OpenSSH 8.0 - 8.2 ClientAlive issue

Mervyn McMurray (mmcmurra) mmcmurra at
Wed Jun 10 09:45:51 AEST 2020


I have recently upgraded from OpenSSH 7.5 to OpenSSH 8.0 (I know its old, but I have complications in a cross compiled environment).

After the upgrade I have noticed the Client Alive mechanism has stopped working. I operate in a environment where it is common for the TCP link between
client and server to get dropped after a period of inactivity, due to firewall configuration.

The issue seems to be the patch created for

I have undone the patch in my OpenSSH 8.0 and ClientAlive functionality is restored to a working state.

I have tested the scenario in #2757 and it seems to work as expected on my patched OpenSSH 8.0.
I get rekey events approximately every 45 seconds and no client alive messages. SSH session remains forever.
This is the expected result from the original submitter

I suggest the original bug was possibly a confusion with "ClientAliveCountMax=0” which has been fixed recently.

I have included my revert patch. Is there anything else I need to do in order to get this fixed for OpenSSH 8.3?



More information about the openssh-unix-dev mailing list