In message <19FB0BB1-9048-476A-A901-67F962A116B1@xxxxxxxxxxxxxxxxxxxx>, Keith M oore writes: > On Jun 8, 2011, at 11:35 PM, Mark Andrews wrote: > > > Have broken 6to4 relays is *good* for the long term health of the > > Internet. Applications should cope well with one address of a > > multi-homed server being unreachable. Billions of dollars have > > been wasted because this has not been seen as a basic requirement > > for applications. It really isn't any harder in most cases to do > > this right. > > Not that I disagree with the idea that applications should be able to > fail over from one address to another, but ... why do you assume that > the server is multihomed? Yes, that is a assumption which isn't always true but mostly is now. It's definitely true for the content providers complaining that 6to4 is stopping them deploying IPv6. > The problem with the broken 6to4 relay on an anycast address is that the > application (or user, or site) doesn't get to choose a different relay. The site can always pick a differnet relay as long as they know the IPv4 address of one. There used to be lists of them. The anycast address is or should be just a convenience function. I have suggested that ISP's could advertise 6to4 relay routers to customers via DHCP draft-andrews-v6ops-6to4-router-option, this can also be used to turn off 6to4 when it is known not to work (e.g. firewall, behind a NAT) or there is working IPv6. But rather than make the transition mechanism work there is this mind set that 6to4 needs to be killed. Mark > Keith -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@xxxxxxx _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf