--On 9 February 2007 01:38:22 +0100 Magnus Holmgren 
<[EMAIL PROTECTED]> wrote:

> On Friday 09 February 2007 01:10, Tiago T. Adloff wrote:
>> I wanna know if there is some kind of filter in exim or addon, that can
>> blocks a sending when the limit of "to" and/or "cc" addresses exceed a
>> certain number predetermined.
>>
>> With this I can stop spammers clients using my MTA.
>
> Stop spammers from spamming you, or stop your users from spamming others?
> You  aren't letting spammers use your server as an open relay, are you?
>
> You might be interested in the ratelimit ACL condition:
>
> http://www.exim.org/exim-html-4.66/doc/html/spec_html/ch40.html#SECTratel
> imiting
>
> If you want to limit the number of recipients per mail or the number of
> mails  per connection, there are simpler ways.

search for "rcpt_count" in the docs 
<http://www.exim.org/exim-pdf-4.66/doc/spec.pdf>, and understand that an 
email without either To: or Cc: headers can have thousands of Bcc 
recipients. Alternatively, an email with thousands of addresses in the To: 
header might actually have only one recipient. See 
<https://helpdesk.islandnet.com/pep/smtp.php>, for example.



>  I don't suppose you mean
> that you  want to limit the number of apparent recipients in the To: and
> Cc: header  fields. :-)

He might do. That's something I'm trying to implement here, after a very 
nasty internal spam attack. Someone emailed all students on campus, and 
included 20,000 email addresses in the To: header. 70 people hit 
reply-to-all.

What I'm trying to do, if I can get the syntax right, is replace long 
headers To: and Cc: headers (say, more than 1024 chars) with a comment like 
"long list hidden by postmaster:;". I don't see a way of actually counting 
the number of addresses, which I'd slightly prefer.


-- 
Ian Eiloart
IT Services, University of Sussex

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