zero-idle is enabled, if a session is suspended (that is, some other connection is made active or the EXEC is sitting in command mode), the TCP window is set to zero. This action prevents the remote host from sending any more data until the connection is resumed. Use this command when it is important that all messages sent by the host be seen by the users and the users are likely to use multiple sessions.
Do not use this command if your host will eventually time out and log out a TCP user whose window is zero.
Example
The following example sets the TCP window to zero when the Telnet connection is idle:
service telnet-zero-idleRelated Command
A dagger (†) indicates that the command is documented outside this chapter.
resume †
service timestamps
To configure the system to timestamp debugging or logging messages, use one of the service timestamps global configuration commands. Use the no form of this command to disable this service.
service timestamps type [uptime]
service timestamps type datetime [msec] [localtime] [show-timezone]
no service timestamps typeSyntax Description
Default
No timestamping.
If service timestamps is specified with no arguments or keywords, default is service timestamps debug uptime.
The default for service timestamps type datetime is to format the time in UTC, with no milliseconds and no time zone name.
The command no service timestamps by itself disables timestamps for both debug and log messages.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Timestamps can be added to either debugging or logging messages independently. The uptime form of the command adds timestamps in the format HHHH:MM:SS, indicating the time since the system was rebooted. The datetime form of the command adds timestamps in the format MMM DD HH:MM:SS, indicating the date and time according to the system clock. If the system clock has not been set, the date and time are preceded by an asterisk (*) to indicate that the date and time are probably not correct.
Examples
The following example enables timestamps on debugging messages, showing the time since reboot:
service timestamps debug uptimeThe following example enables timestamps on logging messages, showing the current time and date relative to the local time zone, with the time zone name included:
service timestamps log datetime localtime show-timezoneRelated Commands
A dagger (†) indicates that the command is documented in the Debug Command Reference.
clock set
debug †
ntpservice udp-small-servers
To access minor User Datagram Protocol (UDP) services available from hosts on the network, use the service udp-small-servers command. Use the no form of the command to disable these services.
service udp-small-servers
no service udp-small-serversSyntax Description
This command has no arguments or keywords.
Default
Enabled
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
By default the UPD servers for Echo, Discard, and Chargen services are enabled.
When you disable the servers, access to Echo, Discard, and Chargen ports causes the Cisco IOS software to send an "ICMP port unreachable" message to the sender and discard the original incoming packet.
Note
Example
The following example disables minor UDP services on the router:
no service udp-small-serversshow aliases
To display all alias commands, or the alias commands in a specified mode, use the show aliases EXEC command.
show aliases [mode]
Syntax Description
mode
(Optional) Command mode. See in the description of the alias command for acceptable options for the mode argument.
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
All of the modes listed in have their own prompts, except for the null interface mode. For example, the prompt for interface configuration mode is Router(config-if).
Sample Display
The following is sample output from the show aliases exec commands. The aliases configured for commands in EXEC mode are displayed.
Router# show aliases execExec mode aliases:h helplo logoutp pingr resumes showw whereRelated Command
show buffers
Use the show buffers EXEC command to display statistics for the buffer pools on the network server.
show buffers [type number | alloc [dump]]
Syntax Description
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Sample Displays
The following is sample output from the show buffers command with no arguments, showing all buffer pool information:
Router# show buffersBuffer elements:398 in free list (500 max allowed)1266 hits, 0 misses, 0 createdPublic buffer pools:Small buffers, 104 bytes (total 50, permanent 50):50 in free list (20 min, 150 max allowed)551 hits, 0 misses, 0 trims, 0 createdMiddle buffers, 600 bytes (total 25, permanent 25):25 in free list (10 min, 150 max allowed)39 hits, 0 misses, 0 trims, 0 createdBig buffers, 1524 bytes (total 50, permanent 50):49 in free list (5 min, 150 max allowed)27 hits, 0 misses, 0 trims, 0 createdVeryBig buffers, 4520 bytes (total 10, permanent 10):10 in free list (0 min, 100 max allowed)0 hits, 0 misses, 0 trims, 0 createdLarge buffers, 5024 bytes (total 0, permanent 0):0 in free list (0 min, 10 max allowed)0 hits, 0 misses, 0 trims, 0 createdHuge buffers, 18024 bytes (total 0, permanent 0):0 in free list (0 min, 4 max allowed)0 hits, 0 misses, 0 trims, 0 createdInterface buffer pools:Ethernet0 buffers, 1524 bytes (total 64, permanent 64):16 in free list (0 min, 64 max allowed)48 hits, 0 fallbacks16 max cache size, 16 in cacheEthernet1 buffers, 1524 bytes (total 64, permanent 64):16 in free list (0 min, 64 max allowed)48 hits, 0 fallbacks16 max cache size, 16 in cacheSerial0 buffers, 1524 bytes (total 64, permanent 64):16 in free list (0 min, 64 max allowed)48 hits, 0 fallbacks16 max cache size, 16 in cacheSerial1 buffers, 1524 bytes (total 64, permanent 64):16 in free list (0 min, 64 max allowed)48 hits, 0 fallbacks16 max cache size, 16 in cacheTokenRing0 buffers, 4516 bytes (total 48, permanent 48):0 in free list (0 min, 48 max allowed)48 hits, 0 fallbacks16 max cache size, 16 in cacheTokenRing1 buffers, 4516 bytes (total 32, permanent 32):32 in free list (0 min, 48 max allowed)16 hits, 0 fallbacks0 failures (0 no memory)describes significant fields shown in the display.
