I have ppp-2.3.10-3 installed under Redhat 6.1 and have
ppp configured to work in demand-dial mode.  This is
working as advertised.  Recently, I added some code to
/etc/ppp/ip-up.local, but pppd does not always execute
that code.

Here's what I've tracked down so far:

1) The very first time that pppd brings the link up,
   it executes if-up (which in turn executed if-up.local).
   It is able to successfully reap the death of this child
   process.  So far, so good.
2) When pppd drops the link due to inactivity, it runs
   if-down.   However, it does not properly reap the
   death of this child process.  As such, it does not
   have a chance to call ipcp_script_done to reset some
   variables it uses.  In particular, ipcp_script_pid remains
   set to the pid of the ip-down script.
3) The next time pppd brings the link up, it checks to see if it
   should run the ip-up script.  It does this by seeing if
   the ipcp_script_pid variable is 0.  If so, then it runs
   the script.  But since the variable was never reset
   properly, pppd will never run the ip-up or ip-down scripts
   after the very first time.

If you need additional information, please email me and I'll
provide it.

Jack Rann