On Thu, 10 Mar 2005, Kenneth Porter wrote: > > It looks to me like it's similar to SPF but addresses the hostname in the EHLO > message rather than the one in the MAIL FROM message. I'm still unclear how > the target field in the SRV record is used.
The reason it uses SRV records is a clever optimisation. When you look up a SRV record the DNS server returns the SRV record (containing the authorization status) in the answer section, and any address records belonging to the target in the additional section (one of which must be the same as the client's IP address). Thus a single DNS lookup gives you enough information to check that the client is who it claims to be and that it is supposed to be talking SMTP. Tony. -- f.a.n.finch <[EMAIL PROTECTED]> http://dotat.at/ NORTH ROCKALL MALIN: WEST 6 TO GALE 8, VEERING NORTHWEST 5 TO 7. RAIN OR SHOWERS. MODERATE OR GOOD.
