[atlas] Disabling one measurement on my probe...

On Aug 28, 2013, at 3:00 AM, Emile Aben <emile.aben at ripe.net> wrote:

> Hi Warren,
> 
>>> Due to much stupidity my probe lives behind 2 NATs (don't ask).
>>> Anyway, one of the NATs / firewalls is suddenly throwing hissyfits and
>>> logging a bunch of messages like:
>>> [00005] 2013-08-27 17:33:29 [Root]system-critical-00435: ICMP
>>> fragment! From 78.46.37.134 to 192.168.15.207, proto 1 (zone Untrust,
>>> int ethernet3). Occurred 2 times.
>>> 
>>> I can see the Measurement IDs that are causing this (1019675,
>>> 1019728), but I have two questions:
>>> 1: is there a way to disable specific measurements from a specific
>>> probe and
>> No there is not an easy way yet, although we are working on it and users
>> will be able to add/remove probes.
>> Anyhow, from what I see these two UDMs are already stopped so you
>> shouldn't have any more cases with these two.
>>> 2: did anything change recently with the "Ping" measurement, like the
>>> packet size for example?
>> Among other options[1] user can change the packet size and from what I
>> see it's 48bytes for the first one 1485 for the second.
> 
> I'm the culprit here.

No worries. 

> I did start a couple of UDM measurements with
> large packet-sizes to try and provide some data from what RIPE Atlas
> sees when sending fragmented packets (this is a discussion on the
> NANOG-list currently), and apparently your probe is one of the cases it
> caught (though the log message doesn't specify if it blocked the
> fragments or not).

I guess I make a good test case then :-)

I get a log email for each of the failures, I can easily tell procmail to just send those mails to /dev/null (I'm not at that house, so I cannot tell the firewall to not log) 

This is interesting / useful research, please don't let my bizarre home network deter you from running tests, etc. I was just interested…

W

> 
> Emile Aben
> RIPE NCC
> 
>>> 
>>> I *did* spend some time reading the list archives and documentation,
>>> but was not able to find an answer.
>>> 
>>> W
>>> P.S: And yes, I will sometime remove the NATs, but cannot until there
>>> is another ISP available -- I live in a 3rd world country where any
>>> broadened is a luxury, and multiple providers is more than one can
>>> reasonably expect…
>>> 
>>> 
>>> 
>>> -- 
>>> "When it comes to glittering objects, wizards have all the taste and
>>> self-control of a deranged magpie."
>>> -- Terry Pratchett
>>> 
>>> 
>>> 
>>> 
>>> 
>> Regards,
>> Andreas
>> 
>> [*] You can see the different options users can set for the ping UDMs if
>> you scroll a bit down on this page
>> https://atlas.ripe.net/doc/udm#creating-a-new-measurement
>> 
> 

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