SpamAssassin proves to be an effective engine for battling spam

Groups of users can have designated administrators and different rule sets for filtering. This is a nice feature for supporting groups that receive different kinds of e-mail. For example, marketing can have higher thresholds for marketing-related messages, while engineering can cut them back to none. This granularity can extend to individual users and there are preset configurations for basic users, as well as a full interface for more sophisticated users.

Free IT resource Virtualization Insights from Top Experts - Learn how virtualization gets real! Sponsored by Dell Free IT resource TechNet: More ways to know it, share it, and keep it running. Sponsored by Microsoft

Creating whitelists to ensure that mail from selected sources always gets through is simple and can be delegated as far down the chain as desired, to designated administrators or end-users.

One of CanIt-Pro’s interesting features: The software can be configured to simply not accept mail that appears to be spam. This is unusual; most programs accept the mail and then quarantine or delete it. By preventing the message from being delivered at all, CanIt-Pro can reduce the amount of traffic your mail server must handle. The drawback, of course, is that there’s no way to retrieve false positives. This filtering rule can be disabled, fortunately.

As with SpamAssassin, you can configure rules any way you desire, as long as you can program in Perl well enough to modify the existing rules. Most users will not need to do any programming, but the option does provide for a very open-ended solution. Roaring Penguin supplies full source code and permission to modify it for internal use.

CanIt-Pro can also provide content filtering to ensure compliance with corporate policies by removing incoming or outgoing messages with adult content, prohibited language, or attachments. Further, it provides encryption services.

Performance was within the range that most administrators and users will be satisfied with. In my tests, it caught 90 percent of all spam and had a low false-positive rate of .82 percent.

CanIt-Pro requires less configuration than SpamAssassin but more than MailPoint. It will yield a very flexible, inexpensive enterprise-oriented system that supports thousands of users.

Digitalinfo Networks MailPoint 3000

The MailPoint 3000 appliance proved the easiest to set up and configure in my tests, but it’s the least flexible and lacks some features that administrators at larger enterprises might want.

Priced at $1,599, this 1U, rack-mounted server will handle thousands of users. The price is substantially lower than that of other appliances I’ve tested, and the performance was good, with more than 90 percent of spam filtered and no critical false positives.

Companies seeking a spam-busting appliance with more enterprise features might consider the MailPoint 5000, which is still a good value at $3,499.

Installing the MailPoint 3000 is a simple matter requiring a serial terminal connection for the initial network configuration and an SSL browser connection for the remaining configuration.

The interface is straightforward, and I was able to configure the system without referring to the documentation. Initial spam-filtering performance was lower, as the threshold was initially set to ensure no false positives. Decreasing the threshold, easily accomplished via the Web interface, increased spam-filtering performance substantially without adding false positives.

The MailPoint 3000 adds a GUI to the SpamAssassin engine, giving administrators access to its content-filtering and attachment-blocking capabilities. MailPoint admins can’t adjust Perl scripts to change filtering rules, but the options presented through the interface should prove adequate for most users.

Rather than providing multiple configurations for different domains, groups, and users, all settings on the MailPoint 3000 apply to all users and domains. There is also no provision for individual user access to the quarantine. (The MailPoint 5000 model adds support for multiple user and group configurations.) Although releasing quarantined messages and whitelisting senders’ addresses are easy, an administrator will have to perform those tasks.

Considering the capability you get for the price, administrators who are looking for basic functionality and who are willing to handle quarantines themselves should consider the MailPoint series.

Each of these solutions will have a place in some organizations. SpamAssassin will suit administrators willing to spend the time getting familiar with the documentation and tuning the product. CanIt-Pro is a package that provides a straightforward install and powerful customization capabilities, as well as enterprise-level features for handling multiple groups and users. The MailPoint 3000 is not only easy to install but also simpler to configure, making it useful to even inexperienced admins.