Re: [Asrg] Re: RMX evaluation

[Vernon Schryver <vjs@calcite.rhyolite.com>]

> From: J C Lawrence <claw@kanga.nu>

> ...
> Thanks, this is preferable to RMX.

It seems it also differs from Paul's intent.  However, I think the
differences are minor.  Both involve overloading MX RRs and depend
on using keys or values that are unlikely to be in current use.
I'm not sure, but I think Paul's intent (or Jim Miller's idea) does
better on that score.


> > To determine if an STMP client is authorized to send mail for the
> > sender domain name in the envelope Mail_From field
>
> I'd be happier if a straight forward check of the HELO==IP were added as
> a check.

I think that's independent of the idea of RMX checking.

The problem with checking HELO values is that simple implementations
will have many false positives.  It's a hassle to make an SMTP client
vary its HELO value depending on the IP address that operating system
picks on a multi-homed system.  Forcing the choice of source IP address
is impractical on multi-homed systems acting as firewalls and where
some interfaces are not reachable from various networks.  You would
at least want to let a big outfit use a HELO value of domain.com on
all of its SMTP servers.


Vernon Schryver    vjs@rhyolite.com
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