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Article: 1820
From: Lewis Bergman
Date: 2007-12-23 10:32:03 -0500
Subject: milter-limit and limiting rcpts per message

Removal...........: milters-request@milter.info?subject=remove
More information..: http://www.milter.info/#Support
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I found this post from 2005 which discusses pretty much what I am
looking for: 
http://www.snert.com/Software/ecartis/index.php?go=/milters/2005-08/702

I'll post why I would like to limit rcpts per message in milter-limit
(or another milter) rather than in sendmail with:
define(`confMAX_RCPTS_PER_MESSAGE', 50) or some other number.

1. I already use the above. The issue is this. We are moving all
outbound mail to an smtp-auth only system (yea, I know I am late). I
would like to have the ability to do the following:
milter-limit-connect:		5r
milter-limit-Auth:		100r
milter-limit-connect:12.3.45.6  250r

or something like that. This way, I could limit unauthenticated users to
5 recipients per message, auth users to 100, and the specified ip to 250
(since he justified his need and uses auth). If the unauthenticated user
calls in after the error we can easily move him to auth.

2. It is difficult to assign a single limit on all our users. One size
never fits all and the capability would make things easier for our users
and would be much easier for us to customize for someone with a valid
need. Our current setting helps limit outgoing spam (the reason for the
setting) but it does hinder legitimate users to some extent and in my
opinion, letting a spammer send 50 messages before getting an error is
to much.

3. The only real alternative to the above is setting up a listserve for
each person that has a valid need and teach them how to use it. I am not
looking forward to that.

4. I believe that this enhancement, as well as other milters we already
use would help MTA operators to more easily do two things:

a. Move more rapidly to smtp-auth (helping to reduce spam)
b. Place reasonable limits on all users with the ability to have
exemptions when required.

By the way, We use Barricade (smtpf) and it is simply awesome.
milter-limit and milter-error have really helped us to limit the impact
our users have on the rest of the internet as well.

On a side note, are there a set of recommended milters to run on an
outgoing mail server only that have proved to limit outbound spam yet
have a minimal impact on responsible users? 


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