DOOR.ID

          Many maildoors now produce (and readers use) a file called
          Door.Id that was developed by Greg Hewgill.  It is intended
          to give the reader information on the capabilities of the
          door that produced the packet (and presumably will process
          the *.REP produced).  It is a straight text file with the
          following format.  Each line is in the format ControlWord
          space equals space value.


          DOOR = <doorname>
               This is the name of the door that created the QWK
               packet, eg.  <doorname> = Tomcat.

          VERSION = <doorversion>
               This is the version number of the door that created
               the packet,  eg. <doorversion> = 2.9.

          SYSTEM = <systemtype>
               This is the underlying BBS system type and version,
               eg. <systemtype> = Wildcat 2.55.

          CONTROLNAME = <controlname>
               This is the name to which the reader should send
               control messages, eg. <controlname> = TOMCAT.

          CONTROLTYPE = <controltype>
               This can be one of ADD, DROP, or REQUEST (or others).
               ADD and DROP are pretty obvious (they work as in
               Markmail), and REQUEST is for use with BBS systems
               that support file attachments.  Try out SLMR with
               CONTROLTYPE = REQUEST and use the Q function.

          RECEIPT
               This flag indicates that the door/BBS is capable of
               return receipts when a message is received.  If the
               first three letters of the subject are RRR, then the
               door should strip the RRR and set the 'return-receipt-
               requested' flag on the corresponding message.