Re: [Exim] `filtering' outgoing mails

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Author: Suresh Ramasubramanian
Date:  
To: exim-users
New-Topics: [Exim] mysql error
Subject: Re: [Exim] `filtering' outgoing mails
Tamas TEVESZ rearranged electrons thusly:

> think could help reduce the problem (no, the classical baseball
> bat-based solution simply doesn't work): what if i could somehow tell


Use a wooden mallet instead. It produces far more thorough results than a
baseball bat :)

> identify a message, and if the rate for message/recipient goes over a
> specified threshold, then exim would just silently discard the
> messages (rejecting them, queueing them, freezing them and anything


Can be done (we used to do it at my former employer - Juno - but with an
inhouse developed MTA, not exim). However, it's advisable to send a mail back
to the user saying that the mail has gone over a threshold and so has been
dropped (common courtesy and all that <g>). And put a note to that effect in
your terms of service.

Or else, what you are likely to face (not as often as spam) is that some user
sends a wedding invitation (or something) to a couple hundred of his friends
... the bitching that results if you drop such mail on the floor - _even_ after
sending back a mail pointing out the relevant part of your ToS - has to be seen
to be believed. :)

> i'm now at writing some perl code to achieve that (haven't yet managed
> to get far, though). my question is kindof twofold: is it doable at


I'd suggest that, along with all this, you provide a bank of commonly available
cgi scripts to your users - and specify that any custom cgi scripts which have
to be installed must be vetted by your staff first. This saves you the problem
of badly written perl scripts bogging your server down, as well as the
possiblity of rogue cgi scripts (spamware, portscanners etc).

Also, arrange to run the cgi scripts under the user's id (instead of some
totally anonymous id like nobody / www etc) if possible.

    -s


--
Suresh Ramasubramanian <--> mallet <at> efn <dot> org
EMail Sturmbannfuhrer, Lower Middle Class Unix Sysadmin
"What separates normal people from kooks is how they react when people disagree
with them or tell them "NO" <-- Ron Ritzman on news.admin.net-abuse.email