[Nagiosplug-help] check_icmp reporting 100% pkt loss when host is "pingeable"

Alejandro Mejía Evertsz amejia at carmeltelecom.com
Mon Mar 27 07:49:03 CEST 2006

Wow! That was fast :D
Thanks Andreas, I appreciate it ;)

I've done what you suggest.
As the problem started about 8 to 10 hours after starting nagios, I'll keep
you posted on my results.

Thank you!

-----Mensaje original-----
De: Andreas Ericsson [mailto:ae at op5.se] 
Enviado el: Monday, March 27, 2006 9:28 AM
Para: Alejandro Mejía Evertsz
CC: nagiosplug-help at lists.sourceforge.net
Asunto: Re: [Nagiosplug-help] check_icmp reporting 100% pkt loss when host
is "pingeable"

Alejandro Mejía Evertsz wrote:
> Hello everyone.
> I wrote this message to the nagios-users list, but had no reply. Maybe
> here’s the right place to post my problem.
> I was having problems with “segmentation fault” using check_ping command,
> and I found some info on this list regarding that and suggesting to use
> check_icmp instead.
> Check_icmp is great
 it’s faster, and don’t consume much resources, but
> having this problem:
> It works fine for some hours, but suddenly all hosts are reported as
> with packet loss of 100%
> I get the net interface down with ifconfig, and then back up again, and
> nothing. I have to restart the server and then it works fine again.

This is most likely the result of an old check_icmp running on a system 
where pid's are more than 16 bits (i.e. the pid can be larger than 
65535, as on recent FreeBSD f.e.). You can upgrade to the latest 
check_icmp and the problems should go away.

If the fix isn't available in a recent package from the official 
nagiosplug package you should be able to use the one found at 

You can notice if the fix is available from the nagiosplug project by doing

$ grep -q 'pid & 0xffff' check_icmp.c && echo "Fix available"

in the "plugins" directory of the expanded tar-ball.

> The hosts I’m monitoring are up, and if I use a normal “ping” command to
> reach them, I get reply.
> Also if I use “check_ping” from shell, I get PING OK - Packet loss = 0%,
> = 109.81 ms

Matches completely with other bug-reports re the same issue, so feels 
fairly safe to say you should be running a functional version within a 
couple of minutes.

> If it helps:
> I’m using FreeBSD 6.0 Stable and installed nagios from ports.

That helps indeed (see above). :)

In the future, please put such info on top of the message, preferrably 
along with the version of the plugins you're using.

Andreas Ericsson                   andreas.ericsson at op5.se
OP5 AB                             www.op5.se
Tel: +46 8-230225                  Fax: +46 8-230231

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