Re: [Exim] Bulk Mail

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Author: Jeffrey Goldberg
Date:  
To: Sujit Choudhury
CC: exim_users
Subject: Re: [Exim] Bulk Mail
On Fri, 16 Mar 2001, Sujit Choudhury wrote:

> In our future set up, we would like to prevent (if possible) bulk mail or
> junk mail from outside
> our domain.


The exim documentation has an entire chapter on policy controls.

> I know there are batch_max and smtp_accept_max_per_host options
> available. However, in our case the staff (about 1000) have their own
> mail server and all their incoming and outgoing E-Mails would use the
> mail hub. Setting these options may affect the performance of the
> staff server.


Those tools are not really the best way to achive spam control (although
they can play some role). They can also interfere with legitimate mailing
lists many of your users are on. Spammers have learned to send things in
batches of < 100, so these really won't do too much against spam.

Generally, make good use of the RBLs. (By the way all, someone from MAPS
told me that the preferred usage is for "RBL" to apply to the MAPS RBL
only and for other lists using the same mechanism to use DNSBL (DNS Based
Lists).

Using MAPS, DUL, and RSS will be the single (three) things you can do that
will prevent most incoming spam. Using MAPS is fairly uncontroversial.
Using the other two is controversial for seperate reasons we don't need to
get this list into again. Check them out, and make an informed choice
yourself. Though, I suspect that by now RSS should be almost as
uncontroversial as MAPS.

You MAY wish to set up a system filter that freezes suspected spam based
on various parameters. I personally oppose such things (unless you
follow-up each spam with a complaint to the appropriate places), but that
again leads to discussion we really don't need to get into here.

The use of callbacks to check things out about the site mail is coming
from is not something that I have used, but it allows for even more
sophisticated blocking. Again, read the relevant chapters in the exim
specification.

> I would be interested what other places have done (or intend to do) to
> stop the bulk e-mailing.


> University of North London


You might want to check out the uk-mail-managers list which is primarily
for .ac.uk sites and people do spend a lot of time sharing and discussing
their policy decisions. I don't have an exact pointer to that list handy,
but if you hunt around for it, I'm sure that you will find it.

-j

--
Jeffrey Goldberg
I have recently moved, see http://www.goldmark.org/jeff/contact.html
Relativism is the triumph of authority over truth, convention over justice