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Re: DUL (was Re: RBL report..)

On Mon, Apr 03, 2000 at 11:15:29PM +1000, Hamish Moffatt wrote:
> On Mon, Apr 03, 2000 at 06:42:21AM -0400, Branden Robinson wrote:
> > Furthermore, that any issue is unspecified in an RFC does not mean that the
> > RFC's already address all issues that need to be addressed.
> Yes, exactly. Therefore ommission of any comment about dialup users
> making direct SMTP connections for mail delivery does not indicate
> that the RFCs think it is a good idea. They simply do not comment.
> You are taking this omission as support of your case where it is not.

And you're dropping context:

RFC 821:
   The SMTP provides mechanisms for the transmission of mail; directly
   from the sending user's host to the receiving user's host when the
   two host are connected to the same transport service, or via one or
   more relay SMTP-servers when the source and destination hosts are not
   connected to the same transport service.
   TCP Transport service

      The Transmission Control Protocol [3] is used in the ARPA
      Internet, and in any network following the US DoD standards for
      internetwork protocols.

      A computer in the internetwork environment on which mailboxes or
      SMTP processes reside.

RFC 821 therefore directly implies that hosts on the name transport service
may legitimately connect directly to each other to conduct SMTP

RFC 2505:

2.2.1. Direct MTA-to-MTA connections
   These recommendations are deliberately stronger than RFC1123, [3],
   and are there to assure that mail sent directly from a spammer's host
   to a recipient can be traced with enough accuracy; a typical example
   is when a spammer uses a dialup account and the ISP needs to have his
   IP address at the 'date-time' to be able to take action against him.

The last sentence is particularly instructive.  The authors of RFC 2505
quite obviously had the chance to say "because spammers use dialup
accounts, direct MTA-to-MTA connections where the caller is on a dialup
should not be accepted."

The IETF had a golden opportunity to throw their hat in the ring with the
DUL, and they didn't.  That is instructive.

While RFC 821 is pretty old (1982), RFC 2505 is not, being barely one year

G. Branden Robinson            |    You don't just decide to break Kubrick's
Debian GNU/Linux               |    code of silence and then get drawn away
branden@ecn.purdue.edu         |    from it to a discussion about cough
roger.ecn.purdue.edu/~branden/ |    medicine.

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