Why use pty-redir when ppd already has a ``pty'' command line switch within it? In other words, a command along the lines of this will work and require fewer steps than the original script:
/usr/sbin/pppd pty '/usr/bin/ssh -t firstname.lastname@example.org' local noauth proxyarp
In addtion, note the ``-t'' option used with ssh so that it knows to force a pseudo-tty allocation.
Finally, note that the ``defaultroute'' option is available and could remove even a few more steps from the original script. The nice things about these options is that pppd will shoulder the responsibility for cleanly shutting down the ssh and deleting the route whenever pppd needs to quit.