MTU Problem: Akamai,HE,GTT

Ignatios Souvatzis ignatios at
Mon Sep 22 11:16:02 CEST 2014


for at least one seems to hang most of the time for
some of my users. The reason is javascript code unconditionally loaded
from is an alias for is an alias for has IPv6 address 2a02:26f0:6a:191::eed has IPv6 address 2a02:26f0:6a:18f::eed

The latter two networks (or at least one of them) seem to block
IPv6 packets of too large a size.

I get replies to ICMPv6 echo requests with PING6(1280=40+8+1232 bytes)
but not bigger; I suspect an icmpv6 black hole somwehere.

However, some others show the same problem.

Working (addresses shortened):

2001:638:a000:: (fully inside DFN), but also


so I think it's not a problem with two DFN internal tunnels I'm aware of
(one inside Univ. of Bonn, one the UoB's next hop).

Not working:

2001:470::      	(routed through
2001:1900:2254::	(routed through
2a02:26f0:6a::  	(routed through

I can workaround on my workgroup edge router, but I guess it would be
more helpful if the real problem would be fixed.

	Ignatios Souvatzis

More information about the ipv6-ops mailing list