sshd doesn't disconnect for 30+ minutes after the TCP connection is closed ungracefully

From: Yuri <yuri_at_FreeBSD.org>
Date: Wed, 01 Mar 2023 10:35:17 UTC
Windows system connects to FreeBSD through ssh and then this connection 
dies because of WiFi or VPN issues.

FreeBSD still has the sshd process alive for this connection for 30+ 
minutes.

TCP keepalive is enabled on the FreeBSD host:

$ sysctl net.inet.tcp.always_keepalive
net.inet.tcp.always_keepalive: 1

Shouldn't TCP keepalive kill this sshd process after 3-4 minutes because 
this connection isn't alive?


Yuri