Cisco IOS Cookbook, 2nd Edition

Locking Configuration Access

Problem

You want to prevent multiple concurrent users from making configuration changes at the same time.

Solution

To automatically prevent other users from making configuration changes at the same time as you, use the following command:

Router1#configure terminal 
Enter configuration commands, one per line.  End with CNTL/Z.
Router1(config)#configuration mode exclusive auto
Router1(config)#end
Router1#

To enable the ability to lock the configuration file, on an as-needed basis, use the following command:

Router1#configure terminal 
Enter configuration commands, one per line.  End with CNTL/Z.
Router1(config)#configuration mode exclusive manual 
Router1(config)#end                                 
Router1#

Tip

This feature was introduced in IOS Version 12.3(14)T.

Discussion

By default, the router running IOS software allows multiple concurrent users to change the running configuration files at once. In some operating environments, preventing multiple concurrent users from making changes is beneficial. Being able to prevent two users attempting to modify the same portion of the configuration file is desired. By enabling this feature, you temporarily prevent multiple users from modifying the router configuration at the same time.

Essentially, this feature allows only a single user to enter the configuration mode at a time. All other users on the router are effectively locked out of the configuration mode until the first user exits it. As we’ve seen in our examples, this feature runs in two modes, auto ...