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Internet Exchange Frequently Asked Questions

Internet Exchange Messaging Server
Architectural Overview

Introduction
The Internet Exchange Message Store is an IMAP4 optimized dedicated mail repository for storing, retrieving, and manipulating messages.  In addition, the Message Store enables users to access their mailboxes via POP3 and/or IMAP4 capable mail clients, such as Microsoft Outlook and Eudora.

The Message Store is made up of several internal databases.    Access to these databases is carried out via the Message Store API.    The databases are:

  • Users Database

  • Shared Mailboxes Database

  • Mailbox Database

  • Message Status Database

  • Message Envelope Database

  • Message Body Database

The Users Database contains the name, password, and home directory of all valid users.  It also contains a list of the names of the shared mailboxes available to a particular user.  The Shared Mailboxes Database stores the names and home directories of all shared mailboxes in the system, while the Mailbox Database holds information regarding the status of different mailboxes, including the shared mailboxes.  IMAP4-related attributes and RFC822 header information are stored in the Message Body Database and Message Envelope Database, respectively.  The Message Body Database stores the body structure of all messages in a given mailbox.  Access to the different databases in the Message Store is carried out via the Message Store API.

Aside from containing multiple internal databases, the Message Store also includes both the IMAP4 and POP3 servers.  Each of these servers is capable of creating multiple threads to support simultaneous access of the Message Store and the retrieval of multiple messages.

Another Message Store module is MailSort, Internet Exchange's filtering utility.  It delivers messages to specific mailboxes/folders and/or forward messages based on the mail filtering rules defined by the user.  If no filtering rules are defined for the user, the messages are forwarded directly to his/her INBOX.

The Local Mail Delivery Agent is responsible for the delifvery of messages from the Internet to the Message Store.   The Local Mail Delivery Agent also communicates with the MailSort engine to customize the delivery of messages based on user defined rules.