check_nrpe socket timeout after n seconds

[manish2tiwari]

Hi All,

We are facing check_nrpe socket timeout after 10 seconds error whenever we are trying to use check_nrpe command for one of our Unix server.
We are using Red Hat Enterprise Linux Server release 5.6 (Tikanga) as the target server and virtual machine as the Source Nagios server.

We are able to use the same command for our windows server.

We have done the configuration settings as required in all the configuration file but not able to run the command on target server. local host in unix server is working fine and giving below output

Command: /usr/local/nagios/libexec/check_nrpe -H localhost
Output: NRPE v2.12

Please let us know if we are missing anything here.

Thanks in advance,
Manish
+004917687766033

[slansing]

Are you using this check to see if they can communicate?:

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/usr/local/nagios/libexec/check_nrpe -H host.ip.address.here

Or a custom check? Just making sure you are trying the same thing. Do you have the NRPE standard port 5666 opened on the RHEL server?

[scottwilkerson]

Also, for some background also, did you use the our Linux agent installer?

And, on the machine with the agent installed can you see it listening on port 5666

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 netstat -lnp |grep 5666

Finally you may need to verify you don't have a firewall blocking port 5666

[manish2tiwari]

Hi Scott,

The command (netstat -lnp |grep 5666) is giving below reply:

tcp 0 0 0.0.0.0:5666 0.0.0.0:* LISTEN 19004/nrpe

Hi Slansing,

Yes i am using that check on the Nagios hosting server and getting socket timeout error there.

Thanks,
Manish

[slansing]

Can you check your nrpe.cfg file and make sure that you have your XI server listed as an allowed host?:

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vi /usr/local/nagios/etc/nrpe.cfg

[manish2tiwari]

yes /usr/local/nagios/etc/nrpe.cfg contains below line:

allowed_hosts=10.123.4.21

10.123.4.21 is our Nagios XI server.

Thanks,
Manish

[slansing]

Did you restart the NRPE service after editing the nrpe.cfg?

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service nrpe restart

Are you running any custom firewalls?

[lmiltchev]

Can you also run the following command and the output of it?

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iptables -L -n | grep 5666

[manish2tiwari]

@Slansing: service restart nrpe is giving command cannot found error, is there any specific path where i have to run it.

@limiltchev: iptables -L -n | grep 5666 command in my Nagios XI server giving below output:

tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:5666
ACCEPT - tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:5666
ACCEPT - tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:5666
ACCEPT - tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:5666
tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:5666
ACCEPT - tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:5666
ACCEPT - tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:5666
ACCEPT - tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:5666

Thanks,
Manish

[scottwilkerson]

Not sure why you have so many extra lines in there, also you have a single line without ACCEPT in front of it

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tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:5666

Here is what I would recommend, edit /etc/sysconfig/iptables-config and change the following to yes
IPTABLES_SAVE_ON_STOP
IPTABLES_SAVE_ON_RESTART

Then stop iptables, and edit /etc/sysconfig/iptables to have a line like

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-A INPUT -m state --state NEW -m tcp -p tcp --dport 5666 -j ACCEPT

Then start iptables

also to restart nrpe you may need to run

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/etc/init.d/nrpe restart