PMDF Obsolete Features

This section is only of interest to sites not running a BITNET "mailer" (i.e., BITNET gateway or trusted mailer). Note that the January 1, 1992 CREN regulations require BITNET sites wanting to send mail to the Internet to run a mailer. Process Software recommends that all sites register themselves as a mailer and configure their PMDF to operate as a BITNET gateway.

NJE can only deal with mailbox names containing 8 or fewer characters. OpenVMS, on the other hand, allows usernames with up to 12 characters in them (and supports mail forwarding aliases up to 31 characters long).

Jnet deals with this problem by delivering mail to the first user with a name that matches in the first 8 characters --- even if there is more than one username which matches in the first 8 characters. Note that this scheme, while effective in some cases, is not a general solution to the problem. In particular, it does not handle mailboxes that do not correspond to an actual user on the system (i.e., an alias) properly.

PMDF's local mail delivery facility also does do this type of matching, but only as a last resort. When PMDF encounters a potentially truncated mailbox name it scans appropriate lines in the message header (first the X-Envelope-to:, in the hopes that the message originated with another PMDF mailer, and then the Resent-to:, Resent-cc:, To:, and Cc: lines) looking for an address that could have been the one that was truncated. The comparison is done very cautiously in order to limit the possibility of a spurious match. If a matching address is found it is used in lieu of the truncated address. If this process fails the Jnet strategy is used instead with one notable and important exception: if the truncated username matches the first 8 characters of more than one username in the SYSUAF then the mail is bounced as undeliverable rather than run the risk of delivering to the wrong user.

This mechanism is still not entirely satisfactory. There is no guarantee that the address of the addressee is actually present in the message header! So PMDF offers an additional technique for dealing with long usernames: Set up a local mailer (BITNET gateway channel) and use it for incoming mail traffic. Gateways do not inherit the 8 character name length restrictions of NJE. This is the preferred solution in all cases.

One final possibility is to simply require all usernames and aliases to be 8 characters or less in length. This is usually not practical unless it can be done at the time the system is initially configured. In this case it is recommended for systems that are going to make extensive use of Jnet.