Introduction
The University of Athens email project is a full email architecture, deployed by the Network Operations Center at the University of Athens to provide email services to all its students and academics. The goal is to deploy a scalable, stable, robust and feature-rich email architecture, based on proven, widely deployed open source software. After researching existing open source email related projects, the most suitable of them were chosen, while some of them had to be modified to suit our needs. However, there were cases that software had to be written from scratch, because no available software suited our needs.
The University of Athens email architecture is aimed at large sites with several thousands of users, where stability, security, extensibility and manageability are key features.
Components
OpenLDAP
A setup with such goals should be based on an LDAP database. LDAP backend is the way to go, because of its extensibility and integration with other software. OpenLDAP server is used for storing user database as well as the system metadata.
Link: http://www.openldap.org
Sendmail SMTP server
The SMTP server of choice is the widely used popular Sendmail. It was chosen, although it is known to be quite complicated and definitely more resource consuming than other open source SMTP servers, because of its breadth of features and its suitability to large sites. Morever, Sendmail's cooperation with LDAP server is exceptional.
Link: http://www.sendmail.org
Cyrus IMAP server
Cyrus IMAP server is the top open source IMAP server. It is fast and secure, it scales to several thousands of users, while delivering key features such as shielded mailboxes, Access Control Lists, virtual domains and server side filters.
Nevertheless, Cyrus has a very poor integration of LDAP services. For this reason additional code had to be written. The extra code added to Cyrus delivers features such as retrieval of group membership from an LDAP backend, improvements in quota management, automatic INBOX creation, dynamic (LDAP attributes based) user permissions and more. Currently most patches apply only to Cyrus 2.1.x versions but patches for Cyrus 2.2.x are under development.
Link: http://cyrusimap.web.cmu.edu - Cyrus patches: http://email.uoa.gr/projects/cyrus
Cyrusmaster
After researching the available open source projects for the administration of Cyrus IMAP server, we concluded that there was no open source tool that could be sufficient for the needs of our mail projects. Basically due to their poor cooperation with an LDAP server. Besides, we needed an administrative environment that could make the most out of our custom modifications to Cyrus.
This resulted in developing our own web environment for administering Cyrus. Cyrusmaster is designed for large sites and is the glue software between Cyrus and the LDAP backend. It offers all the necessary features for creating/modifying/deleting user mailbox, adding/modifying/deleting user objects in LDAP and offers a complete set of tools for managing shared folders creating the infrastructure for an advanced collaboration environment.
Cyrusmaster homepage: http://email.uoa.gr/projects/cyrusmaster
Squirrelmail
Squirrelmail is one of the best open source webmails. It is fast, user friendly, modular, cleanly designed, feature rich and cooperates perfectly with Cyrus IMAP server. More than that, plenty of work has been done on Squirrelmail and a lot of new features have been added, making it even more efficient and productive for our users. Better LDAP integration was a key goal while developing.
Link: http://www.squirrelmail.org - Squirrelmail plugins and patches: http://email.uoa.gr/projects/squirrelmail
Release Information
All software component sources, patches and necessary documentation will be released to the public with the appropriate open source license.