fp.o content via IPv6

[Daniel Drown]

[I apologize for sending so many messages on this topic, this probably belongs
on a different mailing list]

> 1. the packet too big ICMP message should be coming from your tunnel box

I talked this over with a friend who knows more about networking, and he
pointed out that I had this point backwards.  What I said is only true if
you're uploading.  When you're getting the web page (downloading), the ICMP
fragmentation needed message (from the DSL provider's termination router) gets
sent to the 6to4 tunnel endpoint (the publicly run end), which probably just
throws it away.  So the webserver never gets a notice that its packets are
being dropped.

That said, the various MSS fixes (point #2 and the origional poster's iptables
command) avoid the problem for TCP.