From, an OpenBSD-based firewall
Revision as of 10:47, 27 March 2014 by Fredrik (talk | contribs) (Example)
Jump to: navigation, search


A bridge works like a transparent switch/hub between two or more interfaces and computers behind any of the bridged interfaces can communicate with each other exactly as if they were part of the same network. The bridge will learn which computers are behind what interface based on their MAC address and will only forward traffic to the necessary interface(s) which reduces traffic load in the network.

For bridging two interfaces in two geographically separate locations over a tunnel see the article on EtherIP.


Below is a complete example in plain-text for bridging two local (LAN) interfaces with each other and computers behind both interfaces sharing the same DHCP server, default gateway and firewall rules. This can of course be configured using the graphical web administration, as well. Pay particular attention to the fact that the vr2 interface does not have any IP address assigned to it and that the computers will instead use the IP assigned to vr1 as their default gateway.

firewall {
	pass quick on lan label LAN
	pass in log quick on mgmt proto tcp to (mgmt) port {$mgmt_ports} label management
	match out on wan inet nat-to (wan:0) label NAT
	pass out quick on wan label outbound
interface bridge0 {
	firewall {
	member vr1
	member vr2
interface vr0 {
	description "Internet"
	group "wan"
interface vr1 {
	description "LAN"
	group "lan"
	group "mgmt"
interface vr2 {
	description "LAN"
system {
	authentication {
		user "admin" {
			password "admin"
	dns {