[stunnel-users] keepalive and stunnel

Tue Jul 23 19:30:08 CEST 2013

I am attempting to use stunnel to provide secure telnet access to a 
server on my system.  As it is possible that a user may be idle for long 
period I have attempted to enable keepalive with stunnel.  My stunnel 
conf files contain:

socket = l:SO_KEEPALIVE=1
socket = r:SO_KEEPALIVE=1

on both the server and client side.  But wireshark shows no keepalive 
packets being exchanged.  I am using socat to provide a service on the 
LAN and connections using socat do show keepalive packets.  But to get 
this working with socat I had to use the following:

socat -d -d -L/var/lock/Port$PORT - 
TCP:127.0.0.1:$PORT,keepalive,keepcnt=10,keepidle=3,keepintvl=1

I had originally tried it with only the keepalive option, but it took 
adding the other three options for it to work.  Perhaps this is 
particular to my linux mint 13 maya x64 system and keepalive works by 
itself on windows?  Are the other three options supported in stunnel?

Dave