MTU Problem: Akamai,HE,GTT

[Ignatios Souvatzis]

Hi,

for at least one weatheronline.co.uk seems to hang most of the time for
some of my users. The reason is javascript code unconditionally loaded
from connect.facebook.net.

connect.facebook.net is an alias for connect.facebook.net.edgekey.net.
connect.facebook.net.edgekey.net is an alias for e3821.dspe1.akamaiedge.net.
e3821.dspe1.akamaiedge.net has IPv6 address 2a02:26f0:6a:191::eed
e3821.dspe1.akamaiedge.net 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

2a00:19e0::
2001:608::
2001:200::

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 he.net)
2001:1900:2254::	(routed through he.net/yahoo)
2a02:26f0:6a::  	(routed through gtt.net)

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

Regards,
	Ignatios Souvatzis