Cisco ASR 9000 Series Aggregation Services Router IP Addresses and Services Command Reference, Release 4.1
Host Services and Applications Commands
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Host Services and Applications Commands

Host Services and Applications Commands

This chapter describes the commands used to configure and monitor host services and applications, such as Domain Name System (DNS), Telnet, File Transfer Protocol (FTP), and Trivial File Transfer Protocol (TFTP), and Remote Copy Protocol (RCP).

For detailed information about host services and applications concepts, configuration tasks, and examples, refer to the Cisco ASR 9000 Series Aggregation Services Router IP Addresses and Services Configuration Guide.

cinetd rate-limit

To configure the rate limit at which service requests are accepted by Cisco inetd (Cinetd), use the cinetd rate-limit command in global configuration mode. To restore the default, use the no form of this command.

cinetd rate-limit value

no cinetd rate-limit value

Syntax Description

value

Number of service requests that are accepted per second. Range is 1 to 100. Default is 1.

Command Default

One service request per second is accepted.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

Any service request that exceeds the rate limit is rejected. The rate limit is applied to individual applications.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows the cinetd rate-limit being set to 10:


RP/0/RSP0/CPU0:router# config
RP/0/RSP0/CPU0:router(config)# cinetd rate-limit 10

clear host

To delete temporary entries from the hostname-to-address cache, use the clear host command in EXEC mode.

clear host { host-name | * }

Syntax Description

host-name

Name of host to be deleted.

*

Specifies that all entries in the local cache be deleted.

Command Default

No default behavior or values

Command Modes

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

The dynamic host entries in the cache are cleared.

The temporary entries in the cache are cleared; the permanent entries that were entered with the domain ipv4 host or the domain ipv6 host command are not cleared.

By default, no static mapping is configured.

Task ID

Task ID

Operations

ip-services

execute

Examples

The following example shows how to clear all temporary entries from the hostname-and-address cache:


RP/0/RSP0/CPU0:router# clear host *

Related Commands

Command

Description

domain ipv4 host

Defines a static IPv4 hostname-to-address mapping in the host cache.

domain ipv6 host

Defines a static IPv6 hostname-to-address mapping in the host cache.

show hosts

Displays the default domain name, the style of name lookup service, a list of name server hosts, and the cached list of hostnames and addresses.

domain ipv4 host

To define a static hostname-to-address mapping in the host cache using IPv4, use the domain ipv4 host command in global configuration mode. To remove the domain ipv4 host command from the configuration file and restore the system to its default condition, use the no form of this command.

domain ipv4 host host-name v4address2......v4address8

no domain ipv4 host host-name v4address1

Syntax Description

host-name

Name of the host. The first character can be either a letter or a number.

v4address1

Associated IP address.

v4address2...v4address8

(Optional) Additional associated IP address. You can bind up to eight addresses to a hostname.

Command Default

No static mapping is configured.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

The first character can be either a letter or a number. If you use a number, the operations you can perform (such as ping) are limited.

Task ID

Task ID

Operations

ip-services

read, write

basic-services

read, write

Examples

The following example shows how to define two IPv4 static mappings:


RP/0/RSP0/CPU0:router(config)# domain ipv4 host host1 192.168.7.18
RP/0/RSP0/CPU0:router(config)# domain ipv4 host bost2 10.2.0.2 192.168.7.33

domain ipv6 host

To define a static hostname-to-address mapping in the host cache using IPv6, use the domain ipv6 host command in global configuration mode. To remove the domain ipv6 host command from the configuration file and restore the system to its default condition, use the no form of this command.

domain ipv6 host host-name v6address1 [v6address2 ......v6address4]

no domain ipv6 host host-name v6address1

Syntax Description

host-name

Name of the host. The first character can be either a letter or a number.

v6address1

Associated IP address.

v6address2...v6address4

(Optional) Additional associated IP address. You can bind up to four addresses to a hostname.

Command Default

No static mapping is configured. IPv6 address prefixes are not enabled.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

The first character can be either a letter or a number. If you use a number, the operations you can perform (such as ping) are limited.

Task ID

Task ID

Operations

ip services

read, write

Examples

The following example shows how to define two IPv6 static mappings:


RP/0/RSP0/CPU0:router(config)# domain ipv6 host host1 ff02::2
RP/0/RSP0/CPU0:router(config)# domain ipv6 host host2 ff02::1

domain list

To define a list of default domain names to complete unqualified hostnames, use the domain list command in global configuration mode. To delete a name from a list, use the no form of this command.

domain list domain-name

no domain list domain-name

Syntax Description

domain-name

Domain name. Do not include the initial period that separates an unqualified name from the domain name.

Command Default

No domain names are defined.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

If there is no domain list, the domain name that you specified with the domain name (IPAddr) command is used to complete unqualified hostnames. If there is a domain list, the default domain name is not used. The domain list command is similar to the domain name (IPAddr) command, except that you can use the domain list command to define a list of domains, each to be tried in turn.

Task ID

Task ID

Operations

ip-service

read, write

Examples

The following example shows how to add several domain names to a list:


RP/0/RSP0/CPU0:router(config)# domain list domain1.com
RP/0/RSP0/CPU0:router(config)# domain list domain2.edu

The following example shows how to add a name to and then delete a name from the list:


RP/0/RSP0/CPU0:router(config)# domain list domain3.edu
RP/0/RSP0/CPU0:router(config)# no domain list domain2.edu

Related Commands

Command

Description

domain name (IPAddr)

Defines a default domain name to complete unqualified hostnames (names without a dotted-decimal domain name).

show hosts

Displays the default domain name, the style of name lookup service, a list of name server hosts, and the cached list of hostnames and addresses.

domain lookup disable

To disable the IP Domain Name System (DNS)-based hostname-to-address translation, use the domain lookup disable command in global configuration mode. To remove the specified command from the configuration file and restore the system to its default condition, use the no form of this command.

domain lookup disable

no domain lookup disable

Syntax Description

This command has no keywords or arguments.

Command Default

The IP DNS-based host-to-address translation is enabled.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

Using the no command removes the specified command from the configuration file and restores the system to its default condition. The no form of this command is not stored in the configuration file.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to enable the IP DNS-based hostname-to-address translation:


RP/0/RSP0/CPU0:router(config)# domain lookup disable

Related Commands

Command

Description

domain name (IPAddr)

Defines a default domain name to complete unqualified hostnames (names without a dotted-decimal domain name).

domain name-server

Specifies the address of one or more name servers to use for name and address resolution.

show hosts

Displays the default domain name, the style of name lookup service, a list of name server hosts, and the cached list of hostnames and addresses.

domain name (IPAddr)

To define a default domain name that the software uses to complete unqualified hostnames, use the domain name command in the appropriate mode. To remove the name, use the no form of this command.

domain name domain-name

no domain name domain-name

Syntax Description

domain-name

Default domain name used to complete unqualified hostnames. Do not include the initial period that separates an unqualified name from the domain name.

Command Default

There is no default domain name.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

If a hostname does not contain a domain name, then a dot and the domain name configured by the domain name command are appended to the hostname before it is added to the host table.

If no domain name is configured by the domain name command and the user provides only the hostname, then the request is not looked up.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to define cisco.com as the default domain name:


RP/0/RSP0/CPU0:router# config
RP/0/RSP0/CPU0:router(config)# dhcp ipv4
RP/0/RSP0/CPU0:router(config-dhcpv4)# profile TEST server
RP/0/RSP0/CPU0:router(config-dhcpv4-server-profile)# broadcast-flag policy unicast-always


Related Commands

Command

Description

domain list

Defines a list of default domain names to complete unqualified hostnames.

domain name-server

Specifies the address of one or more name servers to use for name and address resolution.

show hosts

Displays the default domain name, the style of name lookup service, a list of name server hosts, and the cached list of hostnames and addresses.

domain name-server

To specify the address of one or more name servers to use for name and address resolution, use the domain name-server command in global configuration mode. To remove the address specified, use the no form of this command.

domain name-server server-address

no domain name-server server-address

Syntax Description

server-address

IP address of a name server.

Command Default

If no name server address is specified, the default name server is 255.255.255.255. IPv4 and IPv6 address prefixes are not enabled.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

You can enter up to six addresses, but only one for each command.

If no name server address is specified, the default name server is 255.255.255.255 so that the DNS lookup can be broadcast to the local network segment. If a DNS server is in the local network, it replies. If not, there might be a server that knows how to forward the DNS request to the correct DNS server.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to specify host 192.168.1.111 as the primary name server and host 192.168.1.2 as the secondary server:


RP/0/RSP0/CPU0:router(config)# domain name-server 192.168.1.111
RP/0/RSP0/CPU0:router(config)# domain name-server 192.168.1.2

Related Commands

Command

Description

domain lookup disable

Disables the domain lookup.

domain name (IPAddr)

Defines a default domain name to complete unqualified hostnames (names without a dotted-decimal domain name).

ftp client anonymous-password

To assign a password for anonymous users, use the ftp client anonymous-password command in global configuration mode. To remove the ftp client anonymous-password command from the configuration file and restore the system to its default condition, use the no form of this command.

ftp client anonymous-password password

no ftp client anonymous-password

Syntax Description

password

Password for the anonymous user.

Command Default

No default behavior or values

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The ftp client anonymous-password command is File Transfer Protocol (FTP) server dependent.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to set the anonymous password to xxxx:


RP/0/RSP0/CPU0:router(config)# ftp client anonymous-password xxxx

Related Commands

Command

Description

ftp client passive

Configures the software to use only passive File Transfer Protocol (FTP) connections.

ftp client password

Specifies the password for the File Transfer Protocol (FTP) connections.

ftp client source-interface

Specifies the source IP address for File Transfer Protocol (FTP) connections.

ftp client username

Specifies the username for File Transfer Protocol (FTP) connections.

ftp client passive

To configure the software to use only passive File Transfer Protocol (FTP) connections, use the ftp client passive command in global configuration mode. To remove the ftp client passive command from the configuration file and restore the system to its default condition, use the no form of this command.

ftp client passive

no ftp client passive

Syntax Description

This command has no keywords or arguments.

Command Default

FTP data connections are active.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Using the ftp client passive command allows you to make only passive-mode FTP connections. To specify the source IP address for FTP connections, use the ftp client source-interface command.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to configure the networking device to use only passive FTP connections:


RP/0/RSP0/CPU0:router(config)# ftp client passive

1d:3h:54:47: ftp_fs[16437]: FTP: verifying tuple passive (SET).
1d:3h:54:47: ftp_fs[16437]: FTP: applying tuple passive (SET).
1d:3h:54:47: ftp_fs[16437]: FTP: passive mode has been enabled.

Related Commands

Command

Description

ftp client anonymous-password

Assigns a password for anonymous users.

ftp client password

Specifies the password for the File Transfer Protocol (FTP) connections.

ftp client source-interface

Specifies the source IP address for File Transfer Protocol (FTP) connections.

ftp client username

Specifies the username for File Transfer Protocol (FTP) connections.

ftp client password

To specify the password for the File Transfer Protocol (FTP) connections, use the ftp client password command in global configuration mode. To disable this feature, use the no form of this command.

ftp client password { clear-text-password | clear clear-text password | encrypted encrypted-text password }

no ftp client password { clear-text-password | clear clear-text password | encrypted encrypted-text password }

Syntax Description

clear-text-password

Specifies an unencrypted (cleartext) user password

clear clear-text password

Specifies an unencrypted (cleartext) shared password.

encrypted encrypted-text password

Specifies an encrypted shared password.

Command Default

No default behavior or values

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to specify the password for the File Transfer Protocol (FTP) connections:


RP/0/RSP0/CPU0:router(config)# ftp client password lab

Related Commands

Command

Description

ftp client anonymous-password

Assigns a password for anonymous users.

ftp client passive

Configures the software to use only passive File Transfer Protocol (FTP) connections.

ftp client source-interface

Specifies the source IP address for File Transfer Protocol (FTP) connections.

ftp client username

Specifies the username for File Transfer Protocol (FTP) connections.

ftp client source-interface

To specify the source IP address for File Transfer Protocol (FTP) connections, use the ftp client source-interface command in global configuration mode. To remove the ftp client source-interface command from the configuration file and restore the system to its default condition, use the no form of this command.

ftp client source-interface type interface-path-id

no ftp client source-interface type interface-path-id

Syntax Description

type

Interface type. For more information, use the question mark (?) online help function.

interface-path-id

Physical interface or virtual interface.

Note   

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark (?) online help function.

Command Default

The FTP source address is the IP address of the interface used by the FTP packets to leave the networking device.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use this command to set the same source address for all FTP connections. To configure the software to use only passive FTP connections, use the ftp client passive command.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to configure the IP address associated with GigabitEthernet interface 0/1/2/1 as the source address on all FTP packets, regardless of which interface is actually used to send the packet:


RP/0/RSP0/CPU0:router(config)# ftp client source-interface gigabitethernet 0/1/2/1

Related Commands

Command

Description

ftp client anonymous-password

Assigns a password for anonymous users.

ftp client passive

Configures the software to use only passive File Transfer Protocol (FTP) connections.

ftp client password

Specifies the password for the File Transfer Protocol (FTP) connections.

ftp client username

Specifies the username for File Transfer Protocol (FTP) connections.

ftp client username

To specify the username for File Transfer Protocol (FTP) connections, use the ftp client username command in global configuration mode. To disable this feature, use the no form of this command.

ftp client username username

no ftp client username username

Syntax Description

username

Name for FTP user.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to specify the username for FTP connections:


RP/0/RSP0/CPU0:router(config)# ftp client username brownfox

Related Commands

Command

Description

ftp client anonymous-password

Assigns a password for anonymous users.

ftp client passive

Configures the software to use only passive File Transfer Protocol (FTP) connections.

ftp client password

Specifies the password for the File Transfer Protocol (FTP) connections.

ftp client source-interface

Specifies the source IP address for File Transfer Protocol (FTP) connections

ping (network)

To check host reachability and network connectivity on IP networks, use the ping command in EXEC mode.

ping [ ipv4 | ipv6 | vrf vrf-name ] [ host-name | ip-address ] [ count number ] [ size number ] [ source { ip-address | type number } ] [ timeout seconds ] [ pattern number ] [ type number ] [ priority number ] [verbose] [donnotfrag] [validate] [sweep]

Syntax Description

ipv4

(Optional) Specifies IPv4 address prefixes.

ipv6

(Optional) Specifies IPv6 address prefixes.

vrf

(Optional) Specifies VPN routing and forwarding (VRF) instance.

vrf-name

(Optional) VRF name of the system to ping.

host-name

(Optional) Hostname of the system to ping.

ip-address

(Optional) IP address of the system to ping.

count number

(Optional) Sets the repeat count. Range is 0 to 2147483647.

size number

(Optional) Sets the datagram size. Range is 36 to 18024

source

(Optional) Identifies the source address or source interface.

type number

(Optional) Sets the type of service. Range is 0 to 255. Available when the ipv4 keyword is specified.

timeout seconds

(Optional) Sets the timeout in seconds. Range is 0 to 3600.

priority number

(Optional) Sets the packet priority. Range is 0 to 15. Available when the ipv6 keyword is specified.

pattern number

(Optional) Sets the data pattern. Range is 0 to 65535.

verbose

(Optional) Sets verbose output.

donnotfrag

(Optional) Sets the Don’t Fragment (DF) bit in the IP header.

validate

(Optional) Validates the return packet.

sweep

(Optional) Sets the sweep ping.

Command Default

No default behavior or values

Command Modes

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The default value for the ping command refers only to the target IP address. No default value is available for the target IP address.

The ping program sends an echo request packet to an address and then waits for 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.


Note


The ping (EXEC) command is supported only on IP networks.


If you enter the command without specifying either a hostname or an IP address, the system prompts you to specify the target IP address and several other command parameters. After specifying the target IP address, you can specify alternate values for the remaining parameters or accept the displayed default for each parameter.

If the system cannot map an address for a hostname, it returns an “%Unrecognized host or address, or protocol not running” error message.

To abnormally terminate a ping session, enter the escape sequence, which is, by default, Ctrl-C. Simultaneously press and release the Ctrl and C keys.

This table describes the test characters sent by the ping facility.

Table 1 ping Test Characters

Character

Description

!

Each exclamation point indicates receipt of a reply.

.

Each period indicates that the network server timed out while waiting for a reply.

?

Unknown packet type.

U

A “destination unreachable” error protocol data unit (PDU) was received.

C

A “congestion experienced” packet was received.

M

Fragmentation is needed, but the “don’t fragment” bit in the IP header is set. When this bit is set, the IP layer does not fragment the packet and returns an Internet Control Message Protocol (ICMP) error message to the source if the packet size is larger than the maximum transmission size. When this bit is not set, the IP layer fragments the packet to forward it to the next hop.

Q

A source quench packet was received.

Task ID

Task ID

Operations

basic-services

read, write, execute

Examples

Although the precise dialog varies somewhat between IPv4 and IPv6, all are similar to the ping session, using default values shown in the following output:

RP/0/RSP0/CPU0:router# ping

Protocol [ipv4]:
Target IP address: 10.0.0.1
Repeat count [5]:
Datagram size [100]:
Timeout in seconds [2]:
Extended commands? [no]: yes
Source address or interface: 10.0.0.2
Type of service [0]:
Set DF bit in IP header? [no]:
Validate reply data? [no]: yes
Data pattern [0xABCD]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Sweep range of sizes? [no]:
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.25.58.21, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 2/11/49 ms

If you enter a hostname or an address on the same line as the ping command, the command performs the default actions appropriate for the protocol type of that hostname or address, as shown in the following output:

RP/0/RSP0/CPU0:routerping server01

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 (5/5), round-trip min/avg/max = 8/8/9 ms

rcp client source-interface

To specify the source IP address for remote copy protocol (rcp) connections, use the rcp client source-interface command in global configuration mode. To remove the rcp client source-interface command from the configuration file and restore the system to its default condition, use the no form of this command.

rcp client source-interface type interface-path-id

no rcp client source-interface type interface-path-id

Syntax Description

type

Interface type. For more information, use the question mark (?) online help function.

interface-path-id

Physical interface or virtual interface.

Note   

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark (?) online help function.

Command Default

The rcp source address is the IP address of the interface used by the rcp packets to leave the networking device.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the rcp client source-interface command to set the IP address of an interface as the source for all rcp connections. To configure the remote username to be used when a remote copy using rcp is requested, use the rcp client username command.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to set the IP address for GigabitEthernet interface 1/0/2/1 as the source address for rcp connections:

RP/0/RSP0/CPU0:router(config)# rcp client source-interface gigabitethernet 1/0/2/1

Related Commands

Command

Description

rcp client username

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

rcp client username

To configure the local user on the client side to be used when requesting a remote copy using remote copy protocol (rcp), use the rcp client username command in global configuration mode. To restore the system to its default condition, use the no form of this command.

rcp client username username

no rcp client username username

Syntax Description

username

Name of the remote user on the rcp server. This name is used for rcp copy requests. If the rcp server has a directory structure, all files and images to be copied are searched for or written relative to the directory in the remote user account.

Command Default

If you do not issue this command, the software sends the remote username associated with the current tty process, if that name is valid, for rcp copy commands. For example, if the user is connected to the networking device through Telnet and the user was authenticated through the username command, the software sends that username as the remote username.

If the username for the current tty process is not valid, the software sends the hostname as the remote username. For rcp boot commands, the software sends the network server hostname by default.


Note


For Cisco, tty lines are commonly used for access services. The concept of tty originated with UNIX. For UNIX systems, each physical device is represented in the file system. Terminals are called tty devices (tty stands for teletype, the original UNIX terminal).


Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Command History

Release

Modification

Release 3.2

This command was supported.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The rcp protocol requires that a client send the remote username on an rcp request to the network server. Use the rcp client username command to specify the remote username to be sent to the network server for an rcp copy request. If the network server has a directory structure, as do UNIX systems, all files and images to be copied are searched for or written relative to the directory in the remote user account. To specify a source address for rcp connections, use the rcp client source-interface command.


Note


The remote username must be associated with an account on the destination server.


Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to configure the remote username to netadmin1:

RP/0/RSP0/CPU0:router(config)# rcp client username netadmin1

Related Commands

Command

Description

rcp client source-interface

Specifies the source IP address for rcp connections.

show cinetd services

To display the services whose processes are spawned by Cinetd when a request is received, use the show cinetd services command in EXEC mode.

show cinetd services

Syntax Description

This command has no keywords or arguments.

Command Default

No default behavior or values

Command Modes

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID

Task ID

Operations

ip-services

read

Examples

The following is sample is output from the show cinetd services command:

RP/0/RSP0/CPU0:router# show cinetd services

Family Service   Proto   Port   ACL  max_cnt  curr_cnt wait  Program Option
============================================================================
v4     telnet    tcp      23 unlimited  0        nowait       telnet
v4     tftp      udp      69 unlimited  0        wait          tftpd   disk0

This table describes the significant fields shown in the display.



Table 2 show cinetd services Command Field Descriptions

Field

Description

Family

Version of the network layer (IPv4 or IPv6).

Service

Network service (for example, FTP, Telnet, and so on).

Proto

Transport protocol used by the service (tcp or udp).

Port

Port number used by the service.

ACL

Access list used to limit the service from some hosts.

max_cnt

Maximum number of concurrent servers allowed for a service.

curr_cnt

Current number of concurrent servers for a service.

wait

Status of whether Cinetd has to wait for a service to finish before serving the next request.

Program

Name of the program for a service.

Option

Service-specific options.

Related Commands

Command

Description

telnet server

Enables Telnet services on a networking device.

tftp server

Enables or disables the TFTP server or a feature running on the TFTP server.

show hosts

To display the default domain name, the style of name lookup service, a list of name server hosts, and the cached list of hostnames and addresses, use the show hosts command in EXEC mode.

show hosts [host-name]

Syntax Description

host-name

(Optional) Name of the host about which to display information. If omitted, all entries in the local cache are displayed.

Command Default

Unicast address prefixes are the default when IPv4 address prefixes are configured.

Command Modes

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID

Task ID

Operations

ip-services

read

Examples

The following is sample output from the show hosts command:

RP/0/RSP0/CPU0:router# show hosts

Default domain is cisco.com
Name/address lookup uses domain service
Name servers are 255.255.255.255
Host              Flags        Age(hr)   Type       Address(es)
host1.cisco.com   (temp, OK)    1         IP         192.168.4.10
abc              (perm, OK)    0         IP         10.0.0.0 10.0.0.2 10.0.0.3

This table describes the significant fields shown in the display.



Table 3 show hosts Command Field Descriptions

Field

Description

Default domain

Default domain used to complete the unqualified hostnames.

Name/address lookup

Lookup is disabled or uses domain services.

Name servers

List of configured name servers.

Host

Hostname.

Flags

Indicates the status of an entry.

  • temp—Temporary entry entered by a name server; the software removes the entry after 72 hours of inactivity.
  • perm—Permanent entry entered by a configuration command; does not time out.
  • OK—Entry is believed to be valid.
  • ??—Entry is considered suspect and subject to revalidation.
  • EX—Entry has expired.

Age(hr)

Number of hours since the software most recently referred to the cache entry.

Type

Type of address (IPv4 or IPv6).

Address(es)

Address of the host. One host may have up to eight addresses.

Related Commands

Command

Description

clear host

Deletes entries from the host-name-and-address cache.

domain list

Defines a list of default domain names to complete unqualified hostnames.

domain lookup disable

Disables the IP DNS-based hostname-to-address translation.

domain name (IPAddr)

Defines a default domain name to complete unqualified hostnames (names without a dotted-decimal domain name).

domain name-server

Specifies the address of one or more name servers to use for name and address resolution.

telnet

To log in to a host that supports Telnet, use the telnet command in EXEC mode.

telnet [ vrf { vrf-name | default } ] { ip-address | host-name } [options]

Syntax Description

vrf

(Optional) Specifies a VPN routing and forwarding (VRF) instance

vrf-name

VRF name of the system to ping.

default

Specifies the default VRF instance.

ip-address

IP address of a specific host on a network.

  • IPv4 address format—Must be entered in the (x.x.x.x) format.
  • IPv6 address format— Must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

host-name

Name of a specific host on a network.

options

(Optional) Telnet connection options. See Table 1for a list of supported options.

Command Default

Telnet client is in Telnet connection options nostream mode.

Command Modes

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

If the Telnet server is enabled, you should be able to start a Telnet session as long as you have a valid username and password.

This table lists the supported Telnet connection options.



Table 4 Telnet Connection Options

Option

Description

/stream

Turns on stream processing, which enables a raw TCP stream with no Telnet control sequences. A stream connection does not process Telnet options and can be appropriate for connections to ports running UNIX-to-UNIX copy program (UUCP) and other non-Telnet protocols.

/nostream

Turns off stream processing.

port number

Port number. Range is 0 to 65535.

/source-interface

Specifies source interface.

To display a list of the available hosts, use the show hosts command. To display the status of all TCP connections, use the show tcp command.

The software assigns a logical name to each connection, and several commands use these names to identify connections. The logical name is the same as the hostname, unless that name is already in use or you change the connection name with the name-connection EXEC command. If the name is already in use, the software assigns a null name to the connection.

The Telnet software supports special Telnet commands in the form of Telnet sequences that map generic terminal control functions to operating system-specific functions. To issue a special Telnet command, enter the escape sequence and then a command character. The default escape sequence is Ctrl-^ (press and hold the Control and Shift keys and the 6 key). You can enter the command character as you hold down Ctrl or with Ctrl released; you can use either uppercase or lowercase letters. Table 2 lists the special Telnet escape sequences.

Table 5 Special Telnet Escape Sequences

Escape Sequence1

Purpose

Ctrl-^ c

Interrupt Process (IP).

Ctrl-^ o

Abort Output (AO).

Ctrl-^ u

Erase Line (EL).

1 The caret (^) symbol refers to Shift-6 on your keyboard.

At any time during an active Telnet session, you can list the Telnet commands by pressing the escape sequence keys followed by a question mark at the system prompt:

ctrl-^?

A sample of this list follows. In this sample output, the first caret (^) symbol represents the Control key, and the second caret represents Shift-6 on your keyboard:

RP/0/RSP0/CPU0:router# ^^?

[Special telnet escape help]
^^B  sends telnet BREAK
^^C  sends telnet IP
^^H  sends telnet EC
^^O  sends telnet AO
^^T  sends telnet AYT
^^U  sends telnet EL 

You can have several concurrent Telnet sessions open and switch among them. To open a subsequent session, first suspend the current connection by pressing the escape sequence (Ctrl-Shift-6 and then x [Ctrl^x] by default) to return to the system command prompt. Then open a new connection with the telnet command.

To terminate an active Telnet session, issue any of the following commands at the prompt of the device to which you are connecting:

  • close
  • disconnect
  • exit
  • logout
  • quit

Task ID

Task ID

Operations

basic-services

read, write, execute

Examples

The following example shows how to establish a Telnet session to a remote host named host1:

RP/0/RSP0/CPU0:router# telnet host1

Related Commands

Command

Description

aaa authentication login default local

Sets AAA authentication at login. For more information, see Cisco ASR 9000 Series Aggregation Services Router System Management Command Reference.

telnet server

Enables Telnet services on a networking device.

terminal length

Sets the number of lines on the current terminal screen for the current session. For more information, see Cisco ASR 9000 Series Aggregation Services Router System Management Command Reference.

terminal width

Sets the number of character columns on the terminal screen for the current session. For more information, see Cisco ASR 9000 Series Aggregation Services Router System Management Command Reference.

telnet client source-interface

To specify the source IP address for a Telnet connection, use the telnet client source-interface command in global configuration mode. To remove the telnet client source-interface command from the configuration file and restore the system to its default condition, use the no form of this command.

telnet { ipv4 | ipv6 } client source-interface type interface-path-id

no telnet client source-interface type interface-path-id

Syntax Description

ipv4

Specifies IPv4 address prefixes.

ipv6

Specifies IPv6 address prefixes.

type

Interface type. For more information, use the question mark (?) online help function.

interface-path-id

Physical interface or virtual interface.

Note   

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark (?) online help function.

Command Default

The IP address of the best route to the destination is used as the source IP address.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the telnet client source-interface command to set the IP address of an interface as the source for all Telnet connections.

Task ID

Task ID

Operations

ipv4

read, write

ip-services

read, write

Examples

The following example shows how to set the IP address for GigabitEthernet interface 1/0/2/1 as the source address for Telnet connections:

RP/0/RSP0/CPU0:router(config)# telnet ipv4 client source-interface gigabitethernet 1/0/2/1

Related Commands

Command

Description

telnet server

Enables Telnet services on a networking device.

telnet dscp

To define the differentiated services code point (DSCP) value and IPv4 precedence to specifically set the quality-of-service (QoS) marking for Telnet traffic on a networking device, use the telnet dscp command in global configuration mode. To disable DSCP, use the no form of this command.

telnet [ vrf { vrf-name | default } ] ipv4 dscp dscp-value

no telnet [ vrf { vrf-name | default } ] ipv4 dscp dscp-value

Syntax Description

vrf

(Optional) Specifies a VPN routing and forwarding (VRF) instance.

vrf-name

(Optional) VRF name of the system to ping.

default

(Optional) Specifies the default VRF instance.

ipv4

Specifies IPv4 address prefixes.

dscp-value

Value for DSCP. The range is from 0 to 63. The default value is 0.

Command Default

If DSCP is disabled or not configured, the following default values are listed:

  • The default value for the server 16.
  • The default value for the client is 0.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

IPv4 is the supported protocol for defining a DSCP value for locally originated Telnet traffic.

DSCP can impact both server and client behavior of the specific VRF.

Task ID

Task ID

Operations

ipv4

read, write

ip-services

read, write

Examples

The following example shows how to define the DSCP value and IPv4 precedence:

RP/0/RSP0/CPU0:router(config)# telnet vrf default ipv4 dscp 40
RP/0/RSP0/CPU0:router(config)# telnet vrf default ipv4 dscp 10

Related Commands

Command

Description

telnet

Logs in to a host that supports Telnet.

telnet server

To enable Telnet services on a networking device, use the telnet server command in global configuration mode. To disable Telnet services, use the no form of this command.

telnet [ vrf { vrf-name | default } ] { ipv4 | ipv6 } server max-servers { no-limit | limit } [ access-list list-name ]

no telnet [ vrf { vrf-name | default } ] { ipv4 | ipv6 } server max-servers { no-limit | limit } [ access-list list-name ]

Syntax Description

vrf

(Optional) Specifies VPN routing and forwarding (VRF) instance.

vrf-name

(Optional) VRF name of the system to ping.

default

(Optional) Specifies the default VRF instance.

ipv4

Specifies IPv4 address prefixes.

ipv6

Specifies IPv6 address prefixes.

max-servers

Sets the number of allowable Telnet servers.

no-limit

Specifies that there is no maximum number of allowable Telnet servers.

limit

Specifies the maximum number of allowable Telnet servers. Range is 1 to 200.

access-list

(Optional) Specifies an access list.

list-name

(Optional) Access list name.

Command Default

Telnet services are disabled.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Disable Telnet services to prevent inbound Telnet connections from being accepted into a networking device using the telnet command. After Telnet services are disabled, no new inbound connections are accepted, and the Cisco Internet services daemon (Cinetd) stops listening on the Telnet port.

Enable Telnet services by setting the max-servers keyword to a value of one or greater. This allows inbound Telnet connections into a networking device.

This command affects only inbound Telnet connections to a networking device. Outgoing Telnet connections can be made regardless of whether Telnet services are enabled.

Using the no form of the command disables the Telnet connection and restores the system to its default condition.


Note


Before establishing communications with the router through a Telnet session, configure the telnet server and vty-pool functions (see the Cisco ASR 9000 Series Aggregation Services Router System Management Command Reference , the Cisco ASR 9000 Series Aggregation Services Router System Management Configuration Guide, and Cisco ASR 9000 Series Aggregation Services Router IP Addresses and Services Configuration Guide).


Task ID

Task ID

Operations

ipv4

read, write

ip-services

read, write

Examples

The following example shows how to enable Telnet services for one server:

RP/0/RSP0/CPU0:router(config)# telnet ipv4 server max-servers 1

Related Commands

Command

Description

telnet

Logs in to a host that supports Telnet.

telnet transparent

To send a Carriage Return (CR) as a CR-NULL rather than a Carriage Return-Line Feed (CR-LF) for virtual terminal sessions, use the telnet transparent command in line template submode. To remove the telnet transparent command from the configuration file and restore the system to its default condition, use the no form of this command.

telnet transparent

no telnet transparent

Syntax Description

This command has no keywords or arguments.

Command Default

No default behavior or values

Command Modes

Line console

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The telnet transparent command is useful for coping with different interpretations of end-of-line handling in the Telnet protocol specification.

Task ID

Task ID

Operations

tty-access

read, write

Examples

The following example shows how to configure the vty line to operate in Telnet transparent mode so that when the carriage return key is pressed the system sends the signal as a CR-NULL key combination rather than a CR-LF key combination:

RP/0/RSP0/CPU0:router(config)# line console 
RP/0/RSP0/CPU0:router(config-line)# telnet transparent

Related Commands

Command

Description

telnet

Logs in to a host that supports Telnet.

tftp client source-interface

To specify the source IP address for a TFTP connection, use the tftp client source-interface command in global configuration mode. To remove the tftp client source-interface command from the configuration file and restore the system to its default condition, use the no form of this command.

tftp client source-interface type interface-path-id

no tftp client source-interface type interface-path-id

Syntax Description

type

Interface type. For more information, use the question mark (?) online help function.

interface-path-id

Physical interface or virtual interface.

Note   

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark (?) online help function.

Command Default

The IP address of the best route to the destination is used as the source IP address.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Use the tftp client source-interface command to set the IP address of an interface as the source for all TFTP connections.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to set the IP address for GigabitEthernet interface 1/0/2/1 as the source address for TFTP connections:

RP/0/RSP0/CPU0:router(config)# tftp client source-interface gigabitethernet 1/0/2/1

Related Commands

Command

Description

tftp server

Enables or disables the TFTP server or a feature running on the TFTP server.

tftp server

To enable or disable the TFTP server or a feature running on the TFTP server, use the tftp server command in global configuration mode. To restore the system to its default condition, use the no form of this command.

tftp { ipv4 | ipv6 } server homedir tftp-home-directory [ max-servers [ number | no-limit ] ] [ access-list name ]

no tftp { ipv4 | ipv6 } server homedir tftp-home-directory [ max-servers [ number | no-limit ] ] [ access-list name ]

Syntax Description

ipv4

Specifies IPv4 address prefixes.

ipv6

Specifies IPv6 address prefixes.

homedir tftp-home-directory

Specifies the home directory.

max-servers number

(Optional) Sets the maximum number of concurrent TFTP servers. The range is from 1 to 2147483647.

max-servers no-limit

(Optional) Sets no limit to process a number of allowable TFTP server.

access-list name

(Optional) Specifies the name of the access list associated with the TFTP server.

Command Default

The TFTP server is disabled by default. When not specified, the default value for the max-servers keyword is unlimited.

Command Modes

Global configuration

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Using the no form of the tftp server command removes the specified command from the configuration file and restores the system to its default condition. The no form of the command is not stored in the configuration file.

Task ID

Task ID

Operations

ipv4

read, write

ip-services

read, write

Examples

The following example shows that the TFTP server is enabled for the access list named test:

RP/0/RSP0/CPU0:router(config)# tftp ipv4 server homedir disk0 access-list test 

Related Commands

Command

Description

show cinetd services

Displays the services whose processes are spawned by cinetd.

traceroute

To discover the routes that packets actually take when traveling to their destination across an IP network, use the traceroute command in EXEC mode.

traceroute [ ipv4 | ipv6 | vrf vrf-name ] [ host-name | ip-address ] [ source ip-address-name ] [numeric] [ timeout seconds ] [ probe count ] [ minttl seconds ] [ maxttl seconds ] [ port number ] [ priority number ] [verbose]

Syntax Description

ipv4

(Optional) Specifies IPv4 address prefixes.

ipv6

(Optional) Specifies IPv6 address prefixes.

vrf

(Optional) Specifies VPN routing and forwarding (VRF) instance.

vrf-name

(Optional) VRF name of the system to ping.

host-name

(Optional) Hostname of system to use as the destination of the trace attempt.

ip-address

(Optional) Address of system to use as the destination of the trace attempt.

source

(Optional) Source address.

ip-address-name

(Optional) IP address A.B.C.D or hostname.

numeric

(Optional) Numeric display only.

timeout seconds

(Optional) Timeout value. Range is 0 to 3600.

probe count

(Optional) Probe count. Range is 0 to 65535.

minttl seconds

(Optional) Minimum time to live. Range is 0 to 255.

maxttl seconds

(Optional) Maximum time to live. Range is 0 to 255.

port number

(Optional) Port number. Range is 0 to 65535.

priority number

(Optional) Packet priority. Range is 0 to 15. Available when the ipv6 keyword is specified.

verbose

(Optional) Verbose output.

Command Default

No default behavior or values

Command Modes

Command History

Release

Modification

Release 3.7.2

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

The default value for the traceroute command refers only to the destination. No default value is available for the destination address.

The traceroute command works by taking advantage of the error messages generated by networking devices when a datagram exceeds its time-to-live (TTL) value.

The traceroute command starts by sending probe datagrams with a TTL value of 1, which causes the first networking device to discard the probe datagram and send back an error message. The traceroute command sends several probes at each TTL level and displays the round-trip time for each.

The traceroute command sends out one probe at a time. Each outgoing packet may result in one or two error messages. A “time-exceeded” error message indicates that an intermediate networking device has seen and discarded the probe. A “destination-unreachable” error message indicates that the destination node has received the probe and discarded it because it could not deliver the packet. If the timer goes off before a response comes in, the traceroute command prints an asterisk (*).

The traceroute command terminates when the destination responds, when the maximum TTL is exceeded, or when the user interrupts the trace with the escape sequence, which is, by default, Ctrl-C. Simultaneously press and release the Ctrl and C keys.

To use nondefault parameters and invoke an extended traceroute test, enter the command without a host-name or ip- address argument. You are stepped through a dialog to select the desired parameter values for the traceroute test.

Because of how IP is implemented on various networking devices, the IP traceroute command may behave in unexpected ways.

Not all destinations respond correctly to a probe message by sending back an “ICMP port unreachable” message. A long sequence of TTL levels with only asterisks, terminating only when the maximum TTL has been reached, may indicate this problem.

There is a known problem with the way some hosts handle an “ICMP TTL exceeded” message. Some hosts generate an “ICMP” message, but they reuse the TTL of the incoming packet. Because this value is zero, the ICMP packets do not succeed in returning. When you trace the path to such a host, you may see a set of TTL values with asterisks (*). Eventually the TTL is raised high enough that the “ICMP” message can get back. For example, if the host is six hops away, the traceroute command times out on responses 6 through 11.

Task ID

Task ID

Operations

basic-services

read, write, execute

Examples

The following output shows a sample traceroute session when a destination hostname has been specified:

RP/0/RSP0/CPU0:routertraceroute host8-sun

Type escape sequence to abort.
Tracing the route to 192.168.0.73
 1 192.168.1.6 (192.168.1.6) 10 msec 0 msec 10 msec
 2 gateway01-gw.gateway.cisco.com (192.168.16.2) 0 msec 10 msec 0 msec
 3 host8-sun.cisco.com (192.168.0.73) 10 msec * 0 msec

The following display shows a sample extended traceroute session when a destination hostname is not specified:

traceroute# traceroute

Protocol [ipv4]:
Target IP address: ena-view3
Source address: 10.0.58.29
Numeric display? [no]:
Timeout in seconds [3]:
Probe count [3]:
Minimum Time to Live [1]:
Maximum Time to Live [30]:
Port Number [33434]:
Loose, Strict, Record, Timestamp, Verbose[none]:

Type escape sequence to abort.
Tracing the route to 171.71.164.199
 1  sjc-jpxlnock-vpn.cisco.com (10.25.0.1) 30 msec  4 msec  4 msec
 2  15lab-vlan725-gx1.cisco.com (173.19.72.2) 7 msec  5 msec  5 msec
 3  stc15-00lab-gw1.cisco.com (173.24.114.33) 5 msec  6 msec  6 msec
 4  stc5-lab4-gw1.cisco.com (173.24.114.89) 5 msec  5 msec  5 msec
 5  stc5-sbb4-gw1.cisco.com (172.71.241.162) 5 msec  6 msec  6 msec
 6  stc5-dc5-gw1.cisco.com (172.71.241.10) 6 msec  6 msec  5 msec
 7  stc5-dc1-gw1.cisco.com (172.71.243.2) 7 msec  8 msec  8 msec
 8  ena-view3.cisco.com (172.71.164.199) 6 msec  *  8 msec

This table describes the characters that can appear in traceroute output.



Table 6 traceroute Text Characters

Character

Description

xx msec

For each node, the round-trip time in milliseconds for the specified number of probes.

*

Probe time out.

?

Unknown packet type.

A

Administratively unreachable. This output usually indicates that an access list is blocking traffic.

H

Host unreachable.

N

Network unreachable.

P

Protocol unreachable.

Q

Source quench.

U

Port unreachable.