request for help in finding a blackhole

[Jogi Hofmüller]

On Tue, May 04, 2010 at 12:48:24PM -0500, Drake Wilson wrote:
> Quoth Jogi Hofmüller <jogi at mur.at>, on 2010-05-04 19:26:27 +0200:
> > There is a tunnel between hops 2 and 3 where MTU drops to 1476 (PMTUD
> > working correctly).  Nevertheless, the largest pakets I can get over the
> > wire - all the way up to he.net - have 1450 bytes.
> 
> As a data point, I can get pings of 1410 IPv6 payload bytes between
> drache.begriffli.ch (2001:470:1f0f:c9::2), which is behind an HE 6in4
> tunnel, and www.mur.at (2a02:3e0::21:80).  Larger than 1410 bytes gets
> no response.  Local MTU between drache and zwischenschaltung is 1472.

This is quite helpfull in a certain way, thanks.  Looking at the path
from us to you and comparing it to the other way round, we have
asymmetry on the way.  My guess is this is not intented ... I send this
Cc to our upstream.

Largest ping pakets I get through to drache.begriffli.ch have 1402 bytes
payload.

traceroute to drache.begriffli.ch (2001:470:1f0f:c9::2), 30 hops max, 40 byte packets
 1  v200-fe2-r1ko.mur.at (2a02:3e0::1)  7.079 ms  7.290 ms  7.291 ms
 2  vlan706.wien6.aco.net (2001:628::1)  7.468 ms  7.695 ms  7.698 ms
 3  aconet.rt1.vie.at.geant2.net (2001:798:10:10dd::1)  8.316 ms  8.509 ms  8.512 ms
 4  so-7-0-0.rt1.pra.cz.geant2.net (2001:798:cc:1001:1301::1)  14.007 ms  14.242 ms  14.245 ms
 5  so-6-3-0.rt1.fra.de.geant2.net (2001:798:cc:1301:1401::2)  21.708 ms  21.948 ms  21.951 ms
 6  so-5-0-0.rt1.ams.nl.geant2.net (2001:798:cc:1401:2201::2)  29.288 ms  29.524 ms  29.504 ms
 7  so-4-0-0.rt1.lon.uk.geant2.net (2001:798:cc:2201:2801::2)  36.061 ms  37.635 ms  37.854 ms
 8  2001:450:2002:6f::1 (2001:450:2002:6f::1)  36.274 ms  35.621 ms  35.603 ms
 9  paix.ipv6.he.net (2001:504:d::10)  182.951 ms  190.324 ms  190.531 ms
10  10gigabitethernet1-1.core1.lax1.ipv6.he.net (2001:470:0:34::2)  198.526 ms  197.772 ms  198.050 ms
11  10gigabitethernet1-2.core1.dal1.ipv6.he.net (2001:470:0:3a::2)  205.769 ms  206.175 ms  216.346 ms
12  gige-gbge0.tserv8.dal1.ipv6.he.net (2001:470:0:78::2)  215.080 ms  214.964 ms  214.916 ms
13  zwischenschaltung.begriffli.ch (2001:470:1f0f:c9::1)  224.190 ms  228.387 ms  232.977 ms
14  drache.begriffli.ch (2001:470:1f0f:c9::2)  233.814 ms  222.013 ms  222.790 ms

> traceroute to www.mur.at (2a02:3e0::21:80) from 2001:470:1f0f:c9::2, 30 hops max, 60 byte packets
>  1  zwischenschaltung.begriffli.ch (2001:470:1f0f:c9::1)  0.472 ms  0.468 ms  0.416 ms 
>  2  begrifflich.tunnel.tserv8.dal1.ipv6.he.net (2001:470:1f0e:c9::1)  16.509 ms  16.714 ms  15.672 ms 
>  3  gige-g2-14.core1.dal1.ipv6.he.net (2001:470:0:78::1)  18.130 ms  20.807 ms  22.780 ms 
>  4  10gigabitethernet1-4.core1.chi1.he.net (2001:470:0:c4::1)  46.684 ms  46.217 ms  41.291 ms 
>  5  ibx-chi.ip6.tiscali.net (2001:504:0:4::3257:1)  46.927 ms  43.989 ms  41.354 ms 
>  6  xe-2-1-0.nyc20.ip6.tinet.net (2001:668:0:2::1:1481)  80.681 ms  79.285 ms  76.807 ms 
>  7  xe-5-2-0.lon11.ip6.tinet.net (2001:668:0:2::1:1072)  159.303 ms  156.890 ms  *
>  8  xe-0-3-0.lon10.ip6.tinet.net (2001:668:0:2::1:1622)  159.263 ms  156.882 ms  154.935 ms 
>  9  * * *         
> 10  * * *         
> 11  Aconet.tu-637.sar1.Amsterdam1.Level3.net (2001:1900:5:2::a2)  226.214 ms  224.457 ms  222.389 ms 
> 12  2001:628::a089:0:1 (2001:628::a089:0:1)  230.819 ms  230.740 ms  225.948 ms 
> 13  www.mur.at (2a02:3e0::21:80)  231.697 ms  229.288 ms  227.128 ms 
> 
>    ---> Drake Wilson

j.
-- 
j.hofmüller                                http://users.mur.at/thesix/
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