On Fri, Jun 08, 2007 at 07:03:48AM -0700, Douglas Otis wrote: > > On Jun 8, 2007, at 1:59 AM, Charles Lindsey wrote: > > >On Thu, 07 Jun 2007 14:41:22 +0100, Hector Santos > ><[EMAIL PROTECTED]> wrote: > > > >>Charles Lindsey wrote: > >> > >>>>In other words, not all MX query gives you IP addresses to try. > >>>>So in that case, you can have an MX that directs you to the > >>>>domain nomail.invalid (which has no A record, of course) and > >>>>that is the end of the matter. What is wrong with that? > >> > >>A change in long establish SMTP semantics and sending strategies. > > > >No. Just a way to say this domain does not want to receive any > >email, even though it has an A record. That MX should get cached > >(so no excessive load on the authoritative server). And > >nomail.invalid should also get cached, as a DNS failure, or so I > >have been informed, so no excessive load on the root servers; a > >smart DNS resolver will already have built into it that 'invalid' > >is not even worth looking up. I proposed it as an alternative to > >the suggested "MX .", which apparently had problems. > > This is a different name with a worse problem. An MTA is unlikely to > know that either "." or "nomail.invalid" is an invalid host name.
I didn't think they were proposing any particular name, just that after looking up the MX record, the corresponding A lookup failed. Surely all MTAs should be able to handle that case. Newer ones would realize that the domain in question doesn't want any mail, while older ones may retry till the message expires. -- :: Jeff Macdonald | Principal Engineer, Messaging Technologies :: e-Dialog | [EMAIL PROTECTED] :: 131 Hartwell Ave. | Lexington, MA 02421 :: v: 781-372-1922 | f: 781-863-8118 :: www.e-dialog.com _______________________________________________ NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html
