Linux Step By Steps

PPP Script & Options processing order

Regardless of which direction ppp connects (eg dial out, or answering call), a sequence of script and option files are accessed to handle that event.

The useage of some of the files make sense only in the context of the direction. Regardless, *all* files are looked for, in strict order.

It is not an error for any / all of these files to be missing.

Rule 1) The command line is an override.

Any syntax expressed on the command line, eg options, override any subsequent, conflicting options.

Rule 2) Conflicting options are legal in the chain of option files processed. The last option encountered overrides all others (except the command line)

Rule 3) ALL files are processed if found.

/etc/ppp/options Both
$HOME/(dot)pprc Outgoing per user
/etc/ppp/options(dot)pppn Incoming per 'line'

n = the ppp line established for incoming call(s), starting at ppp0

/etc/ppp/auth_up called ONLY if the peer authenticates
/etc/ppp/ip_up called once the ICMP protocol has been established
/etc/ppp/ipx-up called ONLY if ipx superimposed.

Of these, only ip_up is garanteed to fire.