[Mailman-Users] Automatic deletion of posts by non-members of a list

[Brad Knowles]

At 5:32 PM -0400 2006-05-25, Peter C.S. Adams wrote:

>  In the old days, this was certainly true, but today, when 70-80% of all
>  emails on the internet are spam, you may easily find that rejecting all
>  those messages will (a) eat up a lot of your internet bandwidth, and (b)
>  exacerbate the problem by telling the "sender" of the message -- which will,
>  90% of the time, be a forged address -- that "their" mail was rejected.

	This is a pretty sore point in the business right now.

	Which is more important?  Wasting your bandwidth, eating up your 
MTA resources, and potentially notifying spammers that they didn't 
get through?  Or simply throwing everything away, including messages 
that might have had great personal or business significance?


	Think about spam in general.  Which is worse?  Dealing with large 
quantities of spam to try to find the relatively small amount of 
legitimate mail?  Or throwing everything away that might potentially 
be spam, possibly including important messages from your boss, your 
spouse, your parents, your children, your co-workers, prospective 
business partners, etc...?


	Myself, I tend to err on the side of caution.  If they've managed 
to get through my anti-spam filters and the message fails the test of 
whether or not the poster is a subscriber to the list, the best thing 
to do is to hold those messages for moderation.  Failing that, the 
next best thing to do is to attempt to notify the sender that the 
message was rejected (making sure to use rate-limiting technology so 
as to avoid excessive joe-job blowback).

	Only as a last resort is it appropriate to simply throw away 
messages that would otherwise have been held for moderation.


	But then maybe you've got different kinds of mailing lists where 
you don't really care about the content and where the posters don't 
really care about the content, and no one is going to get upset if 
some messages get thrown away.

-- 
Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

  LOPSA member since December 2005.  See <http://www.lopsa.org/>.