Here's the link:
http://wiki.exim.org/InformationGathering
Using Exim for Real Time Information Gathering
Exim has a very powerful feature ReadSocket
<
http://wiki.exim.org/ReadSocket> tat allows Exim to send simple TCP/IP
messages. These messages can be accepted and stored for real time data
processing. The idea is that multiple Exim installation that are
processing email could, for example, send black list data to a central
gathering computer. The central gathering computer could update in real
time a blacklist RBL making the blacklist information available to the
world within seconds of minutes after the event occurred. In this
example we'll assume that an Exim server has detected a virus bot and
wants to report the IP address if the virus to a centralized blacklist.
The centralized blacklist is receiving the TCP messages from many
reporters who are all part of a spam fighting group.
The Exim Sending Code
In this example we have Exim servers configured to send simple on line
messages to a central location that is gathering the status of IP
addresses. The message will look like this
black 1.2.3.4
The message is sent using the Exim ReadSocket
<
http://wiki.exim.org/ReadSocket> feature.
set acl_c_socket = ${readsocket{inet:listening-server.com:444}{black $sender_host_address\n}{3s}{}{}}
In the above example the message "black" along with the IP address of
the sender is sent on a single line to the host "listening-server.com"
on port 444. You can of course send any messages you can construct. You
might want to send "white" and an IP address to white list.
The Listening End
The listening end can be any program that accepts connections and does
something with the information. In this simple example we will just take
the data and store it in a file in /tmp/karma.log.
socat -u TCP4-LISTEN:444,reuseaddr,fork OPEN:/tmp/karma.log,creat,append&
This file could be harvested once a minute, for example, and processed
into an RBL. Or you could do something more interesting like update a
MySQL database that is controlling an RBL to make the information
available instantly.
The Purpose
If a coalition of Exim users organized to provide real time data to an
IP or host name based reputation service where all who participated
shared in the results it could become a powerful spam fighting tool.
Exim with its ReadSocket <
http://wiki.exim.org/ReadSocket> command is
very suited for such a project.
