@akoei:
But why LAN computers some time use LAN interface to go out, sometime use OPT1 interface? On another words, if I issue arp -a on a LAN computers, some time the 192.168.5.1 point to LAN MAC address, sometime point to OPT1 MAC address.
Any idea?
It doesn't matter, the firewall answers and works fine with either/or. It's probably a quirk of some sort in the FreeBSD ARP code when combined with if_bridge.