check_nrpe : No route to host

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Re: check_nrpe : No route to host

Postby donnyforbes » Fri Jun 16, 2017 2:59 pm

So I ran the following command on my RHEL remote host sever and saw the following.

[root@huey xinetd.d]# firewalld-cmd --zone=public --list-all
-bash: firewalld-cmd: command not found
[root@huey xinetd.d]# firewall-cmd --zone=public --list-all
public (active)
target: default
icmp-block-inversion: no
interfaces: eno1
sources:
services: dhcpv6-client ssh
ports: 2301/tcp 80/tcp 9102/tcp 10033/tcp 10032/tcp 10023/tcp 10022/tcp 10030/tcp 2381/tcp 10031/tcp
protocols:
masquerade: no
forward-ports:
sourceports:
icmp-blocks:
rich rules:

I don't see port 5666/tcp listed there however when I run the command:
[root@huey xinetd.d]# firewall-cmd --zone=public --add-port=5666/tcp
success
[root@huey xinetd.d]#

Now I see this here
[root@huey xinetd.d]# firewall-cmd --zone=public --list-all
public (active)
target: default
icmp-block-inversion: no
interfaces: eno1
sources:
services: dhcpv6-client ssh
ports: 5666/tcp 2301/tcp 80/tcp 9102/tcp 10033/tcp 10032/tcp 10030/tcp 10022/tcp 10023/tcp 2381/tcp 10031/tcp
protocols:
masquerade: no
forward-ports:
sourceports:
icmp-blocks:
rich rules:

From the Nag server I am now getting this. What does this mean?
[root@nag ~]# /usr/local/nagios/libexec/check_nrpe -H 192.168.1.42
CHECK_NRPE: Error - Could not connect to 192.168.1.42: Connection reset by peer

This is a different error message.
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Re: check_nrpe : No route to host

Postby donnyforbes » Fri Jun 16, 2017 3:17 pm

Remote host:

[root@huey xinetd.d]# netstat -at | egrep "nrpe|5666"
tcp 0 0 0.0.0.0:nrpe 0.0.0.0:* LISTEN
tcp6 0 0 [::]:nrpe [::]:* LISTEN

[root@huey xinetd.d]# ps -ef |grep nrpe
nagios 10247 1 0 13:06 ? 00:00:00 /usr/local/nagios/bin/nrpe -c /usr/local/nagios/etc/nrpe.cfg -f
root 10800 21113 0 13:07 pts/1 00:00:00 grep --color=auto nrpe
[root@huey xinetd.d]#

From Nag Server
[root@nag ~]# /usr/local/nagios/libexec/check_nrpe -H 192.168.1.42
CHECK_NRPE: Error - Could not connect to 192.168.1.42: Connection reset by peer
[root@nag ~]#

Config /etc/xinetd.d/nrpe
"disable = no"

systemctl restart xinetd.service
systemctl restart nrpe

now I see a different message. Also, I have verified that the /etc/hosts.allow has the IP address of the Nagios server from the Remote Hosts.
[root@nag ~]# /usr/local/nagios/libexec/check_nrpe -H 192.168.1.42
CHECK_NRPE: Error - Could not connect to 192.168.1.42: Connection reset by peer
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Re: check_nrpe : No route to host

Postby donnyforbes » Mon Jun 19, 2017 10:12 am

when running the following command from the nagios server:
/usr/local/nagios/libexec/check_nrpe -H 192.168.1.42

I am seeing the following in the /var/log/messages
Jun 19 08:08:02 nag check_nrpe: Error: Could not complete SSL handshake with 192.168.1.42: rc=-1 SSL-error=5

Here is my /etc/xinetd.d/nrpe

[root@huey ~]# cat /etc/xinetd.d/nrpe
# default: off
# description: NRPE (Nagios Remote Plugin Executor)
service nrpe
{
disable = no
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
only_from = 192.168.1.186
log_on_success =
}

Here is my out put on remote host for nrpe port 5666

[root@huey ~]# netstat -at | egrep "nrpe|5666"
tcp 0 0 0.0.0.0:nrpe 0.0.0.0:* LISTEN
tcp6 0 0 [::]:nrpe [::]:* LISTEN

Here is a traceroute from nagios server to host
traceroute to 192.168.1.42 (192.168.1.42), 30 hops max, 60 byte packets
1 huey.sg1.allamericanasphalt.com (192.168.1.42) 2.597 ms !X 2.560 ms !X 2.540 ms !X

Here is a traceroute from host to nagios server
traceroute 192.168.1.186
traceroute to 192.168.1.186 (192.168.1.186), 30 hops max, 60 byte packets
1 nag.sg1.allameircanasphalt.com (192.168.1.186) 0.366 ms !X 0.353 ms !X 0.337 ms !X

I am not sure what I am missing here any help or ideas would be great. Thank you so much.
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Re: check_nrpe : No route to host

Postby tgriep » Mon Jun 19, 2017 12:51 pm

I think the issue now is that you are running the NRPE Agent as a daemon and also out of xinetd and that is causing a conflict.
If you want to run the Agent from xinetd, stop the service from running.
Then restart xinetd by running
Code: Select all
service xinetd retart


Then, if you run the following command as root on the remote server,
Code: Select all
netstat -anp |grep 5666


It should show you that it being started by xinetd like the example below.
Code: Select all
tcp        0      0 :::5666                     :::*                        LISTEN      3405/xinetd


Next, run the following on the Nagios server to test if it can connect to the Remote system
Code: Select all
/usr/local/nagios/libexec/check_nrpe -H 192.168.1.42
/usr/local/nagios/libexec/check_nrpe -H 192.168.1.42 -n


If either of the command work, you should be able to monitor the remote system.
If they both fail, post the output.

You should take a look at this guide for possible fixes when using the NRPE Agent and you cannot connect to the remote host.
https://assets.nagios.com/downloads/nagiosxi/docs/NRPE-Troubleshooting-and-Common-Solutions.pdf
Be sure to check out our Knowledgebase for helpful articles and solutions!
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Re: check_nrpe : No route to host

Postby donnyforbes » Mon Jun 19, 2017 2:01 pm

Actually I got this to work I have installed it now on 4 of my RHEL machines, I am now putting it on CentOS release 6.6 (Final) running into some issue I will post about it.

Thanks
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Re: check_nrpe : No route to host

Postby scottwilkerson » Mon Jun 19, 2017 2:08 pm

Thanks for letting us know. Please open a new thread if you have any other issues
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