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Cisco IOS XR IP Addresses and Services Command Reference, Release 3.2
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Preface
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Access List Commands on Cisco IOS XR Software
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ARP Commands on Cisco IOS XR Software
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Cisco Express Forwarding Commands on Cisco IOS XR Software
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DHCP Commands on Cisco IOS XR Software
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Host Services and Applications Commands on Cisco IOS XR Software
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HSRP Commands on Cisco IOS XR Software
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LPTS Commands on Cisco IOS XR Software
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Network Stack IPv4 and IPv6 Commands on Cisco IOS XR Software
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Prefix List Commands on Cisco IOS XR Software
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Transport Stack Commands on Cisco IOS XR Software
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VRRP Commands on Cisco IOS XR Software
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Index
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Table Of Contents
Host Services and Applications Commands on Cisco IOS XR Software
telnet client source-interface
Host Services and Applications Commands on Cisco IOS XR Software
This document describes the commands used to configure and monitor host services and applications, such as Domain Name System (DNS), Telnet, File Transfer Protocol (FTP), Trivial File Transfer Protocol (TFTP), and rcp on Cisco IOS XR software.
For detailed information about host services and applications concepts, configuration tasks, and examples, see the Cisco IOS XR 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
Defaults
One service request per second is accepted.
Command Modes
Global configuration
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Any service request that exceeds the rate limit is rejected. The rate limit is applied to individual applications.
Examples
The following example shows the cinetd rate-limit being set to 10:
RP/0/RP0/CPU0:router# configRP/0/RP0/CPU0:router(config)# cinetd rate-limit 10clear 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
Defaults
No static mapping is configured.
Command Modes
EXEC
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
The hostname entries are not removed from NVRAM but are cleared in running memory.
Only the temporary entries in the cache are cleared; the permanent entries that were entered with the domain ipv4 host or the domain ipv6 host commands are not cleared.
Examples
The following example shows how to clear all temporary entries from the hostname-and-address cache:
RP/0/RP0/CPU0:router# clear host *Related Commands
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 v4address1 [v4address2...v4address8]
no domain ipv4 host host-name v4address1
Syntax Description
Defaults
No static mapping is configured.
Command Modes
Global configuration
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
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.
Examples
The following example shows how to define two IPv4 static mappings:
RP/0/RP0/CPU0:router(config)# domain ipv4 host host1 192.168.7.18RP/0/RP0/CPU0:router(config)# domain ipv4 host bost2 10.2.0.2 192.168.7.33domain 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
Defaults
No static mapping is configured. IPv6 address prefixes are not enabled.
Command Modes
Global configuration
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
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.
Examples
The following example shows how to define two IPv6 static mappings:
RP/0/RP0/CPU0:router(config)# domain ipv6 host host1 192.168.7.18RP/0/RP0/CPU0:router(config)# domain ipv6 host host2 10.2.0.2 192.168.7.33domain 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.
Defaults
No domain names are defined.
Command Modes
Global configuration
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
If there is no domain list, the domain name that you specified with the domain name 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 command, except that you can use the domain list command to define a list of domains, each to be tried in turn.
Examples
The following example shows how to add several domain names to a list:
RP/0/RP0/CPU0:router(config)# domain list domain1.comRP/0/RP0/CPU0:router(config)# domain list domain2.eduThe following example shows how to add a name to and then delete a name from the list:
RP/0/RP0/CPU0:router(config)# domain list domain3.eduRP/0/RP0/CPU0:router(config)# no domain list domain2.eduRelated Commands
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 arguments or keywords.
Defaults
The IP DNS-based host-to-address translation is enabled.
Command Modes
Global configuration
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
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.
Examples
The following example shows how to enable the IP DNS-based hostname-to-address translation:
RP/0/RP0/CPU0:router(config)# domain lookup disableRelated Commands
domain name
To define a default domain name that the software uses to complete unqualified hostnames, use the domain name command in global configuration 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.
Defaults
There is no default domain name.
Command Modes
Global configuration
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
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.
Examples
The following example shows how to define cisco.com as the default domain name:
RP/0/RP0/CPU0:router(config)# domain name cisco.comRelated Commands
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
Defaults
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 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
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.
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/RP0/CPU0:router(config)# domain name-server 192.168.1.111RP/0/RP0/CPU0:router(config)# domain name-server 192.168.1.2Related Commands
Disables the domain lookup.
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
Command Modes
Global configuration
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
The ftp client anonymous-password command is FTP server dependent.
Examples
The following example shows how to set the anonymous password to xxxx:
RP/0/RP0/CPU0:router(config)# ftp client anonymous-password xxxxftp client passive
To configure the software to use only passive 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 arguments or keywords.
Defaults
FTP data connections are active.
Command Modes
Global configuration
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
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.
Examples
The following example shows how to configure the networking device to use only passive FTP connections:
RP/0/RP0/CPU0:router(config)# ftp client passive1d: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
ftp client source-interface
To specify the source IP address for 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 instance
no ftp client source-interface type instance
Syntax Description
Defaults
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 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
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.
Examples
The following example shows how to configure the IP address associated with Packet-over-SONET (PoS) 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/RP0/CPU0:router(config)# ftp client source-interface POS 0/1/2/1Related Commands
ping (EXEC)
To check host reachability and network connectivity on IP networks, use the ping command in EXEC mode.
ping [ipv4 | ipv6] [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
Defaults
No default behavior or values.
Command Modes
EXEC
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
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.
Table 27 describes the test characters sent by the ping facility.
Note
Examples
If you do not enter a hostname or an address on the same line as the ping command, 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. Although the precise dialog varies somewhat from protocol to protocol, all are similar to the ping session, using default values shown in the following output:
RP/0/RP0/CPU0:router# pingProtocol [ipv4]:Target IP address: 10.0.0.1Repeat count [5]:Datagram size [100]:Timeout in seconds [2]:Extended commands? [no]: yesSource address or interface: 10.0.0.2Type of service [0]:Set DF bit in IP header? [no]:Validate reply data? [no]: yesData 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 msIf 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/RP0/CPU0:router# ping server01Type 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 msrcp 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 instance
no rcp client source-interface type instance
Syntax Description
Defaults
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 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
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.
Examples
The following example shows how to set the IP address for Packet-over-SONET (PoS) interface 1/0/2/1 as the source address for rcp connections:
RP/0/RP0/CPU0:router(config)# rcp client source-interface POS 1/0/2/1Related Commands
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
Defaults
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
Command Modes
Global configuration
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
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
Examples
The following example shows how to configure the remote username to netadmin1:
RP/0/RP0/CPU0:router(config)# rcp client username netadmin1Related Commands
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 arguments or keywords.
Defaults
No default behavior or values.
Command Modes
EXEC
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Examples
The following is sample is output from the show cinetd services command:
RP/0/RP0/CPU0:router# show cinetd servicesFamily Service Proto Port ACL max_cnt curr_cnt wait Program Option============================================================================v4 telnet tcp 23 unlimited 0 nowait telnetv4 tftp udp 69 unlimited 0 wait tftpd disk0Table 28 describes the significant fields shown in the display.
Related Commands
telnet ipv4 server
Enables Telnet services on a networking device.
tftp ipv4 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.
Defaults
Unicast address prefixes are the default when IPv4 address prefixes are configured.
Command Modes
EXEC
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Examples
The following is sample output from the show hosts command:
RP/0/RP0/CPU0:router# show hostsDefault domain is cisco.comName/address lookup uses domain serviceName servers are 255.255.255.255Host Flags Age(hr) Type Address(es)host1.cisco.com (temp, OK) 1 IP 192.168.4.10abc (perm, OK) 0 IP 10.0.0.0 10.0.0.2 10.0.0.3Table 29 describes the significant fields shown in the display.
Related Commands
telnet
To log in to a host that supports Telnet, use the telnet command in EXEC mode.
telnet {ip-address | host-name} [options]
Syntax Description
ip-address
IP address of a specific host on a network.
•
•
host-name
Name of a specific host on a network.
options
(Optional) Telnet connection options. See Table 30 for a list of supported options.
Defaults
Telnet client is in telnet connection options nostream mode.
Command Modes
EXEC
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
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.
Table 30 lists the supported Telnet connection options.
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 31 lists the special Telnet escape sequences.
Table 31 Special Telnet Escape Sequences
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/RP0/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 ELYou 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:
•
•
•
•
•
Examples
The following example shows how to establish a Telnet session to a remote host named host1:
RP/0/RP0/CPU0:router# telnet host1Related Commands
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 instance
no telnet client source-interface type instance
Syntax Description
Defaults
The IP address of the best route to the destination is used as the source IP address.
Command Modes
Global configuration
Command History
Release 3.2
This command was introduced on the Cisco CRS-1 and Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Use the telnet client source-interface command to set the IP address of an interface as the source for all Telnet connections.
Examples
The following example shows how to set the IP address for Packet-over-SONET (PoS) interface 1/0/2/1 as the source address for Telnet connections:
RP/0/RP0/CPU0:router(config)# telnet ipv4 client source-interface POS 1/0/2/1Related Commands
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 {ipv4 | ipv6} server max-servers {limit | no-limit}
no telnet {ipv4 | ipv6} server max-servers {limit | no-limit}
Syntax Description
Defaults
Telnet services are disabled.
Command Modes
Global configuration
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
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.
Examples
The following example shows how to enable Telnet services for one server:
RP/0/RP0/CPU0:router(config)#telnet ipv4 server max-servers 1Related Commands
telnet transparent
To send a CR (carriage return) as a CR-NULL rather than a CR-LF (carriage return-line feed) 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 arguments or keywords.
Command Modes
Line template submode
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
The telnet transparent command is useful for coping with different interpretations of end-of-line handling in the Telnet protocol specification.
Examples
The following example shows how to configure the vty line to operate in Telnet transparent mode, wherein any carriage return key is sent as a CR-NULL key combination rather than a CR-LF key combination:
RP/0/RP0/CPU0:router(config)# line consoleRP/0/RP0/CPU0:router(config-line)# telnet transparentRelated Commands
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 instance
no tftp client source-interface type instance
Syntax Description
Defaults
The IP address of the best route to the destination is used as the source IP address.
Command Modes
Global configuration
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Use the tftp client source-interface command to set the IP address of an interface as the source for all TFTP connections.
Examples
The following example shows how to set the IP address for Packet-over-SONET (PoS) interface 1/0/2/1 as the source address for TFTP connections:
RP/0/RP0/CPU0:router(config)# tftp client source-interface POS 1/0/2/1Related Commands
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] [access-list name]
no tftp {ipv4 | ipv6} server {homedir tftp-home-directory} [max-servers number] [access-list name]
Syntax Description
Defaults
The TFTP server is disabled by default.
Command Modes
Global configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
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.
Examples
The following example shows that the TFTP server is enabled for the access list named test:
RP/0/RP0/CPU0:router(config)# tftp ipv4 server access-list test homedir disk0Related Commands
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] [host-name | ip-address] [source ip-address-name] [numeric] [timeout seconds] [probe count] [minttl seconds] [maxttl seconds] [port number] [priority number] [verbose]
Syntax Description
Defaults
No default behavior or values.
Command Modes
EXEC
Command History
Release 2.0
This command was introduced on the Cisco CRS-1.
Release 3.0
No modification.
Release 3.2
This command was supported on the Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
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.
Common Trace Problems
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, traceroute times out on responses 6 through 11.
Examples
The following output shows a sample traceroute session when a destination hostname has been specified:
RP/0/RP0/CPU0:router# traceroute host8-sunType escape sequence to abort.Tracing the route to 192.168.0.731 192.168.1.6 (192.168.1.6) 10 msec 0 msec 10 msec2 gateway01-gw.gateway.cisco.com (192.168.16.2) 0 msec 10 msec 0 msec3 host8-sun.cisco.com (192.168.0.73) 10 msec * 0 msecThe following display shows a sample extended traceroute session when a destination hostname is not specified:
RP/0/RP0/CPU0:router# tracerouteProtocol [ipv4]:Target IP address: ena-view3Source address: 10.0.58.29Numeric 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 171.71.164.1991 sjc-jpxlnock-vpn.cisco.com (10.25.0.1) 30 msec 4 msec 4 msec2 15lab-vlan725-gx1.cisco.com (173.19.72.2) 7 msec 5 msec 5 msec3 stc15-00lab-gw1.cisco.com (173.24.114.33) 5 msec 6 msec 6 msec4 stc5-lab4-gw1.cisco.com (173.24.114.89) 5 msec 5 msec 5 msec5 stc5-sbb4-gw1.cisco.com (172.71.241.162) 5 msec 6 msec 6 msec6 stc5-dc5-gw1.cisco.com (172.71.241.10) 6 msec 6 msec 5 msec7 stc5-dc1-gw1.cisco.com (172.71.243.2) 7 msec 8 msec 8 msec8 ena-view3.cisco.com (172.71.164.199) 6 msec * 8 msecTable 32 describes the characters that can appear in traceroute output.
