
ipfw	= entry-action chain-entry | chain-action | check-action chain-entry .

entry-action = "addblocking" | "delblocking" | "addfowarding"
	| "delfowarding" | "addaccounting" | "delaccounting" .

check-action = "checkblocking" | "checkforwarding" .
chain-action = flush | list | zero .
chain-entry = permit protocol iface addrlist .

permit	= "deny" | "accept" .
proto	= "icmp" | "tcp" | "udp" | "all" .
iface	= "iface" ifname .
addrlist = "from" addr-mask [ports ] "to" addr-mask [ ports ] .
addr-mask = ipaddresss [ "/" maskbits | ":" mask-pattern ] .
ports	= portlist | portnum ":" portnum .
portlist = portnum [ "," portlist ] .

zero	= "zero" .
list	= "list" [ "fowarding" | "blocking" | "accounting" ] .
flush	= "flush" [ "firewall" | "accounting" ] .

