[Serusers] Keep Alives? SO_KEEP_ALIVE? TCP Null packet?

[Jamie Yukes]

I use TCP for my SIP connections.  I have noticed other proxy servers
send TCP "null packet" keep-alives during a connection.  What is the
feasibility of doing something like this in SER?  Where would you
steer someone who would consider implementing?

In particular this would solve a firewall issue related to "inactivity
timeout".  (UAC and UAS don't support Session Timers)

Jamie Yukes