Linux Networking Cookbook

4.2. Bridging Wireless to Wired

Problem

How do you integrate your wired and wireless clients so that they share an Internet connection and LAN services all in one big happy subnet? You know that when you have multiple Ethernet interfaces on the same box they cannot all be on the same subnet, but must all have addresses from separate subnets. You want everyone all in a single subnet, and don't want a lot of administration headaches, so how will you do this?

Solution

Your routerboard needs at least three network interfaces: your Atheros interface, plus two Ethernet interfaces. ath0 is your wireless interface, eth0 is the LAN interface, and eth1 is your WAN interface.

What we will do is build an Ethernet bridge between ath0 and eth0. Copy this example /etc/network/interfaces, substituting your own LAN addresses and your own ESSID. Remember to run /sbin/rw first to make the Pyramid filesystem writable:

	pyramid:~# /sbin/rw
	pyramid:~# nano /etc/network/interfaces

	##/etc/network/interfaces
	## wireless bridge configuration
	auto lo
	iface lo inet loopback

	auto br0
	iface br0 inet static
	       address 192.168.1.50
	       network 192.168.1.0
	       netmask 255.255.255.0
	       broadcast 192.168.1.255
	       bridge_ports ath0  eth0
	        post-down wlanconfig ath0 destroy
	        pre-up wlanconfig ath0 create wlandev wifi0 wlanmode ap
	        pre-up iwconfig ath0 essid "alrac-net" channel 01 rate auto
	        pre-up ifconfig ath0 up
	        pre-up sleep 3

You can test this now by networking with some LAN hosts that have static IP addresses. First restart networking on the ...