A free and open source CLI program that keeps your connections alive
Version: 1.2lifekeeper is a completely trivial program that prints an ASCII NUL character every 30 seconds.
Operating System: Mac OS X
lifekeeper has no visual effect, but if someone is actually watching the connection for activity it will see some.
People using remote connections through firewalls might find it useful, as often masquerading firewalls are configured so to shut down connections that appear not to be active for some time.