Atmail is a fully-featured email server and Webmail client, allowing users to send and receive email via a Web browser or mobile device. It has full support for IMAP mailboxes, and an optional email-server mode that uses EXIM as the MTA. Features include a scheduler, MySQL backend support, spell-check, address book, calendar user preferences, multiple accounts, SpamAssassin support, migration scripts from other mail servers, a customizable interface, an attractive AJAX interface, an optional group sharing Calendar/Addressbook, and an Outlook plugin to sync Contacts/Tasks/Calendar data between a Desktop, Mobile, and Webmail client or other email users.
Forwards is a Horde module for setting user e-mail forwards via the .forward mechanism supported by several popular mailers. Forwards provides fairly complete support for setting .forward style forwards on Sendmail, Courier, or Qmail based systems via an FTP transport. It also has drivers for Mdaemon, Exim SQL, Exim LDAP, Custom SQL, and SOAP based systems.
MIMP is a version of the popular webmail client IMP intended for mobile phones and PDAs. Basic webmail functionality is implemented, including mailbox viewing and paging, viewing messages, deleting, replying, forwarding, and composing new messages. It utilizes the Horde Application Framework.
Openmailadmin is a little administration interface to every complete IMAP mail server daemon. It supports every feature IMAP provides, and fits in most MTA configurations. A key feature is the non-standard, generic administration hierarchy which not only seperates "normal users" from "administrators", but enables the mailserver-master to create instances between them. You will be able to let other users create their own sub-users and thus either share a single mail server between different organizations or project your company's employee structure. It excels with features such as regex addresses and folder ACL management.
ezmlm-idx is an addition and patch to ezmlm, adding multi-message threaded archive retrieval, digests, remote administration, message and subscription moderation, subscriber-only restrictions, message trailer, subject prefix, subscriber name storage, customizable setup, multi-language and MIME support, and more. In addition, it has improved bounce handling, case-insensitive subscriber address storage, and support for distributed lists (main and sublist are transparent to the subscriber). It can be compiled with MySQL or PostgreSQL support.