[Nagiosplug-help] check_icmp problems

[Israel Brewster]

I think I may have mentioned this before, and if so I apologize, but  
it remains an issue so I thought I'd try again. I am having a problem  
using check_icmp where it consistently shows a number of my hosts (all  
of which are on the same hardware) as having 60% packet loss, even  
though a straight ping against these hosts returns no packet loss,  
even when doing a ping flood (thus implying that the issue is not rate  
limiting). More specifically, it would appear that all but the first  
two packets are being dropped- if I increase the number of pings to  
10, I get 80% loss, if I decrease the number of pings to 4 I only get  
50% loss, and if I drop to two pings, I get no loss. Increasing the  
delay between packets has no noticeable effect until the delay numbers  
get ridiculously high, also indicating that rate limiting is not the  
problem here.

FWIW, I was having the same problem with the fping program from  
smokeping, and it turned out that this was caused by the fping binary  
using the ICMP sequence number to indicate which host the packet was  
for, rather than incrementing the sequence number with each packet  
sent to a given host. After patching that, fping worked fine. Perhaps  
this is the same problem with check_icmp? I seem to recall someone  
giving a patch for that a while back, but I could never get the patch  
to apply properly, so I don't know if it would have worked. Thanks for  
any help/function patches that can be provided!

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Israel Brewster
Computer Support Technician
Frontier Flying Service Inc.
5245 Airport Industrial Rd
Fairbanks, AK 99709
(907) 450-7250 x293
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