I would suggest, since this is likely to be encounterd by users, rather
   than just by programmers, that pppd be changed so that it will catch
   invalid speeds in options, or the command line, and generate a helpful
   error message.

   Sending users to the tcsetattr man page to try to figure out why their pppd
   options are not working is cruel.


actually, it should probably generate a more helpful error message, but
having pppd check what is valid is wrong:  what if i change the zs driver
to fudge?  or even use a serial chip that supports `any' baud rate?