Through a command fifo you can instruct diald to answer an incoming ppp
connection. I modified the backUPSd.c code which watches DCD on a modem line
and made it monitor RNG (ring) instead. When RNG went high, I spawned a
process. I could get the RNG monitor to spawn a pppd that worked, but I
could not get it to command diald to answer properly.
The funkiest part is the diald-spawned PPPD would negotiate the connection
with the remote end but never pass any IP packets (that I could tell). I
could see the LCP, PAP, and IPCP packets logged in /var/log/debug and on the
"console" of the portmaster. But any attempts to telnet either way would be
futile.
The routes look good. All the interfaces look proper. I'm mighty puzzled.
My next step will be to turn on packet tracing on the PM (which I've never
done before).