PMDF-X400 is a gateway between PMDF and Message Transfer Agents, or MTAs, which conform to the 1992, 1988, or 1984 specifications of the X.400 recommendations for Message Handling Systems. The PMDF-X400 gateway provides address and message conversion between the X.400 P1/P2/P22 representation and the RFC 822 and MIME (RFCs 2045--2049, Multi-purpose Internet Mail Extensions) message representation used by PMDF. MIME and X.400 features such as multiple body parts and non-text body parts (e.g., file attachments) are supported.

PMDF with PMDF-X400 can provide X.400 gateway services to any remote mail system that has connectivity to PMDF. For example, DECnet or TCP/IP hosts that can interchange messages with PMDF can make full use of a PMDF-X400 gateway in order to interchange messages with X.400 mail users. Viewed from the X.400 side, PMDF and PMDF-X400 provide an X.400 MTA conformant with the 1992 recommendations.

PMDF-X400 can be configured to communicate with one or more remote X.400 MTAs. If multiple remote MTAs are connected, PMDF-X400 can be configured to route messages between them.

PMDF-X400 uses a rule-based algorithmic process to convert between RFC 822 and X.400 addresses. Because this process is not implemented as a simple table-lookup, as are some other X.400 gateway implementations, PMDF-X400 does not require that users of the gateway be registered in order to use the gateway. If restricted access to the gateway needs to be enforced, PMDF itself provides generalized access restrictions which can be applied to PMDF-X400 channels.

Default rules for address conversion are provided which conform to RFC 2156; (RFC 2156 updates RFC 1327). Other types of conversion can be implemented, if desired, by changing or adding to the rules in the address conversion databases.

This chapter describes the structure and configuration of PMDF-X400. Before configuring PMDF-X400, PMDF must first be installed; the PMDF installation will also install PMDF-X400. See the appropriate edition of the PMDF Installation Guide for instructions on installing PMDF and PMDF-X400.