As a free, open-source solution, IMP Webmail has been around since 1998, giving ISPs an enormous amount of flexibility in maintaining a webmail offering.

by Jeff Goldman [August 18, 2004]

Chuck Hagenbuch created IMP Webmail back in 1998 while he was studying at Williams College in Massachusetts. The student computing organization at the time provided a range of services that weren't available from the college itself—and when Hotmail first appeared, Hagenbuch says, the organization decided to create its own webmail solution as an alternative.

As more and more developers worked with IMP, Hagenbuch says, its functionality grew beyond webmail. That larger Web framework became what is now Horde, an entity that has become increasingly independent over the past few years. "The version that we have in alpha is a complete, standalone Web framework," he says.

IMP Webmail

Horde now includes a number of different projects, ranging from calendar, contact, notes, and task managers to tools for everything from e-mail forwarding to filtering. "There's something like 40 or 45 applications now," Hagenbuch says.

The proof of Horde's current robustness, Hagenbuch says, is the fact that there are now developers working on Horde who don't work with IMP at all. "They may end up using it because they have Horde installed, but there are people whose entire application focus is elsewhere," he says. "Before, if you were using Horde, you were using it because of IMP."

Building on infrastructure
Hagenbuch says IMP Webmail is a particularly attractive solution for universities and ISPs. "The people who tend to use IMP are people that have an infrastructure," he says. "They have a set of servers, they provide services to a wide user base, and they want to offer webmail to those users."

If an ISP is using CommuniGate Pro or any similar commercial solution, Hagenbuch admits, they're unlikely to need something like IMP Webmail. But if they're building their own set of components, IMP can be an attractive option—particularly since it works well with an ISP's existing architecture. "People can drop it in, it'll talk to their existing cluster of IMAP servers, and it'll do whatever the existing desktop client that they already support does," he says.

The solution will work with just about any operating system an ISP might want to use. "I do development on my iBook, which runs OS X," Hagenbuch says. "It certainly runs on pretty much any UNIX server, and it'll run on Windows as well. PHP in general—and the whole environment—will be much happier if you run it on a Windows version of Apache than if you run it on IIS, but people have run it on IIS."

Spam and virus filtering
The current release of IMP, the 3.x series, has basic client-side filters, but the next release will work directly with spam and virus filters. "With IMP 4.0 and the series of applications that work with it, there is a front end for preferences for SpamAssassin and amavisd-new," Hagenbuch says. "So you can set your filtering thresholds for spam and virus filtering, and you can set whitelists and blacklists."

That functionality isn't available in the current stable release, but there are ways to access it before IMP 4.0 is released. "There are a number of people running the current CVS code at this point, and there are nightly snapshots available as well," Hagenbuch says.

A hands-on approach
IMP Webmail isn't likely to be an appropriate solution for a novice. "It's not something that's a breeze to install if you have no idea what an IMAP server is," Hagenbuch says. "We get questions on the mailing lists from people who are confused about the idea of a mail chain, the MTA and the IMAP or POP server, and how it all fits together."

Still, for people who do have an understanding of the structure of a mail system, IMP can be an ideal solution. "I think it does appeal to people who want a hands-on approach, because you can configure pretty much every aspect of how it talks to the IMAP server, where it stores its data—all of that," Hagenbuch says.

As an open-source solution, IMP is available for free. If an ISP needs help with specific aspects of the installation, consulting is available. Support is usually handled using the Horde mailing lists—no ongoing support contracts are currently offered. "That's something that some of the developers talk about now and then," Hagenbuch says. "It might happen down the road."

The advantage of working with an open source application, of course, is its flexibility. "People tie IMP into their own systems, or they tie the other applications into custom applications," Hagenbuch says. "I'd say it's a pretty good proof of the framework that we've been able to build all these different applications on it. For a simple application—and if you know the framework—it takes about a day's work to get a new application going."

— End

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