Nagios Support Forum

Posted: **Tue Jun 18, 2013 6:46 pm**

HI,
I have just rolled out NRPE to 50+ RHEL/CentOS VMs in my environment and they are all working fine except for one of them. On this VM I get the error CHECK_NRPE: Error - Could not complete SSL handshake.

Now when I've had this in the past its an easy fix, either open-ssldevel install, the nrpe config IP address or the nrpe port missing from /etc/services, but this time it doesn't work. I noticed that on this affected VM it has 2 nics, eth0 is a local only network (no access outside the VM) and eth1 is my regular network. I think what is happening is NRPE is hitting the first localonly network and failing, because if I run check_nrpe -h localhost it works, but from my nagios server it errors with the SSL handshake.

I have tried putting the localonly IP into the /etc/xinetd.d/nrpe config as well as also # the only_from section but no joy.

Any ideas?

Andy

Posted: **Wed Jun 19, 2013 1:37 pm**

First, i want to make you aware (if you are not already) of a document for troubleshooting nrpe:
http://assets.nagios.com/downloads/nagi ... utions.pdf

On the remote host, run check_nrpe again with the -v switch (does nothing, but will force usage to be displayed).

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./check_nrpe -H localhost -v

You should see output resembling:

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NRPE Plugin for Nagios
Copyright (c) 1999-2008 Ethan Galstad ([email protected])
Version: 2.12
Last Modified: 03-10-2008
License: GPL v2 with exemptions (-l for more info)
SSL/TLS Available: Anonymous DH Mode, OpenSSL 0.9.6 or higher required

Post the results of the SSL line, fro example:

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SSL/TLS Available: Anonymous DH Mode, OpenSSL 0.9.6 or higher required

And also:

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which openssl
openssl version

Posted: **Wed Jun 19, 2013 4:13 pm**

Thanks, didn't know about that PDF.

Actually just solved the issue but not how I expected. I asked the team who used the VM if they needed a loopback NIC and they said they didn't, so I disabled it and NRPE started working OK.

FWIW the output of that command showed below, but looks like it was the first nic being the loopback which caused it.

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SSL/TLS Available: Anonymous DH Mode, OpenSSL 0.9.6 or higher required

Thanks anyway

Nagios Support Forum

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