ipwf firewall stock rule types ?

[Ronald F. Guilmette]

I'm setting up a new server, from scratch, and I find that it's always
best to review relevant sections of the Handbook when doing so, especially
if one hasn't done this fopr a long time, which I haven't.

This page has me a bit puzzled:

  https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/firewalls-ipfw.html

This page says that the stock ipfw firewall rulesets are as follows:

    open: passes all traffic.
    client: protects only this machine.
    simple: protects the whole network.
    closed: entirely disables IP traffic except for the loopback interface.
    workstation: protects only this machine using stateful rules.
    UNKNOWN: disables the loading of firewall rules.
    ...

I'd just like to know what the differences are between "client" and "simple".

Can anyone explain that to me, briefly?