Description

   If you do not specify a To: line, the Mail utility supplies a
   To: line composed of user names on the To: address list. If you
   do not specify a CC: line, the Mail utility supplies a CC: line
   composed of user names on the CC: address list. In either of the
   above cases, commas separate the user names.

   To add a message's From: field, you must have the SYSPRV
   privilege, and the Mail DECnet object must have the SYSPRV
   privilege on OUTGOING CONNECT (users can set the DECnet object
   privileges at their discretion).