Open source brings a spam-free lunch

David M Williams
Monday, 14 January 2008 06:22

Opinion and Analysis

ASSPSMTP
The Anti-Spam SMTP Proxy (ASSP) server project is a free open-source platform-independent transparent SMTP proxy server. This is a mouthful, but essentially means, as described above, that it sits in between the Internet and your mail server. It is hosted on SourceForge http://www.sourceforge.net and can be downloaded there.

Although the project is called ASSP, it is commonly referred to as ASSPSMTP so grammatical purists will need to overlook the redundant “SMTP” in the acronym.
ASSPSMTP’s requirements are quite low; a server must have about 700Mb disk space and permit outbound queries on port 80 (Web) and port 53 (DNS), and finally, must support Perl 5.8 or later. ASSPSMTP has been written in Perl and so long as a Perl interpreter is available (and a couple of Perl modules have been installed) for your operating system there are no other considerations whatsoever. Windows users can use ActivePerl. An optional Perl plug in (ClamAV) lets you add anti-virus scanning to the existing anti-spam facilities.

Only a few configuration items need to be set; one is the web-based administration password and it is important you do this quickly because the default password is well-known (“nospam4me”). Another very important setting is the local domain name, or names, that you expect to receive mail for – without this, ASSPSMTP will interpret inbound mail as relay attempts.

Once the package has been installed and executed, open a web browser and navigate to http://127.0.0.1:55555. This is the web admin interface for ASSPSMTP. Login with a blank username and the default password as above. You can now fully configure all the actions and behaviours of ASSPSMTP. It’s imperative you tell it the location of your mail server or else for all the good ASSPSMTP does, your mail will never reach you!

Your mail server can be running on another box entirely, or it can be on the same server as ASSPSMTP itself; in that case, you ought to set the “real” mail server to listen on a different port than port 25. ASSPSMTP will receive the incoming mail on that port, not your mail server.

The current release of ASSPSMTP is 1.3.3.8, released on the 16th of October 2007. You can download it from the download page as well as find some other very useful tools to complement the product. One of these is ASSPR, Anti-Spam Server Proxy Report, which is a small C program to report on the amount of spam caught by ASSPSMTP and can make informative reading.

So that’s just two high quality FOSS products for fighting spam; they’re both robust, they’re both scalable and high-powered, and they’re available for use right now without complex licensing arrangements.

Who said there was no such thing as a free lunch? This lunch is served without spam.