Console Port, Telnet, SSH Handling, and Reset

This chapter contains the following sections:

Restrictions and Notes for Console Port, Telnet, and SSH

  • Configuring the diagnostic and wait banners is optional, but recommended. The banners are especially useful as indicators to users about the status of their Telnet or SSH attempts.

Console Port Overview

The console port on the router is an EIA/TIA-232 asynchronous, serial connection with no flow control and an RJ-45 connector. The console port is used to access the router and is located on the front panel of the Route Processor.

For information on accessing the router using the console port, see Using Cisco IOS XE Software.

Console Port Handling Overview

If you are using the console port to access the router, you are automatically directed to the Cisco IOS command-line interface (CLI).

If you are trying to access the router through the console port and send a break signal (by entering Ctrl-C or Ctrl-Shift-6, or by entering the send break command at the Telnet prompt) before connecting to the CLI, you are directed to a diagnostic mode if the non-RPIOS subpackages are accessible. These settings can be changed by configuring a transport map for the console port and applying that transport map to the console interface.

Reset Overview

The Reset button present in Cisco 1100 Series ISRs is enabled for its functionality. This feature helps in the quick recovery of desktop routers. Use this feature to recover your Cisco 1100 Series ISR that is hung or stuck. Press the Reset button and boot the preconfigured “golden.bin” image and “golden.cfg” configuration.

The Reset button can be actuated only during the hardware initialization stage, after power-on, or at the reload command. The Reset button can not be used once the router gets into the Rommon mode or the IOS mode.


Note
Configure a fallback image with the name "golden.bin" (bootflash:); and a fallback configuration with the name "golden.cfg" (bootflash: or nvram:).

Configuring a Console Port Transport Map

This task describes how to configure a transport map for a console port interface on the router.

Procedure

  Command or Action Purpose
Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

transport-map type console transport-map-name

Example:


Router(config)# transport-map type console consolehandler

Creates and names a transport map for handling console connections, and enters transport map configuration mode.

Step 4

connection wait [allow [interruptible] | none [disconnect]]

Example:


Router(config-tmap)# connection wait none

Specifies how a console connection will be handled using this transport map.

  • allow interruptible—The console connection waits for a Cisco IOS VTY line to become available, and also allows users to enter diagnostic mode by interrupting a console connection that is waiting for a Cisco IOS VTY line to become available. This is the default setting.

    Note 
    Users can interrupt a waiting connection by entering Ctrl-C or Ctrl-Shift-6.

  • none—The console connection immediately enters diagnostic mode.

Step 5

(Optional) banner [diagnostic | wait] banner-message

Example:


Router(config-tmap)# banner diagnostic X
Enter TEXT message. End with the character 'X'.
--Welcome to Diagnostic Mode--
X
Router(config-tmap)#

(Optional) Creates a banner message that will be seen by users entering diagnostic mode or waiting for the Cisco IOS VTY line because of the console transport map configuration.

  • diagnostic—Creates a banner message seen by users directed to diagnostic mode because of the console transport map configuration.

    Note 
    Users can interrupt a waiting connection by entering Ctrl-C or Ctrl-Shift-6.

  • wait—Creates a banner message seen by users waiting for Cisco IOS VTY to become available.

  • banner-message—Banner message, which begins and ends with the same delimiting character.

Step 6

exit

Example:


Router(config-tmap)# exit

Exits transport map configuration mode to re-enter global configuration mode.

Step 7

transport type console console-line-number input transport-map-name

Example:


Router(config)# transport type console 0 input consolehandler

Applies the settings defined in the transport map to the console interface.

The transport-map-name for this command must match the transport-map-name defined in the transport-map type console command.

Examples

The following example shows how to create a transport map to set console port access policies and attach to console port 0: 

Router(config)# transport-map type console consolehandler
Router(config-tmap)# connection wait allow interruptible
Router(config-tmap)# banner diagnostic X
Enter TEXT message. End with the character 'X'.
--Welcome to diagnostic mode--
X
Router(config-tmap)# banner wait X
Enter TEXT message. End with the character 'X'.
Waiting for IOS vty line
X
Router(config-tmap)# exit
Router(config)# transport type console 0 input consolehandler

Viewing Console Port, SSH, and Telnet Handling Configurations

Use the following commands to view console port, SSH, and Telnet handling configurations:

  • show transport-map

  • show platform software configuration access policy

Use the show transport-map command to view transport map configurations.

show transport-map [all | name transport-map-name | type [console ]]

This command can be used either in user EXEC mode or privileged EXEC mode.

Example

The following example shows transport maps that are configured on the router: console port (consolehandler): 

Router# show transport-map allTransport Map:
Name: consolehandler Type: Console Transport

Connection:
Wait option: Wait Allow Interruptable Wait banner:

Waiting for the IOS CLI bshell banner:
Welcome to Diagnostic Mode


 
Router# show transport-map type consoleTransport Map:
Name: consolehandler
 

REVIEW DRAFT - CISCO CONFIDENTIAL

Type: Console Transport

Connection:
Wait option: Wait Allow Interruptable Wait banner:

Waiting for the IOS CLI Bshell banner:
Welcome to Diagnostic Mode

 
 
Router# show transport-map type persistent sshTransport Map:
Name: consolehandler Type: Console Transport

Connection:
Wait option: Wait Allow Interruptable Wait banner:

Waiting for the IOS CLI Bshell banner:
Welcome to Diagnostic Mode

Use the show platform software configuration access policy command to view the current configurations for handling the incoming console port, SSH, and Telnet connections. The output of this command provides the current wait policy for each type of connection (Telnet, SSH, and console), as well as information on the currently configured banners.

Unlike the show transport-map command, the show platform software configuration access policy command is available in diagnostic mode so that it can be entered in scenarios where you need transport map configuration information, but cannot access the Cisco IOS CLI.

Example

The following example shows the show platform software configuration access policy command. 

Router# show platform software configuration access policyThe current access-policies

Method : telnet
Rule : wait with interrupt Shell banner:
Welcome to Diagnostic Mode

Wait banner :
Waiting for IOS Process

Method : ssh Rule : wait Shell banner: Wait banner :

Method : console
Rule : wait with interrupt Shell banner:
Wait banner :

Configuring Console Port for Modem Connection

Cisco 1100 Series router supports connecting a modem to the router console port for EXEC dial in connectivity. When a modem is connected to the console port, a remote user can dial in to the router and configure it. To configure a modem on the console port, perform these steps:

Procedure

Step 1

Connect the RJ-45 end of the adapter cable to the console port on the router.

Step 2

Use the show line command to determine the async interface of the console port: 

Router# show  line 

 Router#show line
Tty Line Typ Tx/Rx A Modem Roty AccO AccI Uses Noise Overruns Int
* 0 0 CTY - - - - - 0 0 0/0 -
866 866 VTY - - - - - 0 0 0/0 -
867 867 VTY - - - - - 0 0 0/0 -
868 868 VTY - - - - - 0 0 0/0 -
869 869 VTY - - - - - 0 0 0/0 -
870 870 VTY - - - - - 0 0 0/0 -
Step 3

Use the following commands to configure the router console line:: 

Router(config)# line con 0 
   
Router(config-line)#modem inOut 
Router(config-line)#modem autoconfigure type usr_sportster
Router(config-line)#speed 115200  [Speed to be set according to the modem manual]
Router(config-line)#stopbits 1 [Stopbits to be set according to the modem manual]
Router(config-line)#transport input all 
Router(config-line)#flowcontrol hardware [flowcontrol to be set according to the modem manual]
Router(config-line)#password cisco
Router(config-line)#login
Router(config-line)#end
Router(config)#enable password lab
Step 4

Use the reverse telnet method on the modem to verify the modem connectivity and configuration string: 

Router(config)#int loopback 0
Router(config-if)#ip add 1.1.1.1 255.255.255.0 
Router(config-if)#end
Router#telnet 1.1.1.1 2001
Trying 1.1.1.1, 2001 ... Open

User Access Verification

Password: <enter the password given under line configuration>

at    <<<=== Modem command
OK  <<<=== This OK indicates that the modem is connected successully to the console port.
Step 5

Use an analog phone to verify that the phone line is active and functions properly. Then, connect the analog phone line to the modem.

Step 6

Initialize an EXEC modem call to the router from another device (PC) to test the modem connection.

Step 7

When the connection is established, the dial in client is prompted for a password. Enter the correct password.

Note: This password should match the one that is configured on the console port line.