Ted Hardie wrote: > At 1:29 PM -0700 3/23/09, Fred Baker wrote: >> OK. So what you told me was, perhaps, that hairpinning is a concern. >> From my perspective, if a host B' in B's network tries to use one of >> its external addresses rather than preferring the address available >> behind the DMZ, it didn't correctly execute the algorithm in RFC 3484, >> which calls for it to prefer the address most similar to its own. > > I note that RFC 3484 refers to site-local, rather than ULAs. Is there work > done/underway to revise the algorithm to explain whether ULA maps exactly > to site-local? Given that ULAs allowed for "informed consent" routing among > adult networks, it seems more like it gets treated/should be treated > exactly as other global scope addresses, with possibly impaired reachability. > But, as I said, I am not all sure I understand how to map my previous > understandings of scope onto this work.
I don't think a host or app can make assumptions about what a ULA means. It's not inherently a "site" local or private address. There are cases where a ULA will work better than a global address, and there are cases where the opposite is true. And the meaning of "better" depends not only on the topology of the network seen by the host but also on the needs of an application. (e.g. is it better to use an address that is stable, or to have an address that is globally reachable in referrals? even then, an app cannot reasonably assume that a ULA is more stable just because it's a ULA.) Keith _______________________________________________ nat66 mailing list [email protected] https://www.ietf.org/mailman/listinfo/nat66
