ipfw2 docs for dinamic rules

[Zoran Kolic]

   Dear FreeBSD!
   I would like to use custom rules
file with ipfw2. My computer goes
to the net via dial-up modem and
kernel ppp type. Since I don't have
experience with dinamic rules, but
want to, reading tutorials stranded
me somewhere in the middle. In
this moment I need recall of known
links to docs about topic. Provider
gives new address every time when
connected. One machine. Via ppp...
And most of all: dinamic rules.
   It was thread some months ago, but
cannot find it. If someone could remem-
ber those links, would be appreciate.
   Best regards

                          Zoran Kolic
                          kolicz at eunet.yu