Contents

• Configuring Telnet
• Information About the Telnet Server
• Prerequisites for Telnet
• Guidelines and Limitations for Telnet
• Default Setting for Telnet
• Configuring Telnet
• Enabling the Telnet Server
• Starting an IP Telnet Session to a Remote Device
• Clearing Telnet Sessions
• Verifying the Telnet Configuration
• Feature History for Telnet

Configuring Telnet

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This chapter contains the following sections:

• Information About the Telnet Server
• Prerequisites for Telnet
• Guidelines and Limitations for Telnet
• Default Setting for Telnet
• Configuring Telnet
• Verifying the Telnet Configuration
• 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

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 for Telnet

• The Telnet server is disabled by default
• Cisco NX-OS commands may differ from Cisco IOS commands.

Default Setting for Telnet

Parameter	Default
Telnet server	Enabled

Configuring Telnet

Enabling the Telnet Server

The Telnet server is enabled by default, but you can use this procedure to reenable it if necessary.

Before You Begin

Before beginning this procedure, you must be logged in to the CLI in EXEC mode.

Procedure

	Command or Action	Purpose
Step 1	switch# configure terminal	Places you into global configuration mode.
Step 2	switch(config)# feature telnet	Enables the Telnet server.
Step 3	switch(config)# show telnet server	Enables the Telnet server.
Step 4	switch(config)# show telnet server	(Optional) Displays the Telnet server configuration.
Step 5	switch(config)# copy running-config startup-config	(Optional) Copies the running configuration to the startup configuration.

switch# configure terminal
switch(config)# feature telnet
switch(config)# show telnet server
telnet service enabled
switch(config)# copy running-config startup-config

Starting an IP Telnet Session to a Remote Device

Before You Begin

Before beginning this procedure, you must have done the following:

• Logged in to the CLI in EXEC mode
• Verified that the Telnet server is enabled and it is also enabled on the remote device
• Obtained the hostname for the remote device and, if needed, the username on the remote device

Procedure

	Command or Action	Purpose
Step 1	switch# telnet {ip address | host-name} [port-number] [vrf vrf-name]	Creates an IP Telnet session to the specified destination. The keywords and arguments are as follows: 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.

switch# telnet 10.10.1.1

Clearing Telnet Sessions

Before You Begin

Before beginning this procedure, you must be logged in to the CLI in EXEC mode.

Procedure

	Command or Action	Purpose
Step 1	switch# show users	Displays user session information.
Step 2	switch# clear line vty-line	Clears a user Telnet session.
Step 3	switch# show users	(Optional) Displays user session information.

switch# show users
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)*
switch# clear line 1
switch# show users
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)*
switch# 

Verifying the Telnet Configuration

Use one of the following commands to verify the configuration.

Command	Purpose
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.

switch# show running-config security all
version 4.0(1)
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+V0cm7CCLUkBh+BvZRmpmOVTmU/5awfVhVxMKXMiPOPBc+A6/n3FVroyRwupMki6mW
oM6UwaGID5gsVPqFjFNSgMWtbhjo97XVKhgjFW+wOVt8QoAcrEtnwEfsnQk1EIr/0XIP1mqTsrqTsmjZ2vLk+fFzTGYAxMvYZI+BrN47aoH2ywS7CpnODjCDXJuDYSPbc3PA8t0ghU/60m9R+s6AZPuljVQbGfxPrahEu4GVc6sMJNU1
JxmqDJkodhMArObB4Umzj7E3Rdby/ZWx/clTYiXQR1X1VfhQ==
telnet server enable

banner motd # User Access Verification #

ssh key rsa 1024 force
no ssh key dsa force
ssh server enable

Feature History for Telnet

This table only includes updates for those releases that have resulted in additions to the feature.

Feature Name		Feature Information
Telnet	4.0(4)SV1(1)	This feature was introduced.