Configure Telnet Password on a Router to Avoid Error Message

Introduction

This document provides a sample configuration for how to configure a Telnet password on a Cisco router, which allows IP devices access to the router. Without a Telnet password configured, you receive the Password required, but none set error message.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

This document is not restricted to specific software and hardware versions.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Conventions

Refer to Cisco Technical Tips Conventions for more information on document conventions.

Background Information

If you try to telnet to a router that does not have a Telnet password configured, you receive this error message:

Router-1#telnet 10.3.3.1 

Trying 10.3.3.1 ... Open

Password required, but none set

[Connection to 10.3.3.1 closed by foreign host]

Configure

In this section, you are presented with the information to configure a Telnet password.

Note: Use the Command Lookup Tool (registered customers only) to obtain more information on the commands used in this section.

Configurations

This document uses the Router-2 configuration.

In order to set up the router to allow Telnet access, issue the line vty command. This command allows for the configuration of Virtual Terminal (VTY) lines for remote console access. You can configure the router to accept one or more Telnet sessions. It is strongly suggested that you configure password checking with the login and password line configuration commands. This example configures the router to accept five sessions, with the password "letmein":

Router-2(config)#line vty 0 4
Router-2(config-line)#login
% Login disabled on line 66, until 'password' is set
% Login disabled on line 67, until 'password' is set
% Login disabled on line 68, until 'password' is set
% Login disabled on line 69, until 'password' is set
% Login disabled on line 70, until 'password' is set
Router-2(config-line)#password letmein

Verify

In order to verify that the router is correctly configured for Telnet, issue the show running-config command.

Router-2#show running-config  
 Building configuration...
hostname Router-2
 .
 .
line vty 0 4
password letmein
 login
 .
 .
 ! 
end

You should now be able to telnet to the router.

Router-1#telnet
10.3.3.1 
Trying
10.3.3.1 ... Open
User
Access Verification
Password:
letmein
Router-2#

Troubleshoot

This section provides information you can use to troubleshoot your configuration.

Invalid Encrypted Password Error Message Received

When trying to configure a encrypted password in the VTY line, this error message is received:

Invalid encrypted password

The workaround is to check if the encryption service is disabled in your router. If it is disabled, then enable the encryption service. Also, in order to configure a password in the VTY line interface, it is not needed to specify any encryption method.

Related Information

• Technical Support & Documentation - Cisco Systems