On Sat, Jun 09, 2007 at 07:51:51AM -0700, Douglas Otis wrote: > The discovery process itself might provide a solution. For a message > to contain a valid email-address, the domain of this address MUST > locate either an MX or A record. The DKIM WG could strongly > recommend A record discovery be deprecated, and that only MX records > be used for discovery. Within a few years, it should be possible to > obsolete use of A record discovery. An email-address would not be > valid without an MX record. This would mean that policy placement > adjacent to the MX record would be the only location any policy > record would need to exist. In this case, the discovery process > itself indicates whether or not the sub-domain is USED/UNUSED.
Are you referring to the process that some MTAs follow? For example, if a MTA needs to deliver a message, it is suppose to find a MX for the right hand side of the email address and deliver it to the eventual A record (Hector's claim that some MX records return IPs confused me). Some MTAs, when they don't find an MX record, just lookup an A record instead and deliver to the resulting IP. If that's the case, shouldn't the deprecating of A lookups when a MX lookup fails be brought to the SMTP group? -- :: 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
