`stunnel -socketsĀ“ should show the available socket options and their default values.
For the box I'm writing this mail from, the default for TCP_KEEPIDLE is 7200 and for TCP_KEEPINTVL 75 (both in seconds). You'll have to be quite patient if you want to watch keepalive packets in wireshark without tweaking the defaults ...
HTH,
Ludolf
You hit the nail on the head. I set the parameters to something more reasonable and I now see the keepalive packets. Thank you for your speedy response.
Dave