Nagios Support Forum

Hello,


I am getting a CHECK_NRPE: Error -Could not complete SSL handshake on a client running RHEL5. I have checked and double-checked all the configuration settings in /etc/xinetd.d/nrpe to make sure I have included the server and the localhost in the "only_from" line. Ran "check_nrpe -H avalon" from both the server and the localhost and it still comes up with the error. I have also stopped iptables for troubleshooting purposes. I ran NMAP on port 5666 from the server to the client and the port is open. I don't know what else to check. Any help from you guys will be greatly appreciated. Thank you.


V/R,


Christopher Gutierrez

+ Nmap may show :5566 open, but could you confirm NRPE is running on the client machine?
netstat -anp|grep :5666

+ Could it be that NRPE was not compiled with ssl enabled? - refer to page 4 of https://assets.nagios.com/downloads/nag ... utions.pdf

+ How was NRPE installed? From source, repo, or from the XI agent download?

Here is what I got when doing a "netstat -anp | grep :5666":

tcp 0 0.0.0.0:5666 0.0.0.0:* LISTEN 15613/xinetd
tcp 0 <client ip>:5666 <server ip>:43190 TIME_WAIT -

I have re-ran the installation of NRPE with SSL enabled, and it still does not work.

I installed NRPE using the .tar.gz file I downloaded from your repo since the network I am using it one is disconnected from the internet.

Is your Nagios server listed in the only_from field of /etc/xinetd.d/nrpe on the client machine?
If not, you need to add it and then restart xinetd

Yes, my Nagios server is listed in the only_from field. I don't know what else could be wrong.

you mentioned you ran the following from both server Are we sure they can resolve "avalon"?

Can you run it using the IP address?

Yes, it also resolves with IP as well.

Can you please run these commands on the NRPE Client and show us the output:

Here is the output:

[root@avalon ~]# ps -C xinetd
PID TTY TIME CMD
23025 ? 00:00:00 xinetd

[root@avalon ~]# ps -C nrpe
PID TTY TIME CMD

I have checked and double-checked all the configuration settings in /etc/xinetd.d/nrpe to make sure I have included the server and the localhost in the "only_from" line.

Are these two IP addresses separated by a space or a comma? You haven't really showed us the output of "cat /etc/xinetd.d/nrpe|grep only_from" as requested by scottwilkerson, so it's hard to say what you have on the "only_from" line.

Have you restarted xinetd after adding the Nagios XI server's ip to to "/etc/xinetd.d/nrpe"?
Is SELinux disabled? Are you using tcp wrappers? Do you have anything in the hosts.allow and/or hosts.deny?

Are you performing a large number of NRPE checks in a relatively short period of time? If this is the case, you can try adding the following two lines to "/etc/xinetd.d/nrpe" file:
as described here:
https://assets.nagios.com/downloads/nag ... utions.pdf

Run the following command on the Nagios XI server, and show the output: