We are facing these error messages in NXLog log files:

2018-12-09 23:45:16 ERROR om_tcp detected a connection error;Connection timed out 2018-12-09 23:45:16 INFO reconnecting in 2 seconds 2018-12-09 23:45:17 INFO connecting to 192.168.1.2:1468 2018-12-10 01:56:53 INFO reconnecting in 1 seconds 2018-12-10 01:56:53 ERROR om_tcp detected a connection error;Connection timed out 2018-12-10 01:56:53 INFO reconnecting in 2 seconds 2018-12-10 01:56:54 INFO connecting to 192.168.1.2:1468 2018-12-10 04:08:30 INFO reconnecting in 1 seconds 2018-12-10 04:08:30 ERROR om_tcp detected a connection error;Connection timed out 2018-12-10 04:08:30 INFO reconnecting in 2 seconds 2018-12-10 04:08:31 INFO connecting to 192.168.1.2:1468

I suspect that our firewall is blocking those connections eventually as i can't see any TCP Keep-Alive packets in tcpdump from the server where the NXLog agent is installed. On 2015-04-01 2.9.1361 changelog is this line:

All tcp based network modules are now using TCP_KEEPALIVE to detect dead peers.

Any ideas on how to fix this?