HORDE IMP Webmail Client Version 4.0.1 review

MP stands for internet messaging program, and its a webmail program that lets you add a web interface to your POP3 or IMAP email system.

It runs on top of Horde, a system that supports PHP applications. IMP is one of these, but there are others including a contacts management program called Turba, a diary, task manager and a bookmark organiser.

IMP is one of the most popular webmail packages available. It's compatible with any IMAP mail server, and an administrator has to make only minimal configuration changes to add it to an existing mail system, as you don't need to set up any extra user accounts.

IMP integrates well with the rest of the Horde suite, using modules to add features. The most popular of these modules is Turba, a contact management application that can use an SQL database to store information.

IMP is one of the most feature-packed IMAP clients we have seen, including programs such as Outlook and Evolution. Although it's web-based, its list of features is extensive and includes filters, folders and even support for PGP encryption. It rivals Microsoft's Exchange and has been deployed by some of America's top companies in the Fortune 500 list, as well as smaller organisations. Some of these systems support over 40,000 users using various clustering techniques.

Installing Horde and IMP is fairly painless and the documentation for both is very detailed and accurate. As both projects are very actively developed there are a large number of people on the mailing lists who are happy to help should you have a problem. You need at least a functioning IMAP or POP3 server, which can be on the same computer but needn't be, and also a MySQL database to hold user configuration and address book information. It can be extended to use other protocols, such as LDAP for address books.

Although it's a fairly complex application, IMP is surprisingly easy to use. The options section that the user sees is laid out nicely and is simple enough for novices to use and powerful enough for professionals. The options are plentiful and well explained. IMP can perform tasks such as automatically checking for new mail, fetching mail from other mail accounts and alerting you with pop-ups when you are logged in. The most useful feature is the mail filter. This has much the same rules as those you'll find in Outlook, and they perform the same functions such as moving mail received from friends to a specific folder, or deleting spam outright before you see it.

The MIME handling is very good. Messages are displayed in text format rather than HTML by default, but a link to the HTML alternative is included and shows the HTML in a pop-up window when clicked, making it easier to read. We couldn't find an option to make it display HTML by default, which would be a welcome addition.

Attachments are also handled very well, with both a link to an inline viewer and a link to download or save the files. It means, for example, that you don't have to save an image to disk before viewing it, although you can if you wish.

Users compose messages in a pop-up window, and a fairly feature-packed HTML WYSIWYG editor is available as an option. A spellchecker is also included, although this doesn't check your spelling as you type. A very nice touch is the Special Characters button, which allows you to use a selection of accents on your letters for writing in foreign languages if you do not have these on your keyboard.

IMP is well written, feature-packed, and easy to use and, when used alongside other Horde modules, can form a very serious business system or just a handy personal webmail site.