"what do you want the Verifier to do? " anything he wants to with the understanding he has the equivalent of an unsigned message.
non-SMTP domain is the same as a non tcpip domain, no records associated with the protocol Bill Oxley Messaging Engineer Cox Communications 404-847-6397 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Charles Lindsey Sent: Wednesday, June 11, 2008 4:48 AM To: DKIM Subject: Re: [ietf-dkim] Discussion of Consensuscheck: Domain Existence Check On Tue, 10 Jun 2008 18:34:57 +0100, Douglas Otis <[EMAIL PROTECTED]> wrote: > On Jun 9, 2008, at 9:21 PM, Jim Fenton wrote: >> Since it apparently isn't clear: I am proposing retaining the >> NXDOMAIN domain validity check as a MUST. It is only the MX and A/ >> AAAA check that I'm proposing be changed from a SHOULD to a MAY. > > The situation created by MS Exchange creates a problem where just an > NXDOMAIN check is still problematic. While NXDOMAIN might occur for > any leaked X.400 address or typical "[EMAIL PROTECTED]", > NXDOMAIN results might also occur with any proxy SMTP addresses > assigned by MS Exchange. This occurs since MS Exchange assignments > and routing do not depending upon DNS records. Such an NXDOMAIN test > would disrupt messages created by the company where I work, for > example. In addition, unless the test goes one step further to > determine whether a domain appears to support SMTP, this would offer > far less utility in preventing address spoofing. Nor could just an > NXDOMAIN test offer protection for non-SMTP domains. But you have repeatedly failed to explain how a verifier could recognise and handle this case in a manner that did not leave a loophole for all the scammers and spoofers to walk through. If some message arrives with a From that includes a proxy SMTP address assigned by MS Exchange (which will surely result in NXDOMAIN), what do you want the Verifier to do? Is there some way that is can recognise this as a proxy address and let it through whilst still rejecting things apparently from the domain funny.ebay.com? If some companies using MS Exchange allow such messages to escape, then I am afraid that is just Tough! It is a stupid behaviour. I might accept that domains whose TLD clearly did not exist could be exempted from the NXDOMAIN check in ADSP. And what do you mean by a "non-SMTP domain. AKAIK the phrase is meaningless. -- Charles H. Lindsey ---------At Home, doing my own thing------------------------ Tel: +44 161 436 6131 Web: http://www.cs.man.ac.uk/~chl Email:[EMAIL PROTECTED]: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K. PGP: 2C15F1A9 Fingerprint: 73 6D C2 51 93 A0 01 E7 65 E8 64 7E 14 A4 AB A5 _______________________________________________ NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html _______________________________________________ NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html
