Docker swarm TCP client service goes to SYN_SENT after TCP listener service restarts and changes IP

Open Source Projects Swarm
1

I have a ZeroMQ based logging service, which listens on port 20000 for connections from other services(clients).
The whole setup works fine when the clients connect by tcp://logger_svc:20000, but if the logger_svc restarts and gets another IP, the established connections from all clients go to this state:

TCP    192.168.5.44:49349     192.168.5.37:20000    SYN_SENT
TCP    192.168.5.44:49350     192.168.5.37:20000    SYN_SENT
TCP    192.168.5.44:49351     192.168.5.37:20000    SYN_SENT

And they remain so indefinetelly.

I tried ipconfig /flushdns but it didn’t help. nslookup logger_svc inside client container returns the new IP.
Nothing helps short of restarting the client services.

The logger_svc is in its own stack/compose file, but it shares the same overlay network with the clients, and has full connectivity until restarted.

2

The issue in this case was with Windows Server DNS cache service, this helped:

New-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters' -Name MaxCacheTtl -Value 0 -Type DWord
New-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters' -Name MaxNegativeCacheTtl -Value 0 -Type DWord