[Nagiosplug-help] check_icmp oddness

Israel Brewster israel at frontierflying.com
Fri Mar 28 23:33:00 CET 2008

I am having some difficulty using the check_icmp plugin to monitor a  
number of my hosts, specifically Linksys RV082 routers running the  
latest firmware. What's happening is if I have a command line such as:

./check_icmp -n 2 -m 1 -w 3000,80% -c 5000,100% xx.xxx.xxx.111  

(or the equivalent from the nagios configs) it works (I have a dual- 
WAN configuration on the router, both IP's are for the same device).  
However, if I change the -n argument to 3, I get 33% packet loss.  
Changing the -n argument to 4 gives 50% packet loss, etc. This is  
consistent and reproducible-only the first two packets ever get  
through. check_ping, however, works perfectly, even if I tell it to  
send something like 10 packets, as does an ongoing ping directly from  
the command line.

So this leaves me needing one of two questions answered: either a) how  
can I fix check_icmp so it works properly, or b) what can I use  
instead of check_icmp that will allow me to monitor both ports of the  
router simultaneously? I actually did ask that second question in the  
nagios users mailing list, and check_icmp was the best answer I got. I  
can, of course, write a wrapper script for check_ping to make it  
behave the same as check_icmp in this regard, but I would consider  
that a last resort. Thanks!
Israel Brewster
Computer Support Technician
Frontier Flying Service Inc.
5245 Airport Industrial Rd
Fairbanks, AK 99709
(907) 450-7250 x293

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