Cisco Nexus 1000V Security Configuration Guide, Release 4.2(1)SV1(4a)
Configuring Telnet
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Configuring Telnet

Table Of Contents

Configuring Telnet

Information About the Telnet Server

Prerequisites for Telnet

Guidelines and Limitations

Default Setting

Configuring Telnet

Enabling the Telnet Server

Starting an IP Telnet Session to a Remote Device

Clearing Telnet Sessions  

Verifying the Telnet Configuration

Additional References

Related Documents

Standards

Feature History for Telnet


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.

Parameters
Default

Telnet server

Enabled.


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

 
Command
Purpose

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

 
Command
Purpose

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

 
Command
Purpose

Step 1 

show users


Example:

n1000v# show users

Displays user session information.

Step 2 

clear line vty-line


Example:

n1000v# clear line 1

Clears a user Telnet session.

Step 3 

show users


Example:

n1000v# show users

Displays user session information.

Example:

n1000v# 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)*
n1000v# clear line 1
n1000v# 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)*
n1000v# 

Verifying the Telnet Configuration

To display the Telnet configuration information, use one of the following commands:

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.


Example:

n1000v# 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+V0cm7CCLU
kBh+BvZRmpmOVTmU/5awfVhVxMKXMiPOPBc+A6/n3FVroyRwupMki6mW
oM6UwaGID5gsVPqFjFNSgMWtbhjo97XVKhgjFW+wOVt8QoAcrEtnwEfsnQk1EIr/0XIP1mqTsrqTsmjZ2vLk+fFzTG
YAxMvYZI+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

Additional References

For additional information related to implementing Telnet, see the following sections:

Related Documents

Standards

Related Documents

Related Topic
Document Title

SSH

Chapter 7, "Configuring SSH"

CLI

Cisco Nexus 1000V Getting Started Guide, Release 4.2(1)SV1(4a)


Standards

Standards
Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.


Feature History for Telnet

This section provides the Telnet release history.

Feature Name
Releases
Feature Information

Telnet

4.0(4)SV1(1)

This feature was introduced.