Nagios Support Forum

Posted: **Fri Jan 19, 2018 7:05 am**

I've exhausted all the avenues I know so I'm turning to the forum for help.

I have a server (dev-int) running NRPE.
I have 2 Nagios servers that can connect without any problem.
I have added a third Nagios server and I get this in the syslog of dev-int running NRPE.

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Jan 19 11:41:50 dev-int nrpe[18468]: CONN_CHECK_PEER: checking if host is allowed: 10.58.2.44 port 8360
Jan 19 11:41:50 dev-int nrpe[18468]: is_an_allowed_host (AF_INET): is host >10.58.2.44< an allowed host >10.58.2.44<
Jan 19 11:41:50 dev-int nrpe[18468]: refused connect from 10.58.2.44 (10.58.2.44)

I have added 10.58.2.44 to both the nrpe.cfg file, and the /etc/xinetd.d/nrpe file and restarted both services, but without success. I still get connection refused. I can obviously get to the server or I wouldn't have an entry in the syslog. There's no local firewall that I can detect. Running 'service iptables status' comes back with an unrecognised service.

So something on dev-int is refusing the connection but I haven't a clue what it could be.

Can anyone put me out of my misery please?

Posted: **Fri Jan 19, 2018 4:48 pm**

Hello, @as300182. How did you install the NRPE? Do you have a link to the tutorial you've used? When you add the IP address in /etc/xinetd.d/nrpe, you need to separate them with spaces, and when you add IP's to nagios.cfg you need to separate them with commas.
What version of check_nrpe plugin does the new Nagios server have? And what version do the old servers use? You can test that by running ./check_nrpe with no arguments:

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/usr/local/nagios/libexec/check_nrpe

Posted: **Wed Jan 24, 2018 11:49 am**

I'm running the latest version of NRPE. I think the issue was with the nrpe.cfg file. I still can't see what's wrong with the original config file, but I replaced it with the base config file that is installed when you build NRPE, and then updated it with my changes. After a restart of the service it's working a treat. I'm guessing there's a non unix character in there somewhere, but as I say, I can't see it.

I followed the old 'start from scratch with the minimum of settings' approach and it paid off. Wish I'd tried that to start with now. I wonder. Is there a Linux tool that can scan text files for dodgy characters?

Posted: **Wed Jan 24, 2018 12:05 pm**

You can open the file in "vi", type the following text, and hit "Enter":

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:set ff?

You should see:

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fileformat=unix

If you see anything else, for example "dos" instead of "unix", you could type:

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:set ff=unix

and hit "Enter". This will fix the format.

You could also use "dos2unix" program to convert the file. If you don't have it installed, run (on RHEL/CentOS):

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yum install dos2unix -y

or run (on Ubuntu/Debian):

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sudo apt-get install dos2unix

You can view the usage (help menu) by running:

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dos2unix --help

Hope this helps.

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