nrpe: Host is not allowed to talk to us

Solution 1:

Had the same entry in my syslog. Editing /etc/nagios/nrpe.cfg and enter missing IP will fixed it at all.

allowed_hosts=1.2.3.4/24,127.0.0.1

After editing you have to restart or even reload nrpe deamon.

/etc/init.d/nagios-nrpe-server reload

Check if it is all fine with your configuration. Syslog should have an entry like this:

Allowing connections from: 1.2.3.4/24,127.0.0.1

I advise you not to add user nagios to sudoers because of security issues.

Solution 2:

A lot of how-to's here and there ask you to allow your monitoring server IP like this in your host's /etc/nagios/nrpe.cfg :

allowed_hosts=127.0.0.1, 1.2.3.4

On some distribs (Ubuntu 14.04 LTS for instance), it's working. On other (Ubuntu 12.04 LTS - tested on Microsoft Azure in my case), it does not.

Just remove the space before second IP :

allowed_hosts=127.0.0.1,1.2.3.4

Then, of course, restart your host's nrpe service :

$ service nagios-nrpe-server restart

Solution 3:

I found the solution, but the error message is totally misleading. The user nagios has to be in the suders...

/etc/sudoers:

nagios  ALL=(ALL) NOPASSWD: /usr/lib/nagios/plugins/