PMDF-LAN Overview

The PMDF-LAN family of gateways generally operate by passing container files of mail messages between the PC system and the system running PMDF-MTA. PMDF-LAN is not responsible for moving the container files from one system to the other. A common way for files to be moved between environments is for the system with PMDF to act as a file server for the PC system. In this case PMDF-LAN is configured to read and write files in a directory that is servered to the PC network operating system and a PC is configured to run the import and export software for the PC mail system. While it is common to use a PC network operating system to move files between environments it is by no means required. Any method can be used to transfer files including something as primitative as Kermit.

A primary responsibility of PMDF-LAN is to make sure that all address information is re-written into a format compatible with the destination mail system. In addition, PMDF-LAN will restructure and encode mail messages to make sure that the original content is accessible from the target mail system. For example, while the MIME specification defines message formats that can have a nested structure in an arbitrary fashion, cc:Mail does not support nested mail structures. In this case PMDF-LAN will convert the nested elements of the MIME message into cc:Mail attachments.

Wherever possible PMDF-LAN will respect and preserve the original content and format of a message. When this is not possible because the mapping of the feature set of one mail system to the MIME standard is ambiguous PMDF-LAN provides user definable options. For example, many of the PMDF-LAN mail channel programs allow the specification of the binary encoding method to be used for creating attachments.

In one special case PMDF-LAN will write messages directly into the message store of the PC mail system. When:

  1. The PC mail system is on a Novell NetWare server
  2. and the system where PMDF-MTA and PMDF-LAN are installed also has MultiNet installed

then PMDF-LAN will write directly into the PC's message store using the Novell API provided by MultiNet.

Mail from PMDF to PC

The following steps describe the typical movement of messages from the SMTP backbone into the PC mail system.

  1. The PMDF-MTA system receives mail destined for the PC system and queues the message to the appropriate PMDF-LAN channel.
  2. PMDF-LAN reformats the message into the format that the PC system will accept.
  3. PMDF-LAN writes the reformatted message into a container file.
  4. The container file is transferred to a support PC.
  5. The container file is read by a program running on the support PC that reads the inbound container file and writes into the PC mail systems message store.

Mail from PC to PMDF

The following steps describe the typical movement of messages from the PC mail system to the SMTP backbone.

  1. The export program is run on the support PC. This program reads messages from the PC message store and writes them to a container file.
  2. The container file is transferred to the system running PMDF-MTA and PMDF-LAN.
  3. PMDF-LAN reads container file, creates MIME messages, and queues them for delivery to PMDF-MTA.


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