Nagios Support Forum

On the Windows system in the nsc.ini if you are running the older version of NSClient or the nsclient.ini file, you need to add the IP address of the server that is failing and restart the NSClient service.
The setting is allowed_hosts or allowed hosts depending in the NSClient version.
Let us know if this fixed it for you.

Hello.

Sorry in clumsy English.

I'm sorry. It is not told well and.
It is itemized, but writes below it.

・C can be monitored from A.
・I cannot watch C from B.
・A and B are using the same cfg file.
・In B, it is synchronized with A.
・The monitoring object except C becomes the result same as A in B.
・I want to know why only C turns out different from A in B.
・Do A and B become the same result if they change which setting?
・Where is the place that you should investigate?

I'm sorry, but will you lend the power?
Thank you in advance.

On your windows server being monitored.
C:\Program Files\NSClient++\
In the file nsc.ini or nsclient.ini

There should be:

allowed_hosts=
or
allowed hosts =

This should be a comaseparated list of allowed hosts. 192.168.33.10,10.27.34.2

It should have the IP addresses of both Nagios Servers monitoring it.

Hello.

Sorry in clumsy English.

An IP address of A and B is entered in nsc.ini.
NSClient service of C also restarted, but a phenomenon doesn't change.
nsc.ini in C is attached.

ServerA IP=192.168.21.13
ServerB IP=192.168.3.6

Could you check it?

The nsc.ini file looks correct.

Can you try the following command from both A and B Nagios servers and post back the results:

Hello.

Sorry in clumsy English.

There were no nmap commands in A and B.

Execution result by server A
/usr/local/nagios/libexec/check_nrpe -H 192.168.4.254
I (0.3.8.69 2010-05-19) seem to be doing fine...

Execution result by server B
/usr/local/nagios/libexec/check_nrpe -H 192.168.4.254
CHECK_NRPE: Socket timeout after 10 seconds.

ServerC IP=192.168.4.254

Could you check it?

You'll need to install nmap.
Then run the nmap commands.

Hello.

nmap was installed and carried out.

Execution result by server A
nmap -p 5666 192.168.4.254

Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2016-04-27 15:49 JST
Interesting ports on 192.168.4.254:
PORT STATE SERVICE
5666/tcp open unknown

Nmap finished: 1 IP address (1 host up) scanned in 0.118 seconds

Execution result by server B
nmap -p 5666 192.168.4.254

Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2016-04-27 15:45 JST
Failed to find device eth0 which was referenced in /proc/net/route
Failed to find device eth0 which was referenced in /proc/net/route
nexthost: failed to determine route to 192.168.4.254
QUITTING!

Could you check it?

P3_25 wrote:Execution result by server B
nmap -p 5666 192.168.4.254

Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2016-04-27 15:45 JST
Failed to find device eth0 which was referenced in /proc/net/route
Failed to find device eth0 which was referenced in /proc/net/route
nexthost: failed to determine route to 192.168.4.254
QUITTING!

It appears that server B has no way of getting to 192.168.4.254.

Perhaps a static route is required?

Hello.


The static route was set in neither B nor A.

Still is it necessary?

In addition, is there the place that you should doubt?

Could you check it?