diagnosing packetloss: x-files edition

Kees Jan Koster kjkoster at gmail.com
Mon Nov 28 13:15:49 UTC 2011


The packet loss I asked about earlier is getting weirder and weirder. I managed to track this down to being between two specific hosts exclusively.

When I run mtr from saffron to cumin I get packet loss reported on all intermediate routers. When I run mtr from cumin to saffron I get packet loss reported only on the end hop to saffron. 

But (and here it gets weird) when I run mtr from saffron to any other host on the Internet (although I have not tried exhaustively) I get *no* packet loss at all.

So what I expect now is that this is a hardware issue with the NIC in Saffron that only affects the traffic going to cumin and not traffic to any other host.

I will swap the NIC in saffron, but I just wanted to check:

* can this be caused by the fact that I use fwd rules in ipfw? Both Saffron and Cumin have such  rule.
* Can this be caused by IP aliassing? With Saffron and cumin use two IP addresses on their NIC.
* Anything else?
Kees Jan

kjkoster at kjkoster.org

I hate unit tests; I much prefer the illusion that there are no errors in my code.
                                                                 -- Hendrik Muller

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