Nagios Support Forum

This is the client machine :

[email protected]:~# /usr/local/nagios/libexec/check_nrpe -H localhost -n
CHECK_NRPE: Received 0 bytes from daemon. Check the remote server logs for error messages.

root@ip-0-0-0-0:~# apt-get install libssl-dev
Reading package lists... Done
Building dependency tree
Reading state information... Done
libssl-dev is already the newest version.
The following packages were automatically installed and are no longer required:
libgudev-1.0-0 gir1.2-gudev-1.0 python-twisted-names
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

Nagios:

root@nagios:~# /usr/local/nagios/libexec/check_nrpe -H localhost -n
CHECK_NRPE: Received 0 bytes from daemon. Check the remote server logs for error messages.

root@nagios:~# apt-get install libssl-dev
Reading package lists... Done
Building dependency tree
Reading state information... Done
libssl-dev is already the newest version.
The following packages were automatically installed and are no longer required:
libgudev-1.0-0 gir1.2-gudev-1.0 python-twisted-names
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

OK - on the client machine, what is the output for this file? cat /etc/xinetd.d/nrpe

root@ip-xxx-xx-xx-xxx:~# cat /etc/xinetd.d/nrpe
# default: on
# description: NRPE (Nagios Remote Plugin Executor)
service nrpe
{
flags = REUSE
socket_type = stream
port = 5666
wait = no
user = nagios
group = nagios
server = /usr/local/nagios/bin/nrpe
server_args = -c /usr/local/nagios/etc/nrpe.cfg --inetd
log_on_failure += USERID
disable = no
only_from = 127.0.0.1 0.0.0.0 => nagios IP address

From your output, there should be one more line that has }
Is this just a copy and paste error? For example mine is:

# default: on
# description: NRPE (Nagios Remote Plugin Executor)
service nrpe
{
flags = REUSE
socket_type = stream
port = 5666
wait = no
user = nagios
group = nagios
server = /usr/local/nagios/bin/nrpe
server_args = -c /usr/local/nagios/etc/nrpe.cfg --inetd
log_on_failure += USERID
disable = no
only_from = 127.0.0.1 10.25.0.0/16
}

Yes -- sorry about that

root@ip-xx-xx-xx-xxx:~# cat /etc/xinetd.d/nrpe
# default: on
# description: NRPE (Nagios Remote Plugin Executor)
service nrpe
{
flags = REUSE
socket_type = stream
port = 5666
wait = no
user = nagios
group = nagios
server = /usr/local/nagios/bin/nrpe
server_args = -c /usr/local/nagios/etc/nrpe.cfg --inetd
log_on_failure += USERID
disable = no
only_from = 127.0.0.1 xx.xx.xxx.xx
}

On the client machine, what is the result of this? Also just saw this - above I had mentioned installing openssl-dev (it might be openssl-devel), and it looks like you tried to install libssl-dev. Can you try installing openssl-dev and post the output?

Here is the output

root@ip-xxx-xx-xx-xxx:~# netstat -anp|grep '5666'
tcp 0 0 0.0.0.0:5666 0.0.0.0:* LISTEN 5155/nrpe

Install it on both the client and the nagios machine?

Yes, you will need SSL on both machines.

I thought that libssl-dev was the ubuntu equivalent?

I don't believe so. What is the result if you try to apt-get install openssl-dev or openssl-devel?