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Article: 1735
From: Jim Hermann - UUN Hostmaster
Date: 2007-09-23 10:39:24 -0400
Subject: Re: milter-link problems

Removal...........: milters-request@milter.info?subject=remove
More information..: http://www.milter.info/#Support
--------------------------------------------------------

 

> On Sep 23, 2007, at 9:21 AM, Jim Hermann - UUN Hostmaster wrote:
> > Sep 23 08:02:49 host sm-acceptingconnections[16916]: l8ND2OZu016916:
> > from=<dwscubaservicem@scubaservice.com>, size=0, class=0, nrcpts=0,
> > proto=ESMTP, daemon=MTA, relay=localhost [222.253.62.134] (may be  
> > forged)
> >
> > Sendmail appears to accept the invalid PTR record.  Another 
> example of
> > invalid PTR record:
> >
> > Sep 23 07:51:09 host sm-acceptingconnections[12739]: l8NCp22N012739:
> > from=<Amos@rogers.blackberry.net>, size=0, class=0, nrcpts=0,  
> > proto=SMTP,
> > daemon=MTA, relay=domain.not.configured [69.113.40.86] (may 
> be forged)
> >
> > In both cases, Sendmail bounced the message for other reasons, not  
> > the lack
> > of a valid domain name in the PTR.
> 
> Sendmail won't bounce a message for lack of a valid domain 
> name in the  
> PTR, it's not configured to do that.

milter-null and milter-link reports:  Sep 23 08:53:15 host
milter-link[6143]: 02725 NOQUEUE: host localhost [222.252.134.89] from
unknown TLD.   I don't think that they bounce the message.

> Like I said, there's two macro values available, one which is just  
> "what's the untrusted PTR" (used in the messages above), and 
> one which  
> has the double-resolution turned on.
> 
> What happens, essentially, is that if they don't equal each 
> other, it  
> adds the "may be forged" qualifier in the received headers.

The Sendmail 8.13.7 default setting does not require that the PTR domain
name match the domain name.  The RFC 2317 does not require that a PTR match,
only that a valid PTR exists.  For example, my SMTP server sends email from
host.xxx.net on two IP Addresses, one has a PTR with host.xxx.net and the
other is host2.xxx.net.  At either IP Address, Sendmail reports:
220 host.xxx.net ESMTP Sendmail 8.13.7/8.13.7; Sun, 23 Sep 2007 09:37:08
-0500

What Sendmail FEATURE invokes the double-resolution macro?

Jim






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