Sympa is a rich open source mailing list software. Its design highly focuses on customization possibilities and ease of administration. Advanced features: – Bulk emailer – Internationalization, translated to 15 different languages – Service messages and web pages defined by templates Subscriber information stored in a RDBMS (Mysql, Pg, Oracle or Sybase) – Web interface with user and admin features – Different web authentication backends including Single Sign-on systems – Web document repository for list members – S/MIME support for both signature verification and mail encryption – Automatic bounces management – External antiviral plugin – Virtual robots management – SOAP ML service Dynamic mailing lists The standard way to build mailing lists is for members to subscribe to the list, though the list owner may sometimes add members (for working groups mailing lists). Sympa proposes another way to build more administrative mailing lists in relation with your information system. This kind of institutional mailing list can range from small working groups allowing horizontal communication to a newsletter for contacting all employees. Informations regarding these populations are either stored in a relational database or in the institution’s LDAP directory. Sympa has the ability to dynamically build mailing lists based on RDBMS (many supported databases) and LDAP directories. Interfaces to the mailing list service Sympa mail interface is comparable to other well known mailing list softwares. Commands (subscribe, review, lists,…) are sent to an email address unique for each virtual robot. Each mailing list has a main address for sending messages and associated administative addresses (-request, -owner, -unsubscribe,…). Like most mailing list servers, Sympa provides a web interface to the mailing list service. All mail features are available (archives, subscription, members review,…) and even more (document repository, list creation and setup, template customization,…). User authentication is password or certificate based, privileges for each operation are evaluated by an authorization engine. All web pages are defined by templates that have been internationalized (14 languages) and can be customized by listmasters. A SOAP server for Sympa has recently been added to the package. This server provides an API to integrate simple mailing list services within another application ; for example include a list subscription form in a PHP page. In the past, external applications would directly access Sympa’s database, thus bypassing Sympa’s authentication and authorization procedures. The SOAP interface makes it easy to develop a Sympa Uportal channel; this has been done by the french ESUP project, along with CAS authentication. A hierarchical organization Sympa is designed as an engine to manage a large number of mailing lists built on top of a common base, not just mailing lists side by side. This architecture allows a global management of virtual mailing list servers under control of different listmasters, each of them managing a set of mailing lists. Like Apache’s virtual host concept, Sympa can manage multiple mailing list services (called Virtual robots) within a single installation. Virtual robots share the same code and a set of configuration files (including web templates and authorization scenarios), thereby requiring only specific parameters to be customized at the virtual robot level. The same inheritance principles apply to mailing lists themselves, thus making their configuration lighter. A single web interface allows a global management of user preferences (language, preferred MIME format,…) as well as the authentication service. Sympa also provides transverse features such as list memberships for subscribers and the ability to manage mailing lists and users for the listmaster. Hosting of large mailing lists (can cope with 100.000 subscribers) has lead us toward a fine-grained and strict definition of roles in Sympa, because responsibilities and administration tasks need to be shared. From the higher to the lower level Sympa defines the following roles : the super listmaster, the virtual robot listmaster, the mailing list owner, the mailing list moderator and the mailing list subscriber. The super listmaster is responsible for creating new virtual robots and defines default global parameters inherited by virtual robots, whereas the listmaster’s main task is mailing list activation. List owners are in charge of subscribers management (subscriptions requests, bounces) as well as list setup (access control to each feature). One list owner is responsible for delegating administration tasks to a group of list owners, if the mailing list size requires such an organization. List moderators (who are often also defined as owners) are responsible for editorial contents of moderated mailing lists.