request for help in finding a blackhole

Jogi Hofmüller jogi at mur.at
Tue May 4 19:26:27 CEST 2010


dear all,

We have been trying to play this via our upstream, but they were not
successfull in bringing this matter any further.  So I hope someone here
can be of help.

There is a blackhole between us [1] and hurricane electric.  All the
usual symptoms aply:  ping6 works, larger pakets disapear.  This is the
traceroute from my office machine:

traceroute to www.he.net (2001:470:0:76::2), 30 hops max, 80 byte packets
 1  v201-fe2-r1ko.mur.at (2a02:3e0:1::1)  0.256 ms  0.278 ms  0.326 ms
 2  vlan706.wien6.aco.net (2001:628::1)  4.762 ms  5.092 ms  5.094 ms
 3  aconet.rt1.vie.at.geant2.net (2001:798:10:10dd::1)  5.104 ms  5.114 ms  6.530 ms
 4  so-7-0-0.rt1.pra.cz.geant2.net (2001:798:cc:1001:1301::1)  11.464 ms  11.876 ms  11.889 ms
 5  so-6-3-0.rt1.fra.de.geant2.net (2001:798:cc:1301:1401::2)  19.248 ms  19.443 ms  20.696 ms
 6  so-5-0-0.rt1.ams.nl.geant2.net (2001:798:cc:1401:2201::2)  27.079 ms  27.716 ms  27.680 ms
 7  so-4-0-0.rt1.lon.uk.geant2.net (2001:798:cc:2201:2801::2)  36.237 ms  34.842 ms  34.839 ms
 8  2001:450:2002:6f::1 (2001:450:2002:6f::1)  33.736 ms  34.859 ms  34.846 ms
 9  paix.ipv6.he.net (2001:504:d::10)  179.603 ms  179.117 ms  179.074 ms
10  10gigabitethernet1-2.core1.fmt1.ipv6.he.net (2001:470:0:2e::1)  190.764 ms  189.628 ms  189.589 ms
11  he.net (2001:470:0:76::2)  179.894 ms  179.970 ms  180.268 ms

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.

I might add that a lot of other IPv6 things work flawless here ;)

Any help is appreciated!  If you need a pingable target, use www.mur.at
which is dual-stacked.

[1] mur.at, AS39837, 2a02:3e0::/32

Thanks in advance!
j.
-- 
j.hofmüller                                http://users.mur.at/thesix/
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