Possibly why it's disabled by default.and also enable the corresponding but in /etc/ppp/ip-down to stop the ping when you disconnect:
# Stop ping if you started it in /etc/ppp/ip-up.
#killall ping 2>/dev/null
And this runs as root? What a bad piece of scripting...
Volker
Unless I'm missing something, it probably doesn't matter too much if all pings get killed when you disconnect your dialup. They aren't much use after your connection is gone anyway (?). I realise though (now!) it doesn't seem too robust [1].
Cheers,
Tim
[1] use case: connected to internal network and doing something that uses ping, also browsing internet on dial-up, disconnect and break other thing.
