Prevents putty from becoming inactive.

Reprinted from: http://www.uberullu.com/prevent-putty-session-from-going-inactive-how-to/
Prevent putty Session from going inactive [How to]

Frequent users of putty shoshould have encounteredPutty (inactive)Problem. this happens because servers are usually configured to disconnect idle sessions after they are inactive for a special time. this has disadvantages. you can no longer monitor the jobs running in the background and the up arrow for previous commands may not work. and you have to enter the username and password again after restarting the session.

This is how you keep it alive for longer periods

1. Before saving a session, click onConnectionIn the left pane.
2. Enter a number, in place of zero, in the text box.
   EX: I use 30.
   
3. Now, go backSessionAndSaveYour session with the IP address.
   

This way, the session sends a keep-alive request to the server every 30 seconds. Hence, it stays active.