On Tue, Mar 25, 2008 at 03:56:14PM +0100, Frank Ellermann wrote: > Bill Manning wrote: > > >> FWIW, I'd like that... > > >>>> Clarity can be established and interoperability _improved_ > >>>> by limiting discovery to just A and MX records. Perhaps a > >>>> note might be included that at some point in the future MX > >>>> records may become required. > > >>> Again, I have no problem with this approach if that's what > >>> the consensus is. > > >> ...and that, too. > > > so what is supposed to happen when I remove all "A" RR's from > > my zones? > > I'm not sure if we are talking about the same issue. For SMTP > as it used to be since RFC 821 clients trying to find a server > accepting mail for x@xxxxxxxxx look for y.example MX records, > and if they got something they locate corresponding servers > "by name" (A or AAAA), all details as explained in 2821bis. > > If they got nothing with their MX query RFC (2)821 and 2821bis > said that the client should try y.example directly "by name", > it could be an ordinary host with an SMTP server at port 25. right. example.com. soa ( stuff ) ns foo. ns bar. ; mailhost aaaa fe80::21a:92ff:fe99:2ab1 is what i am using today. the RFC's have the right idea. > For various reasons mentioned in this thread this "fallback" > or "implicit MX rule" isn't a good idea today, and some folks > like to get rid of it for AAAA. RFC 2821 didn't say that > this is also supposed to work for IPv6, and therefore 2821bis > isn't forced to stick to it. its not a bad idea either, just that some folks are feeling grumpy. RFC 2821 didn't say - and the presumption should be that since IPv6 is just like IPv4... then the IPv4 methods shoudl work. > For the domain with only one SMTP host also almost nothing is > new, it is only encouraged (by the proposed note) to publish > this name in an MX record. what is being proposed is -FORCING- people to use an RR type they may not want to use. > You are not supposed to remove any A records from your zones. > You are not supposed to do anything at all, because you have > MX records as it should be... :-) er, NO. SMTP has no dependence on what may or may not exist in the DNS. Forcing SMTP to depend on DNS is a huge mistake. And yes Virginia, I plan on removing A rr's from my zones (eventually) > > Frank > > _______________________________________________ > 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