PMDF System Manager's Guide
PMDF-REF-6.0

To provide access to remote DECnet MAIL and PSIMail via the local channel, versions of PMDF prior to version 3.2 used rewrite rules of the form

red.okstate.edu      $U$%RED@yellow.okstate.edu 
green.okstate.edu    PSI$%101202::$U@yellow.okstate.edu 
blue.okstate.edu     $U$%BLUE@yellow.okstate.edu 
slate.okstate.edu    $U$%GRAY@yellow.okstate.edu 

red.okstate.edu      RED::$U@yellow.okstate.edu 
green.okstate.edu    PSI$%101202::$U@yellow.okstate.edu 
blue.okstate.edu     BLUE::$U@yellow.okstate.edu 
slate.okstate.edu    GRAY::$U@yellow.okstate.edu 

The problem with this scheme is that while these rewrite rules provide full access to the remote systems, they also rewrite addresses in message headers, resulting in undesirable header address formats.

Enhanced rewriting facilities introduced with PMDF V3.2 make it possible to avoid this problem and still provide the necessary access to remote systems. This is accomplished as follows:

• Use the rewriting rules only to canonicalize addresses, that is, the rewrite rules convert all possible incoming addresses into the proper domain format addresses that should appear in the message headers.
• Use the DECnet MAIL-11 channel (d channel) to provide access to remote DECnet systems. Use special MAIL channels to provide access to PSIMail.
• Use appropriate channels in conjunction with channel-level translation operations (in the channel block) to map domain address back into DECnet MAIL or PSIMail addresses. If possible mark the channel with the 733 keyword and use domain names whose leftmost section (the part before the first period) corresponds to the DECnet MAIL or PSIMail system name in order to lessen the number of channel-level translation operations that are needed.

  For example, the rewrite rules shown above could be implemented in PMDF with the following rewrite rules and channel blocks:

  red.okstate.edu      $U@RED.OKSTATE.EDU 
  red                  $U@RED.OKSTATE.EDU 
  green.okstate.edu    $U@GREEN.OKSTATE.EDU 
  green                $U@GREEN.OKSTATE.EDU 
  blue.okstate.edu     $U@BLUE.OKSTATE.EDU 
  blue                 $U@BLUE.OKSTATE.EDU 
  slate.okstate.edu    $U@SLATE.OKSTATE.EDU 
  slate                $U@SLATE.OKSTATE.EDU 
  gray                 $U@SLATE.OKSTATE.EDU 
   
  ... 
   
  d 
  DECNET-MAIL 
  RED.OKSTATE.EDU      RED 
  BLUE.OKSTATE.EDU     BLUE 
  SLATE.OKSTATE.EDU    GRAY 
   
  mail_psi 
  PSI-MAIL 
  GREEN.OKSTATE.EDU    101202 
  

  Or, using the 733 keyword to simplify things somewhat:

  red.okstate.edu      $U%RED.OKSTATE.EDU@DECNET-MAIL 
  red                  $U%RED.OKSTATE.EDU@DECNET-MAIL 
  green.okstate.edu    $U@GREEN.OKSTATE.EDU 
  green                $U@GREEN.OKSTATE.EDU 
  blue.okstate.edu     $U%BLUE.OKSTATE.EDU@DECNET-MAIL 
  blue                 $U%BLUE.OKSTATE.EDU@DECNET-MAIL 
  slate.okstate.edu    $U@SLATE.OKSTATE.EDU 
  slate                $U@SLATE.OKSTATE.EDU 
  gray                 $U@SLATE.OKSTATE.EDU 
   
  ... 
   
  d 733 
  DECNET-MAIL 
  SLATE.OKSTATE.EDU     GRAY 
   
  mail_psi 
  PSI-MAIL 
  GREEN.OKSTATE.EDU    101202 
  

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