> > If you have the capability, is there any reason not to place the
> > subscriber email address in the To: header of list messages,
> > particularly announcement lists?
> You lose the ability for the MTA to group messages going to recipients
> sharing the same domain inside a single envelope and deliver them together.
> As a result it could take much longer to deliver messages and use more
It turns out that individual deliveries take more bits but paradoxically
are actually faster on all but the most overloaded networks due to the
increased parallelism. That's not an important consideration unless
you're running a huge list on a 28.8K modem which I hope nobody does any
Nonetheless, I think that putting the individual recipient's address in
the To: line is a pretty bad idea. Many PC mail programs have weak
filtering features and can't filter on arbitrary headers, so without the
list name in the To: header, they can't put mailing list mail in separate
folders. I agree that looking for your own address in the To: and Cc:
line isn't a bad spam heuristic, but if you're going to do that, you can
put "whitelist" rules for your mailing list mail first.
John Levine, firstname.lastname@example.org, Primary Perpetrator of "The Internet for Dummies",
Information Superhighwayman wanna-be, http://iecc.com/johnl, Sewer Commissioner
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