Too Much Spam? CanIT!

eLABorations: Open-source software has a message for junk mailers: Return to sender

I recently came across a promising anti-Spam solution called CanIT, from Roaring Penguin Software, an open-source software company based in Ottawa. My preliminary tests showed CanIT could be the answer for sites looking for a low-cost Spam filtering solution.

CanIT, server-based software that supports Linux and Unix OSes, uses SendMail to relay mail to industry-standard e-mail systems such as Microsoft Exchange or Lotus Domino. CanIT is based on MIMEDefang, a program written in Perl that inspects and modifies e-mail messages as they pass through the SendMail relay.

Interestingly, besides keeping junk mail and viruses out of end users mailboxes, CanIT can refuse junk mail at its source, thus keeping Spam on the senders servers.

CanIT acts as a spam trap by screening out unsolicited messages using filtering rules and a weighting algorithm. Since CanIT refuses all e-mail identified as junk before it reaches a companys e-mail servers and end users, CanIT can keep unsolicited e-mail where it belongs—at the server of origin.

Of course, CanIT is not 100 percent foolproof, and questionable messages occasionally require an administrator to make the final decision. CanITs user interface allows administrators to check false positives: if a message deemed spam attempts to enter the system a second time, it gets refused with a permanent failure indication.

CanIT software will scale based on the hardware on which it is installed, so companies can use clustered systems or high-end Unix servers to handle high-volume e-mail streams.

The fact that CanIT is an open-source program means that it is less expensive than other e-mail filter plug-ins or appliances. Companies can either license CanIT on an annual subscription plan, or purchase it directly. In both cases, prices depend on the number of mailboxes protected. The direct purchase price is $12 per mailbox with volume discounts available. Annual license fees start at $4 per mailbox with volume discounts.

For sites that dont have Linux or Unix systems, or dont have IT expertise, CanIT is also available as an appliance (prices vary depending on the size of the site). The CanIT appliance comes pre-installed with all the software required; it starts doing its job once its installed in front of existing e-mail servers.

Technical Analyst Francis Chu can be reached at