Nagios Support Forum

Hello,

We are having issues monitoring some of the nodes in our environment. We are repeatedly seeing this error message "CHECK_NRPE: Socket timeout after 60 seconds."

We have tried some of the troubleshooting suggestions we see online to no avail. We did find out though that when we do run nmap from the nagios server against some of these nodes, port 5666 comes up as "filtered" even after disabling firewalld. We are running Red Hat 7.


Thanks.

Is iptables running as well by chance? Do you have some device sitting in the middle that may be messing with your traffic?

Iptables has been disabled. And no, there are no devices sitting in the middle that may be hindering traffic.

Thanks.

Can you telnet to port 5666?

No we can't also telnet,
It will read "Trying....ip, and then the connection will time out.

Something is filtering traffic between point A and point B. I would double check your firewall on the client.

We disabled firewall service on the client and port 5666 shows as open:

Starting Nmap 6.40 ( http://nmap.org ) at 2016-02-22 16:47 UTC
Nmap scan report for 192.168.5.2
Host is up (0.000013s latency).
Not shown: 997 closed ports
PORT STATE SERVICE
22/tcp open ssh
5666/tcp open nrpe
9200/tcp open wap-wsp

And on the Nagios server we disabled firewall service but the client port is still showing as filtered:

Starting Nmap 6.47 ( http://nmap.org ) at 2016-02-22 16:52 UTC
Nmap scan report for 192.168.5.2
Host is up (0.00078s latency).
PORT STATE SERVICE
5666/tcp filtered nrpe

Any suggestions on how to troubleshoot this?

You specified Red Hat 7, but more specifically, is this an AWS server by any chance?

Reason I ask is the nmap out put of "5666/tcp filtered nrpe" means there is a FW (or an IPS device?) somewhere and AWS may be to blame - even if you manually disabled iptables, etc on the Nagios server.

Thanks so much guys,it's up and running now...There was no firewall rule created in our vcloud for nagios. Port 5666 is now opened for nagios.

Thanks for the update and glad to hear its up and running. I'll lock this thread now and feel free to open another should you require assistance with anything else.