Subject: Pup ID Server

  You set NS.TO.PUP.ALIST to be an alist of entries (nshostnumber . pupnumber).  For example, set it to be (((NSHOSTNUMBER 125000Q 0 4661QQ) . 131Q)) to register the machine whose processor id (\MY.NSHOSTNUMBER) is 125000.0.4661 (as 3 16-bit octal numbers)..  Then just run (\PUP.ID.SERVER window) as a process.  With window = NIL, it displays nothing.