[Mimedefang] Verizon and greylisting

Jeff Rife mimedefang at nabs.net
Sun Dec 24 14:51:36 EST 2006

On 24 Dec 2006 at 12:54, Joseph Brennan wrote:

> The message comes into the list host with the writer of the message
> as MAIL FROM.  The bounce goes out of the list host as MAIL FROM:<> and
> RCPT TO the several list owners.

Correct, but for most list owners, the list host is generally going to 
be "internal" with respect to the gateway running MIMEDefang, it's not 
much of an issue.

> David makes a good point though about smaller systems.  You might
> happen to know that no two people on your system are co-list-owners.

In the rare cases where there are multiple list owners who aren't 
forwards from "internal" users (for example, the owners of 
"biglist at somewhere.tld" would likely all have "@somewhere.tld" accounts 
that actually get the mail to start with, and this might then be 
forwarded to other domains throughout the world), there might be a time 
when you get two recipients for a DSN, but some mailing list software 
now uses some other "special" sender for list bounces to owners.

It really doesn't matter, though, since the second owner would just be 
tempfailed, so it would eventually get through.  Only a non-conforming 
sending implementation would be a problem, so any real mailing list 
would work fine.

My method makes disabling "VRFY" be more useful than if you still allow 
multiple recipients for mail from "<>".

Sure, you get more chances to filter because of the lack of milter 
callbacks with "VRFY" and the ability to greylist From/To/IP, but it's 
still less effective.

Jeff Rife |  
          | http://www.nabs.net/Cartoons/OverTheHedge/HDTV.gif 

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