RELOAD COMMAND

One of the classic mistakes (I know because I have done it myself a number of times) is to incorrectly update an access-list on an interface when you are connected to the device remotely. And suddenly, the Telnet connection is dropped to the router because of a forgotten list entry that would permit your incoming connection.

There is another way. When you are doing something tricky, you can use the following feature of the reload command, which causes the router to reboot in a certain number of minutes. For example, let's tell the router to reboot in three minutes.

MyRouter#reload in 3
    Reload scheduled in 3 minutes
Proceed with reload? [confirm]y

Now, we have three minutes to do what we need to do. Let's say we are applying an access-list to serial0.

MyRouter#config terminal
Enter configuration commands, one per line.  End with CNTL/Z.
MyRouter(config)#interface serial0
MyRouter(config-if)#ip access-group 110 in
MyRouter(config-if)#^Z
MyRouter#

We made the change and everything still works. (Well, at least our connection wasn't dropped.) Now all we have to do cancel the impending reload with the following command:

MyRouter#reload cancel