RE: Question on restricting incoming mail from Mail Lists

At 23:51 2003-07-04 -0700, Noarmun E. Mailer did say:
> ...no, I'm not using a wildcard and then trying to kludge procmail into
> sorting it all out.
I didn't say you were.  What I suggested was that a great many people who 
have gobs of addresses are simply wildcarding their domain at the MTA level 
(lots of hosting outfits set things up this way for their customers, so as 
to reduce the number of edits necessary on the part of that client).  If 
the MTA configuration is as I described, then when someone sends a message to:
        supercalafrigidexpletivealoquacious(_at_)netgods(_dot_)us

it'll be _accepted_ by your server and delivered into your account.  Even 
though you didn't set up anything explicitly to accept mail for that address.
If you're actually configuring your MTA with _each_individual_ alias, then 
that's great - your MTA will reject mail directed to addresses which 
weren't specifically configured.
> I have one inbox per email list right now.
Physical inbox (i.e. separate mail account), or simply separate incoming 
address at your domain, but which is aliased to the same account?
> Someone who gets the subscription email address can then spam into my list 
> inboxes.  I simply want to block mail that doesn't come from the list.
As David has already pointed out, you'll ditch legitimate offlist replies 
if you take that route.
What I'm trying to point out though is that if you're going to limit mail 
according to SENDER, you really shouldn't need to limit it according to 
recipient.  Certainly, there can be times when that is appropriate, but is 
really isn't for what you're trying to do - when a _spammer_ spams you (or, 
as David said, when someone legitimately mails you offlist), the Sender: 
won't identify the list -- and if it did, your Sender + To: logic would 
have been matched, and you'd have accepted the message anyway.  Thus, To: 
is unnecessary.  Further, spammers are HIGHLY unlikely to send you spam at 
OTHER addresses of yours, using Sender: from different lists you're 
subscribed to - IF they were so bright as to forge Sender: addresses to be 
from lists, surely they'd be forging them To: addresses which they 
harvested FROM those same lists?
You're really much better off employing standard spam avoidance techniques, 
using some good RBLs at the MTA level, and a good LDA-time filter (either a 
series of procmail filters, or use procmail to invoke SpamAssassin or the 
like).
I still use several role-based addresses, it's not for spam 
purposes.  However, my _generic_ mailing list account is intentionally 
separate from my standard contact address, and that IS intentional, and 
spam-related - I can more freely resubscribe to lists with another address 
and ditch my generic list address if it becomes a liability to me - but 
good spam filtering has made that unnecessary thus far.
[big snip again]

---
 Sean B. Straw / Professional Software Engineering

 Procmail disclaimer: <http://www.professional.org/procmail/disclaimer.html>
 Please DO NOT carbon me on list replies.  I'll get my copy from the list.


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