pass in all
pass in from any to any

block in proto tcp from any to any flags FUPEW/FSRPAUEW
block in proto tcp from any to any flags SF/SFRA
block in proto tcp from any to any flags /SFRAW

pass in proto { udp, icmp, tcp } from any to any flags S/SA
pass in from any to any flags S/SA no state
pass in from any to any flags any no state
pass in from any to any flags any
pass in from any to any keep state
pass in from any to any