6to4 strangeness

Kevin Loch kloch at hotnic.net
Wed Feb 15 00:08:14 CET 2006

Iljitsch van Beijnum wrote:
> Hi ipv6-ops,
> I'm seeing a 6to4 problem that I haven't seen before... Maybe one of  
> you can explain this. Today, http://www.osx86project.org/ announced  
> that they are IPv6-capable. But it didn't work for me: with a source  
> address in 2001:1af8::/32 with UUNET NL as a main transit network I  was 
> unable to reach the site. Turns out they use a 6to4 address  (based on 
> the IPv4 address 2002:42EB:B46B::2.

It seems that there are a couple different things going on here...

First, I can ping and traceroute to it fine:

traceroute6 to www.osx86project.org (2002:42eb:b46b::2) from 
2001:4810:0:100::1, 64 hops max, 12 byte packets
  1  iad0-stf.hotnic.net  0.373 ms  0.284 ms  0.213 ms
  2  2002:42eb:b46b::2  98.401 ms *  98.553 ms

PING6(56=40+8+8 bytes) 2001:4810:0:100::1 --> 2002:42eb:b46b::2
16 bytes from 2002:42eb:b46b::2, icmp_seq=0 hlim=123 time=98.322 ms
16 bytes from 2002:42eb:b46b::2, icmp_seq=1 hlim=123 time=97.887 ms
16 bytes from 2002:42eb:b46b::2, icmp_seq=2 hlim=123 time=98.248 ms

And I can connect to it with telnet on port 80, but:

Connected to www.osx86project.org.
Escape character is '^]'.
GET / HTTP/1.1
[Our DNS server shows that [No Host] does not exist]
Connection closed by foreign host.

It doesn't give me a chance to enter a Host: line and disconnects
after the first input line.  The "[Our DNS server..." message is an odd
response to an http query...

Firefox seems to fallback to ivp4 for each url retrieved on the page,
even images which takes a long time to load.

So it seems that even with a working IPv6 path in both directions
there is an application level problem.

> #trace
> Protocol [ip]: ipv6
> Target IPv6 address: www.osx86project.org
> Source address: 2001:1AF8:6:0:204:27FF:FEFE:249F
>   1  *  *  *
>   2  *  *

Can that router get to any 6to4 addresses?

- Kevin

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