[167640] in North American Network Operators' Group
Re: Help me make sense of these traceroutes please
daemon@ATHENA.MIT.EDU (Jeroen Massar)
Tue Dec 24 18:55:31 2013
Date: Wed, 25 Dec 2013 00:55:46 +0100
From: Jeroen Massar <jeroen@massar.ch>
To: sam@circlenet.us, nanog@nanog.org
In-Reply-To: <a4f63787cf110e28fa1ef921e3b15ae6@www.circlenet.us>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On 2013-12-25 00:16, Sam Moats wrote:
> Hello Nanog community,
> I would like to enlist your help with understanding this latency I'm
> seeing.
You are likely seeing the effects of asymmetric routing.
[..]
> Tracing route to xxx.yyy.ie [193.1.x.x]
www.heanet.ie by chance? :)
Though you could use for instance:
http://planchet.heanet.ie/toolkit/gui/reverse_traceroute.cgi
to do a reverse traceroute, do make sure you force your connectivity to
IPv4 as that host will do IPv6 too. (locally nullrouting the destination
/128 is the trick I use for 'disabling' IPv6 temporarily).
Otherwise the HEANET folks are extremely helpful and clued in, you can
always ask them for help with issues. It is the end-of-year though and
those Irish folks have lots of really good whiskey, Guinness thus you
might have to be patient till the new year.
Alternatively, you could use a tool like 'tracepath' or 'mtr' as those
reports multiple answers to a response and also check for the TTL on the
return packets.
Greets,
Jeroen
