[Nagiosplug-help] check_icmp oddness

[Israel Brewster]

On Apr 21, 2008, at 6:42 AM, Andreas Ericsson wrote:

> Israel Brewster wrote:
>> 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.
>
> It's hard to know without knowing exactly which version you're using.
> There has been about 20 bugs filed (and fixed) in check_icmp since it
> first was released, but unfortunately the nagiosplug project version
> and the one we're releasing aren't exactly the same. None of our
> customers are having this issue, although we always recommend them to
> disable all firewall rules for packets coming from the server we put
> there (and things like this doesn't happen unless there's a rate- 
> limiting
> firewall causing it).
>
>>> -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.
>
> Looking at the help; yes. Looking at the code; no. This brings us back
> to making it excessively hard to fix the problem without knowing  
> exactly
> which version you're using.
>
> I'll look into this though and see if I can get my version to forcibly
> wait between sending packets without modifying the code. If that  
> works,
> it *might* work for you too, otherwise I'll just send you the code for
> the one I've got.
>
> Unfortunately I just got home from one weeks vacation, so I'm swanked
> in work (more than usual, that is). Poke me again if you haven't heard
> more about this come wednesday or so.
>
> Cheers, and thanks for being persistent while at the same time concise
> and a generally nice person :)

I just get the following when I try to check the version from the  
command line:

# ./check_icmp --version
./check_icmp: illegal option -- -
./check_icmp: illegal option -- e
./check_icmp: illegal option -- r
./check_icmp: illegal option -- s
check_icmp: No hosts to check
# ./check_icmp -V
#

However, this version was built from the OpenBSD 4.2 ports tree, and  
the nagios plugins 1.4.11 package. From the source, I see Last  
Modified: $Date: 2007-12-11 05:57:35 +0000 (Tue, 11 Dec 2007) $,  
Revision: 1861
-----------------------------------------------
Israel Brewster
Computer Support Technician
Frontier Flying Service Inc.
5245 Airport Industrial Rd
Fairbanks, AK 99709
(907) 450-7250 x293
-----------------------------------------------

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