On Wed, Mar 26, 2008 at 12:10:38AM -0700, SM wrote: > At 19:32 25-03-2008, Bill Manning wrote: > > er... what about zones w/ A & AAAA rr's and no MX's? > > when I pull the A rr's, you are telling me that SMTP > > stops working? That is so broken. > > SMTP will still work as the above case is covered by the implicit MX rule. presuming the existance of an MX... (thats the "implicit" part of the "rule"). > The implicit MX rule creates an ambiguity during the transition from > IPv4 to IPv6. That's discussed in Section 5.2 of the draft: > > "The appropriate actions to be taken will either depend on local > circumstances, such as performance of the relevant networks and any > conversions that might be necessary, or will be obvious > (e.g., an IPv6-only client need not attempt to look up > A RRs or attempt to reach IPv4-only servers). Designers of > SMTP implementations that might run in IPv6 or dual stack > environments should study the procedures above, especially the > comments about multihomed hosts, and, preferably, provide mechanisms > to facilitate operational tuning and mail interoperability between > IPv4 and IPv6 systems while considering local circumstances." > what this daft is trying to do is force the presumptive existance of an MX in a zone into an explict rule that forces the existance of an MX, else SMTP fails. > We could look at the question by asking whether the fallback MX > behavior should be an operational decision. But then we would be > treating IPv4 and IPv6 differently. IPv4 and IPv6 are different. --bill > > Regards, > -sm > > _______________________________________________ > IETF mailing list > IETF@xxxxxxxx > https://www.ietf.org/mailman/listinfo/ietf -- --bill Opinions expressed may not even be mine by the time you read them, and certainly don't reflect those of any other entity (legal or otherwise). _______________________________________________ IETF mailing list IETF@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf