Who is operating IPv6 tunnel services?

Posted by Andree Toonk - January 18, 2009 - BGPmon.net, IPv6 - 5 Comments
In order to migrate to IPv6 different methods are available, one of them is using IPv6 in IPv4 tunnels. These tunnels come in different flavors, static tunnel or dynamic tunnels. Dynamic tunneling protocols such as 6to4 and teredo use anycast technology. A number of organizations have employed 6to4 or teredo relays and it’s not always easy for an end user to see which relay you are using because they all have the same IP address. I’ve created a list of Autonomous systems that are announcing the 6to4 (IPv4 and IPv6 2002::/16) anycast prefix. The same is done for autonomous systems that announce the teredo relay prefix (2001::/32). This list is dynamically generated by analyzing all BGP announcements and scanning for the relevant tunnel prefixes.  The data available on this website contains data that goes back to 2001 (using RIB snapshots) and will be updated continuously. So if you’re interested in a list of current or historically autonomous systems that operate a 6to4 routers or teredo relays please take a look here: One last tip, the week interval in the url limits the result to active entries. So in case of week=4, you will only see relays that have been seen in the last 4 weeks. For example, If you would like to go back in time and also see the 6to4 or teredo relays in January 2005 you would use a week interval of 210 http://www.bgpmon.net/6to4.php?week=210


  • Martin Levy says:

    Hi guys! Two things:

    1) There’s a typo on the URL’s on this page – it’s the ones in ()’s.
    2) What’s the definition of “last seen” when the “IPv4 anycast” is newer? How can that happen – If you know it’s still anycasting then the last seen date would be the same.

    Thanks in advance,


  • the lists to see which AS’s are using a certain Teredo relay seems to be incorrect. For example, if I click on AS1257, it shows AS12859 is using the relay in AS1257 which I know for a fact is not the case 😉 AS12859 does accept the prefix from AS1257, but it’s not active.

    Also, the list seems to be incomplete, I know for a fact that many more AS’s are using the AS12859 relay, for example:

    route-server.he.net> sh ipv6 bgp 2001::/32
    BGP routing table entry for 2001::/32
    Paths: (4 available, best #1, table Default-IP-Routing-Table)
    Advertised to non peer-group peers:
    2001:7f8:1::a501:2859:2 from 2001:470:0:12::1 (
    Origin IGP, metric 1, localpref 140, valid, internal, best
    Community: 6939:1000 6939:6000 12859:3001 12859:4000
    Originator:, Cluster list:
    Last update: Fri Jan 16 08:19:40 2009

  • andree says:

    Hi Martin,
    Thanks for catching the typo. That’s fixed now.

    Regarding the definition of last-seen. BGPmon.net uses the RIS bgp data sources to detect hijacks and things suchs as 6to4 and teredo prefixes. These data files contain BGP updates and withdraw messages.

    If for example the prefix 2002::/16 is seen in the update, the timestamp, origin AS and (ris)peerAS are extracted. This data is stored in the database. The last-seen field is represents when was the last time an update for this prefix, from this originAS and peer AS was seen.
    So last-seen indicated when the last update was seen, it does not mean that was the last time the prefix was in the RIBs.

    It’s perfectly possible to have different last-seen times for the IPv4 and IPv6 anycast prefix. As they are announced as different prefixes.

  • andree says:

    Hi Daniel,

    The text “Click on the entry to see which AS’s are using this Teredo relay ” is actually not quite correct. It should be:
    “Click on the entry to see which RIS peer AS’s are using this Teredo relay”

    Regarding the issue “AS12859 is using the relay in AS1257”.
    You will see first-seen 2008-10-01 last-seen 2008-10-01
    Apparently BIT/ AS12859 has been using (maybe temporary) this relay in October 2008 for a while.

    According to the same analysis AS12859 has started announcing it’s own relay server somewhere that same month (October 2008) :
    I think this is a great initiative! It looks that quite some others are using this teredo relay. I wonder how much traffic a typical teredo relay generates? It seems Tele2 is handling around 190Mb/s (http://ipv6.tele2.net/mrtg/kst-teredo-1.swip.net.html)

  • Hi Andree,
    that makes sense, thanks for the explanation.
    Traffic stats for the AS12859 relay: http://teredo.bit.nl/ (this is on interface level, so IPv4 + IPv6 aggregated).

    Keep up the good work!

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