Re: [Exim] double check DNS

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著者: Matthew Byng-Maddick
日付:  
To: exim-users
題目: Re: [Exim] double check DNS
On Mon, Nov 19, 2001 at 02:39:42PM +0000, Nigel Metheringham wrote:
> IMHO reverse DNS has no place whatsoever in mail handling. If you use


I'd like to see that a mail server sending me mail has a valid reverse
lookup (as this helps with abuse reports, often), by which I mean, one
that will forward lookup to one or many IPs one of which is the IP that
you did the reverse lookup on.

> it as a policy then trying to match up reverse DNS to sender domain is


Yes. for the reasons you explained.

> doomed to total failure, requiring a match between HELO fqdn and IP has
> a better justification, but is totally useless for real policy control.


That isn't necessarily a reverse lookup. It is better to try and do a
lookup of the IP address of the machine that has just said HELO, and see
if that corresponds to the machine that is connecting. This stops all
those received lines in spams of:

  Received: from spammer_1234@??? ([2.5.1.3] helo=yahoo.com) by
     ...


by stopping that happening in the first place.

MBM

-- 
Matthew Byng-Maddick         <mbm@???>           http://colondot.net/