Because if we put that in the spec then we've effectively gotten rid of x= because no one would use it then and that's what he wants perhaps?
Scott K On 04/19/2006 18:54, [EMAIL PROTECTED] wrote: > Why would a verifyer refuse a message that had a value for x=? > "Verifiers MAY support checking of x= values or may refuse to > accept messages with the x= tag." > thanks, > Bill > > > -----Original Message----- > From: [EMAIL PROTECTED] on behalf of Douglas Otis > Sent: Wed 4/19/2006 6:01 PM > To: Stephen Farrell > Cc: ietf-dkim > Subject: Re: [ietf-dkim] Attempted text for x= with DSN considerations > > Proposed: > > x= Signature Expiration (plain-text, OPTIONAL, default is > no expiration). The format is the same as the "t=" tag, > represented as an absolute date, not as a time delta from the > signing timestamp. > > Verifiers who support x= should consider a signature invalid > when the [received] time at the verifier is past the > expiration date. Verifiers that do not support x= and > forward messages, may refuse acceptance of messages > when the x= tag is present to avoid causing DSNs. > > When a signature becomes invalid, and is not accepted by a > subsequent MTA, a mechanism to rate-limit initial senders > may be required to control the level of DSNs. If a signature > is initially found invalid for this reason, then normal rules > apply, so the signature SHOULD be treated the same as if > cryptographic checking had failed, or as if the public key > could not be retrieved. > > Verifiers should not assume that there is any particular > relationship between the x= value and the life cycle of a > public key. Signers MAY include an x= value at their > discretion. > > Verifiers MAY support checking of x= values or may refuse to > accept messages with the x= tag. The value is expressed as > an unsigned integer in decimal ASCII, with the same constraints > on the value in the "t=" tag. The value of the "x=" tag MUST > be greater than the value of the "t=" tag, if both are present. > > > INFORMATIVE NOTES: > 1) Messages with invalid signatures or x= parameters > may be rejected by subsequent MTAs. > 2) When the signer has no reason to include any > particular value, then this tag is better omitted. > 3) There is no particular reason to include values far > into the future, e.g. if it expected that a verifier > might not see the message for a long time. In such > cases omitting x= will probably be better. > > _______________________________________________ > 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 _______________________________________________ NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html
