The internal architecture of Carbonio CE, including all of its components.

While in a Single-Server, all packages are placed on the same node, in a typical Multi-Server, each of the services shown by the red boxes should be put on a dedicated node, while the others can be merged and deployed on any node, even a dedicated one. For example, User Management can be placed on the AppServer node rather as a separate node. In the sample scenario, we demonstrate how to configure a cluster of five Nodes and integrate the various Carbonio CE roles. A role is an atomic capability that may be introduced to the Carbonio CE by the installation of one or more software packages.

In Fig. 1, dependencies are represented by boxes stacked on top of one another. In other words, all *-UI packages, which include the files required to display the Module to users, must be installed on the Proxy Node.

The Postgres/DB-Connection role is a specific situation. While Carbonio CE may be installed to connect directly with a Postgres database, it is recommended that a middleware (PgPool-II) be installed to be independent of the underlying database(s) and scalable without the need to configure numerous Postgres instances or even a Postgres cluster.

Supported Mail Protocols

Carbonio CE supports the following protocols.

• POP3, POP3S
• SMTP and its security protocols SSMTP and SPTMS (SMTP over TLS or SSL)
• IMAP and its Secure Protocol IMAPS (IMAP Over SSL)