6to4 status (again)

Martin Millnert martin at millnert.se
Tue Feb 26 01:23:25 CET 2013

Hi Kevin,

On 25 feb 2013, at 22:48, Kevin Day <kevin at your.org> wrote:

> I know this was brought up in November, but I didn't see much of a consensus…
> We run one of the public 6to4 relays. Lately traffic to it has been growing very rapidly and I'm really not sure why. Other people shutting their public relays down?


> More AAAA records are making more people fall back to 6to4?

Unlikely, tunnels aren't used much for http, there aren't that many single-stacked high-volume IPv6-sites out there.

> Idiots using it for DDoS?


> For most of 2012 the usage averaged about 50-100mbps, but lately we're seeing sustained levels of 500mbps-900mbps. I'd rather not deploy 10GE on our 6to4 box just to handle the traffic growth.

A low-hanging fruit, so to speak, of an explanation, is that other networks' preference towards your relays in BGP has increased. That, or latency-improvements of your relay, are in my experience the two major sources of step-shift changes of relaying throughput.

> Has anyone here looked at public 6to4 usage recently and seen similar trends?

Not recently, but a considerable time ago, and then i found that 98%+ of the throughput of a 6to4 and teredo-relay I ran was simply nothing more than a rendezvous point between the two tunneling protocols.
Oh, and AAAA:s preferred in dual-stack scenarios by either are insignificant.
DHT-clouds and Bittorrent-trackers however handle quite a bit of IPv6-nodes, assisted by large cable companies and similar's DPI bandwidth throttling boxes not handling the overlay protocols.

> Part of me is thinking we should just rate limit the box to something more reasonable. While it's still running, it'll be slow enough that hopefully people will move to a better transitional technology. My fear is that it will cause more "v6 sucks, it's so slow" and people shut it off without looking at why.

Honestly, draw that argument to its conclusion and don't get caught in an inverse of the to me familiar stale mate of swedish public alcohol politics discussing the pros and cons of adding saturday opening hours of the state owned alcohol distribution monopoly(*).

I.e., turn it off and do not look back. :-)
Look ahead.

Individuals shutting off 6to4 has very little bearing on the bottom line, i think.

Best regards,
* "it's a state operated monopoly so that people don't drink themselves to death [which people do if the alcohol shop is open, apparently], but it would be convenient if it's open a bit more"

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