Cygwin ssh session disconnects after exactly 30 minutes

Question

Running Windows 10 Cygwin64 - latest version openssh - latest version

After opening an ssh session - Cygwin will send a reset to the remote server after exactly 30 minutes (the firewall logs show the reset arriving at 29:59 after the tcp session was established - I'm assuming there's some rounding down there [aka 29:59.800 just shows up at 29:59, etc]) every single time, without fail.

It will send this reset whether the connection is idle or not.

Any help of where to look would be greatly appreciated.

Answer 1

Cygwin released openssh 8.0p1-2 in the middle of April. (announcement)

I didn't install it until mid-June, but had similar issues to yours. My ssh sessions, active or not, never made it past 30 minutes, though sometimes the abrupt disconnects happened at 20 minutes rather than 30.

Re-running the Cygwin installer, it is (at the time of this writing) still offering a regression to openssh 7.9p1-1. Running version 7.9, the problem seems to have cleared up.

Obviously, running an out-of-date version of the application is not a long-term solution, but I'm not sure yet whether the problem is with the updated openssh or with the Cygwin-compiled version of it. I don't see any mentions of similar problems in the Cygwin mailing list archives, so there may be other triggering factors making this an infrequent problem. Hopefully the issue with the new version can be addressed before the old version becomes prohibitively outdated.