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Re: Transition Planning for IPv6 as mandated by the US Govt

  • From: Nathan Ward
  • Date: Sat Mar 15 03:27:55 2008

On 15/03/2008, at 7:19 PM, Glen Kent wrote:
I have another related question:

Do all ISPs atleast support tunneling the IPv6 pkts to some end point?
For example, is there a way for an IPv6 enthusiast to send his IPv6
packet from his laptop to a remote IPv6 server in the current
circumstances if his ISP does not actively support native IPv6?

Yes - 6to4 and Teredo.

6to4[1] if your router (or some host with an unfiltered non-RFC1918 address) supports it.
Teredo[2] if you're behind NAT or some other filtering.

- These are enabled by default in Vista.
- Enable them in XP SP2 by typing 'netsh interface ipv6 install'.
- Apple Airport Extreme has 6to4 enabled by default if it is your NAT router (stateful firewall, allowing new connections outgoing- only by default)
- Cisco supports 6to4 and has for years.
- Linux and FreeBSD both support 6to4 (no OpenBSD, can't recall RE. NetBSD).
- Teredo support in Linux and *BSD with 'miredo' software - it's in APT and FreeBSD ports.

Azureus bittorrent client uses IPv6 for DHT. More DHT IPv6 bidirectional relationships than DHT IPv4 bidirectional relationships. So, it's not just IPv6 "enthusiasts".
Numbers here:
More up to date numbers when I get around to processing them [3].

Upcoming version of uTorrent will enable IPv6 (so, Teredo/6to4) on XP SP2 as part of the install process - currently Azureus only uses it if it's enabled already.

If you're providing content or network services on v6 and you don't have both a Teredo and 6to4 relay, you should - there are more v6 users on those two than there are on native v6[1]. Talk to me and I'll give you a pre-built FreeBSD image that does it, boot off compact flash or hard drives. Soekris (~$350USD, incl. power supply and CF card), or regular server/whatever PC.
Also, if you want config for 6to4 on Cisco, email me and I'll hook you up so I'm not spamming the list with it, alternatively Google. It's about 10 lines, and requires you to inject an anycast IPv4 /24 and an IPv6 /16 in to your IGP(s).


Nathan Ward

[1] RFC3056
[2] RFC4380, see also
[3] I made this up. But seriously, prove me wrong. Current numbers (well, I got bored of waiting, processing 800MB of PCAP takes a while) are that I've had 1,402,634 unique host addresses talk to one of my test host over IPv6/6to4 - and that's just people running a recent version of Azureus with a public unfiltered IPv4 address, and have 6to4 enabled.
Imagine what the numbers are like for Teredo users (ie. no requirement for public unfiltered IPv4 address, works through NAT).
Imagine what the numbers are for people not running Azureus.
Yeah, you get the idea.
I really should get around to writing this stuff up properly.. If there's anyone out there who wants to roll some code to pull some stats out of PCAP files so I don't have to process this stuff with cut sed awk uniq etc. please contact me. Oh also if anyone knows Java and can hack some changes in to Azureus for me that'd be useful - it only seems to want to listen on one IPv6 address, I want it to listen on.. 3.