The
pf.boot.conf file is used as initial configuration for the
pf(4) packet filter. This file is loaded before the network is configured by the
rc.d(8) script
network. Its purpose is to protect the machine from possible attacks between the network configuration and the loading of the final ruleset.
The syntax of this file is described in
pf.conf(5).
Note that at the stage the configuration is loaded, the network interface(s) do not have an IP address yet, so you
cannot use rules that derive addresses from an interface (for example: “pass out from any to fxp0”).