Thanks.  Will have to see how to do this with postfix.

Ron

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Ron Nutter                          [EMAIL PROTECTED] 
Network Infrastructure & Security Manager
Information Technology Services                        (502)863-7002
Georgetown College                                     
Georgetown, KY                                            40324-1696
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-----Original Message-----
From: Matt Kettler [mailto:[EMAIL PROTECTED] 
Sent: Friday, August 12, 2005 3:45 PM
To: Ronald I. Nutter
Cc: users@spamassassin.apache.org
Subject: Re: Question on NO_DNS_FOR_FROM Rule


Ronald I. Nutter wrote:
> I am getting quite a bit of spam coming in today that is scoring well 
> below the 5.0 min (i.e. 2.4 or so out of 5.0).  The common thread I am

> seeing is that they all fail the NO_DNS_FOR_FROM Rule.  I noticed that

> it is only set to 1.1.  I am thinking about raising the value of this 
> score.  I don't think that I should loose any email, should I  ?  
> Guess I have a simplistic view of the world that no legitimate company

> would run a mail server without a valid A and MX record.
> 
> Thoughts ?

Their DNS, or your internet connection, could be down at the time you
scan mail.

Thus, this test could occasionally hit for legitimate companies with a
proper MX record if either their end end has flaky DNS hosting.

Generally, I find it infinitely better to check this at SMTP time.

i.e. turn OFF accept_unresolvable_domains in sendmail.cf.

This way you temp-fail messages with unresolvable return paths, and they
eventually deliver when the source domains DNS is resolvable again.

No legitimate mail should ever have an unresolvable envelope return path
(except the NULL return path, which isn't counted as unresolvable by
sendmail).

I know *I* certainly don't want such a message in my mail queues. Any
DSN that might get generated is certain to end up stuck in my mail
queue, then eventually double-bounce into postmaster's box. Ick.

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