Configuring Telnet
This chapter describes how to configure Telnet and includes the following topics:
•Information About the Telnet Server
•Prerequisites for Telnet
•Guidelines and Limitations
•Default Setting
•Configuring Telnet
•Verifying the Telnet Configuration
•Additional References
•Feature History for Telnet
Information About the Telnet Server
The Telnet protocol enables you to set up TCP/IP connections to a host. Telnet allows a person at one site to establish a TCP connection to a login server at another site and then passes the keystrokes from one device to the other. Telnet can accept either an IP address or a domain name as the remote device address.
Prerequisites for Telnet
Telnet has the following prerequisites:
•You have configured IP on a Layer 3 interface, out-of-band on the mgmt 0 interface, or inband on an Ethernet interface.
Guidelines and Limitations
•The Telnet server is enabled by default.
•Cisco NX-OS commands may differ from Cisco IOS commands.
Default Setting
The following table lists the default setting for Telnet.
Configuring Telnet
This section includes the following topics:
•Enabling the Telnet Server
•Starting an IP Telnet Session to a Remote Device
•Clearing Telnet Sessions
Enabling the Telnet Server
Use this procedure to enable the Telnet server. The Telnet server is enabled by default, but you can use this procedure to re-enable it if necessary.
BEFORE YOU BEGIN
Before beginning this procedure, you must know or do the following:
•You are logged in to the CLI in EXEC mode.
•By default, the Telnet server is enabled.
SUMMARY STEPS
1. config t
2. feature telnet
3. exit
4. show telnet server
5. copy running-config startup-config
DETAILED STEPS
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Step 1 |
config t Example: n1000v# config t n1000v(config)# |
Places you into CLI Global Configuration mode. |
Step 2 |
feature telnet Example: n1000v(config)# feature telnet n1000v(config)# |
Enables the Telnet server. |
Step 3 |
show telnet server Example: n1000v(config)# show telnet server telnet service enabled n1000v(config)# |
(Optional) Displays the Telnet server configuration. |
Step 4 |
copy running-config startup-config Example: n1000v(config)# copy running-config startup-config |
(Optional) Copies these changes made in the running configuration to the startup configuration. |
Starting an IP Telnet Session to a Remote Device
Use this procedure to start a Telnet session to a remote device.
BEFORE YOU BEGIN
Before beginning this procedure, you must know or do the following.
•You are logged in to the CLI in EXEC mode.
•You have verified that the Telnet server is enabled on the remote device.
•You have already obtained the hostname for the remote device and, if needed, the username on the remote device.
•You have already verified that the Telnet server is enabled. If not you have enabled it using the "Enabling the Telnet Server" procedure. By default, the Telnet server is enabled.
SUMMARY STEPS
1. telnet {ip address | hostname} [port-number] [vrf vrf-name]
DETAILED STEPS
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Step 1 |
telnet {ip address | host-name} [port-number] [vrf vrf-name] Example: n1000v# telnet 10.10.1.1 |
Creates an IP Telnet session to the specified destination. port-number: The port number, from 1 to 65535, to use for this session. The default port number is 23. vrf-name: The default VRF is the default VRF. |
Clearing Telnet Sessions
Use this procedure to clear Telnet sessions.
BEFORE YOU BEGIN
Before beginning this procedure, you must know or do the following.
•You are logged in to the CLI in EXEC mode.
SUMMARY STEPS
1. show users
2. clear line vty-line
DETAILED STEPS
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Step 1 |
show users Example:
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Displays user session information. |
Step 2 |
clear line vty-line Example:
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Clears a user Telnet session. |
Step 3 |
show users Example:
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Displays user session information. |
Example:
NAME LINE TIME IDLE PID COMMENT
admin tty1 Jul 25 19:13 old 2867
admin pts/1 Jul 28 14:04 . 31453 (::ffff:171.70.209.8)
admin pts/2 Jul 28 14:04 . 31475 (171.70.209.8)*
NAME LINE TIME IDLE PID COMMENT
admin tty1 Jul 25 19:13 old 2867
admin pts/2 Jul 28 14:04 . 31475 (171.70.209.8)*
Verifying the Telnet Configuration
To display the Telnet configuration information, use one of the following commands:
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show running-config security [all] |
Displays the user account configuration in the running configuration. The all keyword displays the default values for the user accounts. |
show telnet server |
Displays the telnet server configuration. |
show hosts |
Displays the configuration details for current hosts. |
show tcp connection |
Displays connection information. |
Example:
n1000v# show running-config security all
username admin password 5 $1$xMw2Q/1S$ZEWRvyAxAJAFV0weuSPvg1 role network-admin
username user2 password 5 $1$byNNnnSP$xfXVKjE5UEScvriwX3Kyj0 role network-operator
username user2 sshkey ssh-rsa
AAAAB3NzaC1yc2EAAAABIwAAAQEAyKcb7Nv9Ki1OOId9/tdHHa/ngQujlvK5mXyL/n+DeOXKfVhHbX2a+V0cm7CCLU
kBh+BvZRmpmOVTmU/5awfVhVxMKXMiPOPBc+A6/n3FVroyRwupMki6mW
oM6UwaGID5gsVPqFjFNSgMWtbhjo97XVKhgjFW+wOVt8QoAcrEtnwEfsnQk1EIr/0XIP1mqTsrqTsmjZ2vLk+fFzTG
YAxMvYZI+BrN47aoH2ywS7CpnODjCDXJuDYSPbc3PA8t0ghU/60m9R+s6AZPuljVQbGfxPrahEu4GVc6sMJNU1
JxmqDJkodhMArObB4Umzj7E3Rdby/ZWx/clTYiXQR1X1VfhQ==
banner motd # User Access Verification #
Additional References
For additional information related to implementing Telnet, see the following sections:
•Related Documents
•Standards
Related Documents
Standards
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No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature. |
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Feature History for Telnet
This section provides the Telnet release history.
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Telnet |
4.0(4)SV1(1) |
This feature was introduced. |