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Internet Exchange Frequently Asked Questions

Internet Exchange Messaging Server
Mailsort FAQ

Introduction
The Internet Exchange Mailsort Utility (both Enterprise and Workgroup versions) is used for defining rules so that the local mail delivery agent can direct messages to preselected mailboxes/folders other than the INBOX.   It can also selectively forward messages to other Internet email addresses.   This feature enables users to sort incoming mail based on attributes such as the message sender and subject without having to go through all the messages individually.   For example, a user may want to store messages in folders according to sender or subject line.  This can easily be done in Internet Exchange using the MailSort utility.  The sorting actions are done in the background by the server at message delivery time, and are transparent to the users.

Technical Overview
MailSort is divided into two modules, the engine and the web interface.  The engine is use by the Local Mail Delivery Agent to determine the destination of messages whose recipients maintain filtering information in their respective Message Store directories.  The web-based interface allows the users to create and edit filter files used by the engine to inform the Local Mail Delivery Agent of the destination of the messages.

The Internet Exchange MailSort Module provides users with a utility for preprocessing incoming email on a per user basis.  Incoming messages that will be delivered to the Message Store through the Local Mail Delivery Agent will be sorted according to the rules set by the user via the web-based interface.  The engine will read the filter file (filter.txt), and perform a ver simple recursive-decent parsing to speed up the interpretation of the filter file.

The recursive-decent parsing scheme is divided into two stops, scanning or lexical analysis and parsing.  The engine uses a lexical analyzer on the filter file to divide the file input into meaningful units.   A parser is used to determine the relationship among these units.  For this kind of input, the units would probably be lines of text, with a distinction between lines that contain a match of the target strings and the lines that do not.  The division into units, which are usually called tokens, is known as lexical analysis.  The token descriptions are regular expressions that are used by the lexical analyzer to scan the input text.   As the input is divided into tokens, the parser establishes the relationships among them.  This task is known as parsing and the list of rules that define the relationships is a grammar.  The parser automatically detects whenever a sequence of input tokens matches one of the rules in the grammar and also detects a syntax error whenever its input does not match any of the rules.

Sorting Incoming Messages
MailSort has several options for sorting incoming messages:

  • Move To Folder
    This command tells the local mail delivery agent to deliver the message to the designated mailbox folder of the recipient as configured in the web-based interface.

  • Copy To Folder
    This command tells the local mail delivery agent to deliver the message to the INBOX of the recipient and deliver a copy of the message to a designated mailbox folder as configured in the web-based interface.

  • Reject Incoming Messages
    This command tells the local mail delivery agent to reject the message by not delivering it to its designated mailboxes.

Automatic Responses
MailSort has several automatic responses that can be configured, including:

  • Forward To Predefined Email Address
    This command tells the local mail delivery agent to forward the message to an email address(es) specified by the message's recipient via the web-based interface.

  • Vacation Utility
    This command tells the local mail delivery agent to automatically send a specified reply message to all incoming email messages if configured by the recipient.  For example, a user who is on vacation may have no access to his/her email for a week.   He/she can configure MailSort to send replies to all incoming messages for that period, informing the message senders that he/she is on vacation.

 

Additional Documentation
Further information related to the Internet Exchange Mailsort can be found in the following documents: