The $HOME/.ppprc file is intended for users who are configuring preferred PPP options. As administrator, you can also configure $HOME/.ppprc for users.
The options in $HOME/.ppprc are privileged only when the user who is invoking the file is privileged.
When a caller uses the pppd command to initiate a call, the .ppprc file is the second file that is checked by the pppd daemon.
See Setting Up Users of the Dial-in Server for instructions about setting up $HOME/.ppprc on the dial-in server.