I am getting this output randomly. “CHECK_NRPE: Socket timeout after 10 seconds.” but it fixes itself automatically & the service check is green. I dont believe its a firewall issue. I also see the agent is installed & running on the remote host server.
The Icinga 2 network monitoring daemon (version: r2.13.1-1)
Platform: Debian GNU/Linux
Platform version: 9 (stretch)
Kernel version: 4.9.0-12-amd64