Morning,
I hope someone can help! 
I have a nagios server in one network (i.e. 192.168.100.0/24 for example) and our windows servers are in another network (i.e. 172.20.20.0/22 for example). The server is built on Ubuntu, and using NSClient on the windows servers.
I have ports tcp 5666 and tcp 12489 open between the nagios server and the windows servers.
The setup is working as Nagios can see all hosts and services on the windows network. Sometimes for no apparent reason we get the following error(s), which quickly goes away if left.
“Could not fetech information from server”
“Socket timeout”
I’ve tried upgrading the nsclient on the windows servers but this has not worked.
Any help would be much appreciated!!
Thanks,
Antony