A question that is often asked about commercial software on the Linux platform is "why should I pay for something when I can get it for free?"

That's a pretty good question, actually, and it's certainly one that came up at the Stalker Software booth when the company first started showing up at LinuxWorld Expo. Visitors to their booth would look at the firm's flagship product, the messaging server CommuniGate Pro, and frequently ask that question. Sendmail, after all, could do much of the same thing for a whole lot less in cost.

Stalker must be doing something right, because despite this price-point hesitancy, Linux sales make up the majority of their revenue stream, over and above sales on the Windows and OS X platforms.

Last week, Stalker released another iteration of CommuniGate Pro, version 4.1, which brings more collaborative and messaging tools to the Linux platform.

CommuniGate's niche fits within two specific verticals: small- to medium-sized businesses, which make up 80 percent of the product's installation base, and then telecommunication and ISP companies.

Phillip Slater, a sales engineer with Stalker, sees the appeal of CommunGate Pro for Windows users who want to switch away from Exchange. In fact, he explained, many new users will use the opportunity of the Exchange migration to move all the way from Microsoft and fully convert running CommuniGate Pro on Linux instead.

CommuniGate Pro 4.1 is pushing two new features: a groupware function that more efficiently integrates with Microsoft Outlook clients, something many Linux admins might be faced with; and a Web-based messaging system that will let people access their messages regardless of what plafrom they're coming from.

Besides Outlook, CommuniGate Pro supports standards-based mail clients such as Eudora and Netscape and clients like Evolution that adhere to e-mail and calendaring standards.

The software can support tens of thousands of enterprise users on a single server, which reduces infrastructure costs.

"CommuniGate Pro 4.1 with Groupware is the ideal solution for enterprise and education users looking to increase productivity by managing appointments and tasks, collaborating on projects, and sharing contacts from their office or on the road," said Vladimir Butenko, president and CEO of Stalker Software.

Stalker's customers seem pretty pleased with the software's performance thus far.

"We chose CommuniGate Pro 4.1 because it offers all of the features we want, wrapped into a reliable and easily managed messaging solution," said Jason Mader, manager of information technology, FHWA/NHTSA National Crash Analysis Center and The George Washington University, Virginia Campus. "The simple setup and encryption for supported protocols make it easy for everyone on campus to access their e-mail securely, over the University network and over the Internet."

CommuniGate Pro 4.1 runs on over 30 OS/hardware combinations, including Linux, UNIX, Windows, Mac OS X, and AS/400. Slater emphasized that all of the CommuniGate flavors come from the same software code, and is compiled individually for each platform.

"You should see our server room," he chuckled, "It's a real zoo with all of those platforms."

Stalker sees its viabaility as a messsaging server over venerable favorites such as Sendmail because their software comes with a lot of commecial level support. Sendmail support, Slater explained, is almost always local--usually a Sendmail guru. If the guru ever leaves the company or goes on vacation, then if something goes amiss, there could be real problems.

Stalker, he added, provides full remote administration capabilities for all of the CommuniGate Pro platforms. So if the local mail administrator takes an extended break, it's a simple matter for another administrator in the company or even from Stalker to step in if need be.

With the relase of its new version 4.1, CommuniGate Pro joins the growing list of messaging alternatives for the Linux platform.