You may not need to edit the client's /etc/ppp/options file at all. You will if the "auth" option is present, or some of the other priveledged options. Try it, and if it fails, a black /etc/ppp/options will work. just keep adding the options from the old file to figure out which one broke it (if it's not obvious) and see if you can get around that. Maybe you don't need them at all. You probably don't if you don't use pppd for anything else.