I find that usually, long-lived idle TCP connections get killed by stateful firewalls, of which there are often several along any given path through the Internet.
e.g. my home router has a connection timeout of 24 hours.
There's quite a number of stateful firewalls that just silently drop the connection with out sending a RST though, meaning TCP connections are idling forever, if it does not employ any tcp or application level keep-alives or timeouts.
There's quite a number of stateful firewalls that just silently drop the connection with out sending a RST though, meaning TCP connections are idling forever, if it does not employ any tcp or application level keep-alives.
e.g. my home router has a connection timeout of 24 hours.