af%sei.ucl.ac.be@CUNYVM.CUNY.EDU ("Alain FONTAINE ", Postmaster - NAD) (12/15/89)
Hi. May I ask if anybody is currently playing with the experimental mailbox RR's ? Is there any software using them ? Do most implementations of the DNServers already handle them ? Seems exactly what I need to handle our 'logical addresses'. Thanks for any info. /AF
08071TCP@MSU.BITNET (Doug Nelson) (12/20/89)
>Hi. May I ask if anybody is currently playing with the experimental >mailbox RR's ? Is there any software using them ? Do most implementations >of the DNServers already handle them ? Seems exactly what I need to >handle our 'logical addresses'. Thanks for any info. /AF It is my understanding that MB, MG, and MR are obsolete, and that MX was designed specifically to be a replacement and generalization of the other three. Doug Nelson Michigan State University
pvm@VENERA.ISI.EDU (Paul Mockapetris) (12/22/89)
> >Hi. May I ask if anybody is currently playing with the experimental > >mailbox RR's ? Is there any software using them ? Do most implementations > >of the DNServers already handle them ? Seems exactly what I need to > >handle our 'logical addresses'. Thanks for any info. /AF > > It is my understanding that MB, MG, and MR are obsolete, and that MX > was designed specifically to be a replacement and generalization of the > other three. > > Doug Nelson > Michigan State University At the time the DNS was designed, everybody agreed that we needed to support mail. One faction argued for "mailbox binding" or routing based on the whole destination (e.g. PVM@ISI.EDU) while another argued for "agent binding", in which only the right-hand side, or ISI.EDU in this case, is used. The difference is whether you route mail by individual mailbox or by oragnization/host/whatever. The "agent binding" folks proposed a mechanism using MF and MD RRs. This was replaced by MX. Agent routing is the standard today. The "mailbox binding" folks had a lot more trouble deciding what to do, since they also felt that mailing lists, exploders, etc were on their agenda. Basically no agreement was possible for the same sort of reasons as you see different mailers for UNIX. However, I felt it was important to at least illustrate the possibilities, so the mailbox RRs are in the DNS spec. I have been told by different people that they are exactly right, completely wrong, or somewhere in between. Every so often, I get inquiries asking whether anyone has implemented it. I know some places that have threatened to, and have seen several viewgraph implementations. I don't know if anyone has it in production. It seems clear to me that: An implementation based on the current specs might be useful for some sites. An extended version could easily be better. Standardizing one or getting mailbox binding elevated to an Internet standard might be easier than getting agreement on a standard shoe size, but need not be so. This discussion should move to namedroppers. paul