I'm building a test network for monitoring, so far I have a Ubuntu 9.10 server running Nagios 3.2.1, I followed the install documents from the Nagios site, they worked 100% for Ubuntu but had problems installing the agent on another Ubuntu server.

Below is the steps how I'm doing the install.

1) sudo -s

2) /usr/sbin/useradd nagios

3) passwd nagios

4) enter in standard password

5) tar xzf nagios-plugins-1.4.14.tar.gz

6) cd nagios-plugins-1.4.14

7) ./configure

8) make

9) make install

10) chown nagios.nagios /usr/local/nagios

11) chown -R nagios.nagios /usr/local/nagios/libexec

12) apt-get install xinetd

13) tar xzf nrpe-2.12.tar.gz

14) cd nrpe-2.14

15) ./configure (had some problems were it would only work if I added --disable-ssl)

16) make all

17) make install-plugin

18) make install-daemon

19) make install-daemon-config

20) make install-xinetd

21) vi /etc/xinetd.d/nrpe

22) edit "only_from = xxx.xxx.xxx.xxx (Nagios server)"

23) vi /etc/services

24) add "nrpe 5666/tcp # NRPE

25) service xinetd restart

26) netstat -at | grep nrpe

27) result - tcp 0 0 *:nrpe *:* LISTEN

28) /usr/local/nagios/libexec/check_nrpe -H localhost

29) result - "CHECK_NRPE: Received 0 bytes from daemon. Check the remote server logs for an error message."

I searched the files and Nagios docs but think the problem is something do due with SSL. I'm not sure where to find this or is it possible to disable SSL? Should I just start over on the Nagios server and compile as non-SSL?

Thanks so much!

FYI- NRPE is not necessary for localhost monitoring.

I might have it incorrect. I have two servers, both running Ubuntu. Server 1 is running Nagios, as the reporting, while Server 2 is just running the agents. The problem is if the steps I did on Server 2 will work connecting to Server 1, or did I make a mistake on something else.

I'm really green so I'm sure I overlooked something.

I think you have missed the configration of nrpe.cfg file.
This file is located under /usr/local/nagios/etc/nrpe.cfg , in that
file you have to write the command checks , and the hosts to allow ,
then you have to check it with
ex : /usr/local/nagios/libexec/check_nrpe -H localhost -c current_users
// if you have the commnad to check the users currently logged already
then reply will come with no.of users logged in either with ok are warning stage , by the values mentioned in nrpe.cfg.