POST is the network wide mailing facility and can be invoked by typing:

     .POST username @ host
or
     .R POST

POST will then respond by prompting for a username and a destination machine.

The username must be the userid, PPN, ID or whatever  is  appropriate  for  the
destination  machine.  The destination machine must be a machine title that FTP
understands.

If only a username is specified, SWITCH.INI will be searched for lines  of  the
form, e.g.

post/fred=fred smith@host1, jane=[100,100]@host2

and the string on the right of the equals sign will be substituted for a  match
of the string on the left of the equals sign.

For further details please consult 3A01C in the Installation Manual.