Cisco IOS Cookbook, 2nd Edition

Automating the Login Sequence

Problem

You want to automate the process of logging into a router, typing usernames, passwords, and so forth.

Solution

The following script automates the process of logging into the router using a scripting language called Expect. Expect is a powerful scripting language that provides automation of interactive sessions (see Appendix A for more details). The script takes a router name or IP address as a command line argument. It then performs an automated login sequence before returning the session back to you for a normal interactive session.

Here is the sample output:

Freebsd% tel Router1
spawn telnet Router1
Trying 172.25.1.5...
Connected to Router1.
Escape character is '^]'.


User Access Verification

Username: ijbrown
Password: 

Router1>
Router1 - vty login ok
enable
Password: 
Router1#
Router1 - enable login ok

Router1#term mon
Router1#

The Expect code follows in Example 3-3.

Example 3-3. tel

#!/usr/local/bin/expect # # tel -- a script to perform automated login onto a Cisco # router using either a hostname or IP address. # # # Set behaviour set userid ijbrown set vtypasswd oreilly set enablepwd cookbook # # set timeout 10 set rtr [lindex $argv 0] spawn telnet $rtr expect { {Username} { send "$userid\r" expect { {*Password*} { send "$vtypasswd\r" } } } {telnet>} { send_user "$rtr - telnet failed\n" exit } {Password} { send "$vtypasswd\r" } } expect { {Password} { send_user "\n$rtr - vty login failed\n" exit } {Username} { send_user "\n$rtr - vty login failed\n" ...