PMDF System Manager's Guide
PMDF-REF-6.0

As the SNADS world is effectively limited to eight character by eight character addressing, while the RFC 822 world has arbitrarily long usernames and domain names, the issue of address transformations must be addressed, particularly how to represent RFC 822 addresses within the SNADS world. There are four general approaches which may be used with PMDF-XGS singly or in combination.

• PMDF can be (and generally is) configured to convert specified short form host names into fully qualified domain names. Thus if an RFC 822 address uses no more than eight characters in the user name and no more that eight characters in the host name part of the domain name, then a natural setup is to simply represent the RFC 822 address on the SNADS side in truncated form, with merely the user name and host name.
• PMDF can be configured to use pseudodomain aliases for specified RFC 822 domain names, e.g., "comp" for "complicated.subdivision.com". Or if long usernames are an issue, PMDF can be configured to look up short aliases in a database or databases to be transformed into actual long addresses.
• PMDF can be configured to "autoregister" addresses going to SNADS. That is, when PMDF sees a "long" address going to SNADS, PMDF can automatically generate a unique short form address, substituting the generated short form in as the From: address on the message going to SNADS, and looking that short form up and substituting the true "long" address back in if a SNADS recipient replies using that short form address. See Section 3.7 for details.
• PMDF's addressing channel can be used as a way to let SNADS users send to any arbitrary address reachable through PMDF. SNADS users can send a message to, e.g., MAILMAN@PMDFnode, with the actual long form RFC 822 recipient address embedded in the text of the message and specially marked for PMDF's use, and PMDF will pull the real address out of the message text and resend the message to that specified address. See Section 27.1 for details on the format for embedding such addressing information in the text of the message.