Squirrelmail is open source webmail software, written in PHP and licensed under the GNU General Public License.

The email.uoa.gr project, which aims for a feature-rich and scalable mail system, is actively contributing code for the Squirrelmail project.

The email.uoa.gr project currently focuses on the following components: Cyrus IMAP, Sendmail, OpenLDAP and Squirrelmail.

Fully Cyrus-IMAP integrated

• Supports Cyrus' IMAP shared folders and has enhanced error handling with regard to ACLs.
• Supports SIEVE server-side mail filtering via the avelsieve plugin.

Fully LDAP enabled

• Gets the user profile (name, email, IMAP host etc.) from LDAP.
• Stores user's webmail preferences on LDAP. [Of course, extensive caching is used for these operations; see the documentation about the ldapuserdata plugin for details].
• Offers a directory service based on LDAP.
• Gets additional information about shared folders and bulletin boards from LDAP. [Apart from Cyrus IMAP's ACLs, various things such as the owner's dn, a description and the folder's post email can be stored in the LDAP server.]

Scalable

Whenever a single webmail machine is not adequate, a new machine can be added very easily. The only thing that must be changed on 'webmail2' should be the IP and the SSL certificate.

Such scalability also applies to other components of the mail system.

User-friendly Posting Control

A special feature of the email solution is the implementation of "mailing lists" or "bulletin boards" as IMAP shared folders.

Squirrelmail's left frame has been modified to display not only these folders, but some information about them as well: mainly, a short textual description of the shared folder / bulletin board, and a small icon to post easily to a folder, provided the user has the appropriate permissions.

This makes for a complete, scalable and, most of all, RFC-defined groupware solution.