On Jul 27, 2006, at 12:53 PM, Michael Thomas wrote:
Douglas Otis wrote:
The "I sign some mail" (an open-ended list) also indicates that
when a signature is damaged by a mail-list for example, this
source should be considered valid for their OA. An open-ended
list also allows positive annotations, but with fewer delivery
failures or support calls.
I have no idea what an "OA" or "open ended list" is, but I
seriously doubt it. Preferential treatment based on unverifyable
DKIM-Signature bits is an invitation for abuse.
OA was short-hand for Originator Address (OA) as defined in Eric
Allman's SSP draft. This OA, or perhaps the Signing Address (SA) as
defined thin the Base draft, would be where a DKIM related policy
might be found.
While DNS zone delegations are possible, these require formal
arrangements, rather than less formal arrangements currently common
place when using an ISP for outbound traffic. This ISP might now
employ DKIM signing under their domain. The existence of the DKIM
signature offers a valuable tool for combating abuse, where much of
this value would be unrelated to an OA or SA policy assertion. The
concerns related to the OA or SA are likely important to a minority
of DKIM signing domains being spoofed, especially when an exacting
assertion leads to a delivery failure.
To permit less formalized arrangements between OAs or SAs and an ISP
offering DKIM signing under their domain, DKIM policy could be
defined as just being a list of designated signing domains for the OA
or SA. This list could have two modes. One mode could then be
defined as being "open-ended" which means the list is not complete.
A list that is not "open-ended" would be "closed-ended" or "fixed."
A "close-ended" list indicates that the OA or SA has declared an
explicit set of valid signing domains. A designated signing domain
list (DSDL) and a single flag indicating open or closed permits every
policy required by Bill, for example.
Perhaps another major benefit from this approach would be improved
envelope handling when a greater range of associations are made
possible.
-Doug
_______________________________________________
NOTE WELL: This list operates according to
http://mipassoc.org/dkim/ietf-list-rules.html