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Re: [spf-discuss] another style of dns records

2005-12-08 08:49:25
In <20051208180526(_dot_)0009a97b(_at_)agri-home> Agri <agri(_at_)7m(_dot_)ru> 
writes:

Hello

May be another style of dns records could be useful,
ISPs could set txt (or PTR) records for reverse zones which
define that client with a ip address cannot send any mail with smtp
outside ISP's network.
But a syntax must be defined.

Hi.

There have been several proposals along this line made over the last
several years.

The ones I can think of off the top of my head are:

Unified-SPF/ptr:
Basically, you put a "v=spf1 -all" record in the rDNS for machines
that shouldn't send email

Selective Sender:
MTAMark:
I forget the details of these, but they were input documents to the
MARID working group.

Another, that I forget the name of, is one I like best.  It involved
defining a standardized naming of machines in the rDNS.  Basically, it
required something like "dynamic" in all rDNS records of machines that
shouldn't send email.  This is actually what many major ISPs are
doing, although they aren't following any standard.


None of these systems are better than what I think should be done: If
a machine shouldn't be sending email, then port 25 should be blocked
by the firewall for that machine.  There isn't any reason why everyone
else in the world should act as the firewall.  If port 25 packets are
supposed to be rejected, the place to do it is at the source, not the
destination.


-wayne

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