[98648] in North American Network Operators' Group
Re: [policy] When Tech Meets Policy...
daemon@ATHENA.MIT.EDU (Mark Andrews)
Tue Aug 14 21:59:59 2007
Date: Wed, 15 Aug 2007 11:58:52 +1000 (EST)
From: Mark Andrews <Mark_Andrews@isc.org>
To: nanog@merit.edu
In-Reply-To: <7C3FEAF3-A83F-4D17-B54A-9ECB5A684C53@mail-abuse.org>
Errors-To: owner-nanog@merit.edu
>This comment was added as a follow-on note. Sorry for not being clear.
>
>Accepting messages from a domain lacking MX records might be risky
>due to the high rate of domain turnovers. Within a few weeks, more
>than the number of existing domains will have been added and deleted
>by then. Spammers take advantage of this flux. Unfortunately SMTP
>server discovery via A records is permitted and should be
>deprecated.
All it would require is a couple of large ISP's to adopt
such a policy. "MX 0 <self>" really is not hard and benefits
the remote caches.
>Once MX records are adopted as an _acceptance_
>requisite, domains not intended to receive or send email would be
>clearly denoted by the absence of MX records. SMTP policy published
>adjacent to MX records also eliminates a need for email policy
>"discovery" as well. Another looming problem.
Better yet us MX records to signal that you don't want to
receive email e.g. "MX 0 .". It has a additional benefits
in that it is *much* smaller to cache than a negative
response. It's also smaller to cache than a A record.
Since all valid email domains are required to have a working
postmaster you can safely drop any email from such domains.
>Don't accept a message from a domain without MX records. When there
>is no policy record adjacent to the MX record, there is no policy,
>and don't go looking.
>
>-Doug
>
