MTA Authorization Records in DNS

Document Charter MTA Authorization Records in DNS WG (marid)
Title MTA Authorization Records in DNS
Last updated 2004-09-22
State Approved
WG State Concluded
IESG Responsible AD (None)
Charter Edit AD (None)
Send notices to (None)


It would be useful for those maintaining domains and networks
to be able to specify that individual hosts or nodes are authorized
to act as MTAs for messages sent from those domains or networks.
This working group will develop a DNS-based mechanism for
storing and distributing information associated with that 

The primary current use case for this facility is to allow recipient
MTAs to confirm that peer MTAs' actions are authorized by
specific domains or networks. This will help combat a certain
class of domain forgery common in spam. The solution chosen,
however, should be generally useful for others which might
check this authorization data.

This working group is being chartered after extensive discussion of
the issues in the IRTF's Anti-spam Research Group, and it is presumed
that all active participants will be familiar with the documents 
produced there which describe the problem. It is not, however, an 
extension of that research group; it has no general writ to study spam 
or to produce specifications on the topic. It will not consider 
anti-spam abatement measures outside of the area of MTA authorization.

Because individual messages may be associated with multiple domains
(among them the domains present in the RFC2822 From, RFC2822 Sender,
the SMTP Mail-From, and the SMTP EHLO), the first task of the working
group will be to establish which of these identities should be
associated with MTA authorization. Once this decision has been
reached, it will limit the scope of further activity in this working 
group, and the chairs will rule out of order discussion related to 
schemes which use other identities as the basis of authorization.

The groups Technical Advisors will help ensure that the semantics of
proposals originating within this group are consonant with DNS
standards and syntax, and they will be available for early cross-review
to ensure that this work proceeds at an appropriate pace.

Upon chartering of this working group, the IESG intends to request
that the IRTF Chair and the Chairs of the IRTF's Anti-Spam Research 
Group seek publication of the listed input documents as Experimental 
RFCs, so that they are available on an archival basis. The IESG also 
intends to request that the RFC editor insert a note into each document
informing the reader that the IETF's MARID working group has taken on
the task of producing a standard in this area.