Can't get check_nrpe to work on Windows host

[craigtho]

Hi all,

So I configured my own Nagios core server (version 4.4.3) on Ubuntu 18.04 LTS VM. I have set it up to monitor most of the hosts on my infra, both Linux & Windows. I'm still very new to installing and configuring Nagios so some things are probably not up to scratch on my end.

Nagios server (Ubuntu 18.04) - 192.168.80.44
Host to monitor (Windows 10) - 192.168.60.41

On my web interface, I can see that my machine I'm monitoring has picked up all the defined check_nt services I have listed in my .cfg directory, so I know that checks are being carried out successfully (at least with check_nt):

https://imgur.com/a/CG1uE6h

The hosts .cfg file is as follows:

my-pc.cfg

my-pc.cfg

(3.99 KiB) Downloaded 193 times

When I try to run

Code: Select all

/usr/local/nagios/libexec/check_nrpe -H 192.168.60.41 -p 5666

, I get the following error:

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root@glamon02:/usr/local/nagios/libexec# ./check_nrpe -H 192.168.60.41 -p 5666
CHECK_NRPE STATE CRITICAL: Socket timeout after 10 seconds.

Similarly:

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root@glamon2:/usr/local/nagios/libexec# sudo ./check_nrpe -H 192.168.60.41 -p 5666 -t 30
CHECK_NRPE STATE CRITICAL: Socket timeout after 30 seconds.
root@glamon2:/usr/local/nagios/libexec# telnet 192.168.60.41 5666
Trying 192.168.60.41...
Connected to 192.168.60.41.
Escape character is '^]'.

My Windows NSCLIENT++ file is as follows (after some changes):

nsclient.ini

nsclient.ini

(7.13 KiB) Downloaded 214 times

What am I missing? I know its got to be something simple and I need check_nrpe for part of the monitoring I need on this host.

[scottwilkerson]

On your Windows server run the following from the cmd prompt:

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cd "C:\Program Files\NSClient++"
nscp settings --activate-module NRPEServer --add-defaults
nscp settings --path /settings/NRPE/server --key "allow arguments" --set true
nscp settings --path /settings/NRPE/server --key "allow nasty characters" --set true
nscp settings --path /settings/NRPE/server --key insecure --set true
nscp settings --path /settings/NRPE/server --key "verify mode" --set none
nscp settings --activate-module CheckExternalScripts --add-defaults
nscp settings --path "/settings/external scripts" --key "allow arguments" --set true
nscp settings --path "/settings/external scripts" --key "allow nasty characters" --set true

the restart nsclient++

[craigtho]

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C:\Program Files\NSClient++>nscp settings --path /settings/NRPE/server --key "allow arguments" --set true

C:\Program Files\NSClient++>nscp settings --path /settings/NRPE/server --key "allow nasty characters" --set true

C:\Program Files\NSClient++>nscp settings --path /settings/NRPE/server --key insecure --set true

C:\Program Files\NSClient++>nscp settings --path /settings/NRPE/server --key "verify mode" --set none

C:\Program Files\NSClient++>nscp settings --activate-module CheckExternalScripts --add-defaults
Adding default values

C:\Program Files\NSClient++>nscp settings --path "/settings/external scripts" --key "allow arguments" --set true

C:\Program Files\NSClient++>nscp settings --path "/settings/external scripts" --key "allow nasty characters" --set true

C:\Program Files\NSClient++>net stop nscp
The NSClient++ (x64) service is stopping..
The NSClient++ (x64) service was stopped successfully.


C:\Program Files\NSClient++>netstart nscp
'netstart' is not recognized as an internal or external command,
operable program or batch file.

C:\Program Files\NSClient++>net start nscp
The NSClient++ (x64) service is starting.
The NSClient++ (x64) service was started successfully.

Followed by running a a few commands for experiments sake:

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root@glamon2:/usr/local/nagios/libexec# ./check_nrpe -H 192.168.60.41
CHECK_NRPE STATE CRITICAL: Socket timeout after 10 seconds.
root@glamon2:/usr/local/nagios/libexec# ./check_nrpe -H 192.168.60.41 -p 5666
CHECK_NRPE STATE CRITICAL: Socket timeout after 10 seconds.
root@glamon2:/usr/local/nagios/libexec# ./check_nrpe -H 192.168.60.41 -p 12489
CHECK_NRPE: (ssl_err != 5) Error - Could not complete SSL handshake with 192.168.60.41: 1
root@glamon2:/usr/local/nagios/libexec# ./check_nrpe -H 192.168.60.41 -t 30
CHECK_NRPE STATE CRITICAL: Socket timeout after 30 seconds.
root@glamon2:/usr/local/nagios/libexec# ./check_nrpe -H 192.168.60.41 -p 5666 -t 30
CHECK_NRPE STATE CRITICAL: Socket timeout after 30 seconds.
root@glamon2:/usr/local/nagios/libexec#

New nsclient.ini attached below:

nsclient.ini

nsclient.ini (2)

(13.43 KiB) Downloaded 165 times

[scottwilkerson]

Are you sure port 5666 is open on the Windows and any network firewalls?

[craigtho]

Yes, as seen in my original post, I ran a telnet to the Windows machine on port 5666 which connected successfully.

I checked with nmap just to be safe and it's definitely open.

Furthermore, turning off the firewall on Windows still provides a timeout error.

[scottwilkerson]

Can you attach the nsclient.log from the machine in question.

Thanks!

[craigtho]

I think this is the file you are looking for:

nsclient.log

nsclient.log

(11.96 KiB) Downloaded 218 times

[scottwilkerson]

Can I have you try adding

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ssl options = no-sslv2,no-sslv3

under the section

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[/settings/NRPE/server]

to the nsclient.ini and then restart nsclient++

Also, what version of NSClient++ are you using?

How about check_nrpe on the Nagios server?

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/usr/local/nagios/libexec/check_nrpe -h|head -5

[craigtho]

Changes were made to the nsclient.ini file as seen in here:

nsclient.ini

nsclient.ini

(13.5 KiB) Downloaded 321 times

Then on Nagios Server (running an nmap just for demonstration purposes):

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root@glamon2:/usr/local/nagios/libexec# ./check_nrpe -H 192.168.60.41 -p 5666 -t 30
CHECK_NRPE STATE CRITICAL: Socket timeout after 30 seconds.
root@glamon2:/usr/local/nagios/libexec# nmap -Pn 192.168.60.41 -p 5666

Starting Nmap 7.60 ( https://nmap.org ) at 2019-09-16 20:33 UTC
Nmap scan report for my-pc.my.domain (192.168.60.41)
Host is up (0.00056s latency).

PORT     STATE SERVICE
5666/tcp open  nrpe

Nmap done: 1 IP address (1 host up) scanned in 0.33 seconds

root@glamon2:/usr/local/nagios/libexec# nmap -Pn 192.168.60.41 -p 12489

Starting Nmap 7.60 ( https://nmap.org ) at 2019-09-16 20:33 UTC
Nmap scan report for my-pc.my.domain (192.168.60.41)
Host is up (0.00053s latency).

PORT      STATE SERVICE
12489/tcp open  unknown

Nmap done: 1 IP address (1 host up) scanned in 0.32 seconds

root@glamon2:/usr/local/nagios/libexec# ./check_nrpe -h | head -5
NRPE Plugin for Nagios
Version: 3.2.1

Copyright (c) 2009-2017 Nagios Enterprises
              1999-2008 Ethan Galstad ([email protected])

Still unsure as why its timing out. I had been reading the forums for hours on this to see if anyone had the same issue with NRPE on Windows

[scottwilkerson]

Can you make a backup of your nsclient.ini and try this one that I know is working on my system

You have a few extraneous settings in yours (like blank certificate and custom allowed ciphers) but this should work