current 6to4 state

Eric Vyncke (evyncke) evyncke at cisco.com
Mon Nov 12 09:21:31 CET 2012


Indeed, running a BitTorrent client exhibits a lot of Teredo and 6to4 peers BECAUSE on BitTorrent the peer is identified by its IPv* address and not by a DNS, so, for each peer there is only one address and source address selection is not used (there is no choice but using this IPv* address); hence, Teredo and 6to4 can be used and are used indeed.

Web servers are accessed by FQDN and in the case of A and AAAA records, source address selection is used and will NEVER (IMHO) use 6to4 or Teredo, hence, content owner (such as Steinar's employer) do not see 6to4 anymore which is a Good Thing of course

-éric

> -----Original Message-----
> From: ipv6-ops-bounces+evyncke=cisco.com at lists.cluenet.de [mailto:ipv6-ops-
> bounces+evyncke=cisco.com at lists.cluenet.de] On Behalf Of Ivan Shmakov
> Sent: lundi 12 novembre 2012 06:49
> To: ipv6-ops at lists.cluenet.de
> Subject: current 6to4 state
> 
> >>>>> Steinar H Gunderson <sesse at google.com> writes:
> >>>>> 2012/11/10 Ivan Shmakov <oneingray at gmail.com>:
> 
>  >> Which makes me wonder on what are the costs of operating one's own  >>
> “IPv6-to-6to4” relay?  As it seems, the “no valid route to  >> 192.88.99.1”
> case is much easier to troubleshoot that the converse  >> “no valid route to
> 2002::/16” one, so the latter may indeed deserve  >> some extra care.
> 
>  > It's simple; if you wish, you can add a 6to4 decapsulation on every  >
> server if you wish.
> 
> 	Well, my question was about 6to4 /encapsulation/, actually.
> 
> 	AIUI, there's likely to be just a single 6to4 relay
> 	decapsulating the packets sent from 6to4 hosts to the IPv6 nodes
> 	proper.  However, there'll be a lot of such relays on the
> 	reverse direction, and thus it's the broken /encapsulating/
> 	relay case that'd likely be much harder to troubleshoot.
> 
>  > I've done it a few times, with a marked increase in reliability to  >
> 6to4-using hosts.  (Nowadays it's quite irrelevant, though, since  > 6to4 is
> all but extinct.)
> 
> 	My numbers are hardly representative (and are rather a
> 	back-of-the-envelope calculation), but while operating a
> 	BitTorrent DHT6 node for a short time, I've observed that 6to4
> 	constitutes over 90% of all /48 prefixes seen, being responsive
> 	for 36% of all messages seen by the node.  The latter number, if
> 	any, should be more representative of the present 6to4
> 	deployment, due to the possibility of 6to4 nodes using a dynamic
> 	IPv4 address, and thus more than one IPv6 /48 prefix, and also
> 	because /48 may prove itself a bit coarse for the native IPv6
> 	case.
> 
> --
> FSF associate member #7257



More information about the ipv6-ops mailing list