----- Original Message ----- 
From: "Rick Davidson" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, June 21, 2004 11:09
Subject: Re: [IMail Forum] Dictionary Attacks and MX Records


> dunno if this will help but here is a perl script I use to count ip
> addresses in the imail sysXXXX.txt files, its quick and dirty but will
give
> you a list of ip addresses that connected to your server and how many
times.
> I run the command line from a bat file for ease of use. The draw back is
> that dictionary attacks are often done with spam zombies which could keep
> you busy greppin for a long time.

I have a script written in VBS which imports the ERR rejections in the
logfile to a MySQL table, dividing everything into 288 five-minute segments
(for a total of 24 hours).  With these hopefully I can start determining the
frequency with which something attacks.  As I said, the trick is determining
the trigger for a dictionary onslaught, and determining how long an IP
address should remain blocked.  I certainly do not want a permanent blocked
senders list, but I want to cripple IPs that are pushing through dozens of a
messages a day, and possibly hundreds a week.  The other problem is size.  I
can envision such a database hitting hundreds of thousands of addresses to
even see a significant drop, and now we're probably pushing to the point
where IMail's access control system will become a big problem.

-- 
A. Clausen
[EMAIL PROTECTED]


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