[Nagiosplug-help] check_icmp oddness

[Israel Brewster]

On Apr 9, 2008, at 12:18 AM, Andreas Ericsson wrote:
> Israel Brewster wrote:
>> On Apr 4, 2008, at 1:42 AM, Andreas Ericsson wrote:
>>> Israel Brewster wrote:
>>>> 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   
>>>> xx.xxx.xxx.33
>>>
>>> Add '-i 0.5s' to the command line and it might just magically start
>>> working. That will increase the packet interval, which can sometimes
>>> be too short when sending to a single host with multiple IP's.
>>> Especially if there's a firewall in between.
>> Well, that partially worked. If I increase that value to a  
>> ridiculously high amount (>10s) the packet loss drops to only about  
>> 33% (with 5 pings) rather than the 60% I get with the default  
>> settings. The pattern, however, is the same- only the first x  
>> packets received, where x is a constant in relation to the number  
>> of packets sent. One thing I find a bit confusing- the help text  
>> lists the -i switch as the "MAX packet interval". What determines  
>> the min? I would thing the minimum packet interval would be more of  
>> an issue than the maximum, although perhaps not considering that  
>> setting the maximum did make a difference. Thanks again!
>
> The minimum packet interval is determined as "if we've already seen
> replies to all packets we sent to this host, it's probably ready to
> get another one, so send it out instantly."

I'm wondering if it isn't this exact logic that is causing my  
problems. Is there any way to change this? -I does not help- see below.

> -I (capital i) is used to set a target_interval, which is used as
> the minimum value to wait between two packets going to the same
> target.

The capital i switch does in fact exist on the check_icmp plugin I  
have, however it is described (as mentioned in another reply to this  
thread) as MAX target interval, not min. Indeed, I can set this number  
up as high as I want (I  tried values up to 300,000), and it doesn't  
increase the execution time. If the plugin was sending 5 pings and  
waiting 300,000ms between pings, it should take about 20 minutes to  
complete. Therefore, that -I switch is obviously not setting  the  
minimum value to wait between two packets going to the same host.  
Additionally, while this switch, like the -i switch when doing  
multiple hosts, does improve things (check_icmp packet loss drops to  
33% rather than 60%) it doesn't actually fix anything. Thanks again  
for the suggestions and time on this issue.

-----------------------------------------------
Israel Brewster
Computer Support Technician
Frontier Flying Service Inc.
5245 Airport Industrial Rd
Fairbanks, AK 99709
(907) 450-7250 x293
-----------------------------------------------
> I'm not sure if that switch exists in the check_icmp.c the
> nagiosplug project ships, but it does in the one I've got.
>
> -- 
> Andreas Ericsson                   andreas.ericsson at op5.se
> OP5 AB                             www.op5.se
> Tel: +46 8-230225                  Fax: +46 8-230231