Hey, On 09/22/2011 04:54 PM, Michael Stefaniuc wrote: > Per Johansson wrote: >> 22 sep 2011 kl. 12:14 skrev Michael Stefaniuc: >> >>> Wow! /66? And that works? While the standard allows for that you "should >>> use /64" which everybody and his dog read it as that is the only thing >>> that needs to work and the only thing that get tested. IPv6 brings back >>> the class-full thinking which everybody has to painfully unlearn once >>> IPv6 catches on... >>> >>> "Safe" prefix length (especially if involving client devices) are: >>> /64 - LAN >>> /126 and /127 - point to point >>> /128 - host routes >> RFC3513 is quite more strict than "should": > Which is obsoleted by RFC4291, but that seems to have kept this > paragraph. Anyway the correct RFC term to make it mandatory is "must". > And it isn't a "must". Also the RFC4291 is from 2006 which is *old*. > >> All global unicast addresses other than those that start with binary >> 000 have a 64-bit interface ID field (i.e., n + m = 64), formatted as >> described in section 2.5.1. Global unicast addresses that start with >> binary 000 have no such constraint on the size or structure of the >> interface ID field. >> >> (2001:: has the binary prefix 001). So this might very well be the problem. > The same RFC4291 says: > Except for the knowledge of the subnet boundary discussed in the > previous paragraphs, nodes should not make any assumptions about the > structure of an IPv6 address. > > It might be the problem but not because of the RFC; it just might be a > typo as it is a manually set IP. > >> I've heard the reason for 64 bits is that it's what currently fits in most >> computer registers, but I don't know if it's true. > What really helps to understand IPv6 is: > - IPv6 is an old protocol >15 years. That predates the Internet taking over. > - IPv6 was designed based on the assumption that it will make the > Internet again a friendly, warm and cozy place; a big any to any network > without barriers/firewalls. > - IPv6 isn't better than IPv4, it is different. > - IPv4 still outperforms IPv6 in the new feature development. IPv6 is > trying to play catch up. A few things that were long ago deprecated in > IPv4 are still mandatory for IPv6 to be "standards compliant". > - Don't assume that if the IPv6 standard says something the > implementations really follow that. Test, test, test. > > So no, the /64 host part has nothing to do with current hosts having > 64bit registers now. I'm pretty sure that they were hoping to have > 128bit computers by now. It had more to do with thinking that a globally > unique identifier for the host is a good think to have and the MAC > address already provided that with 48bits. But 48 isn't a nice number so > it was rounded up to 64 which makes for a nice "design" as it is half of > the IPv6 address. > Discussion aside, seems that using /64 works, so I'm keeping that. With the change testbot.winehq.org works again when using ipv6. I am not sure why it was set to /66, so I just hope nothing breaks as a result of this change.
~Maarten