[ietf-dkim] Signalling DKIM support before DATA
dotis at mail-abuse.org
Tue Aug 8 11:13:44 PDT 2006
On Aug 8, 2006, at 10:54 AM, Hallam-Baker, Phillip wrote:
> The way to do this (if it should be done) would be to use the SMTP
> extension mechanism.
> For example. Define a command option SDATA, Receiver advertises it
> in response to EHLO, sender uses it to present signed data in place
> of DATA.
> Might be a better implementation but the point is we should use the
> SMTP extension mechanism not invent our own.
Something a bit simpler that would not require changing the MTA
code. Use a host-name convention. This would be apparent at the
EHLO without requiring negotiations. In essences,
_dkim.mx01.example.com makes an assurance that:
1) this host-name will authenticate
2) a DKIM client policy can be applied
In conjunction with the DKIM client policy, there could also be
MAIL_FROM policies that offer name relationships. For example, this
list might be a PTR RRset of names. This might be a lookup of the
If a truncation occurs, a subsequent lookup of the (<query-
domain>._DKIM-MP.<mail-from-domain>, PTR) extends this list
A domain name of "." might signal that the list is closed.
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