One of the most annoying things I can think of is having multiple Cisco IOS terminal sessions open and then switching back over to one of the terminal windows only to find that the session has been disconnected. Here is how you fix that.
- First log back into the Cisco IOS session.
- line vty 0-16 (if you are not sure how many lines you have just type line vty ?)
- exec-timeout 0
- copy run start