• So you have just finished deploying a nice mesh at a gated community. (http://en.wikipedia.org/wiki/Gated_community)
• The body corporate is very happy with their investment until one of the customers started the following conversation:

What about my wireless printer? and the kids games?

Mam, I'm sure there is a way to fix this up. We just need to investigate our options.

Very good.

• Back home you grab some of those super cheap Atheros based Access Points lying around; flash it with OpenWrt and do the following changes:

• We will run the radio in both Station mode and Access Point mode simultaneously.
• We will use it in Station mode to join the mesh network which has an open SSID.
• We will use it in Access Point mode for the house to connect to this private fire-walled network.
• So in essence we simply replace the WAN interface that is traditionally eth1 with the one virtual WiFi interface running in station mode and is connected to the mesh's open SSID.
• See the following files and the comments inside them to explain what we are doing:
• /etc/config/wireless

wireless

config wifi-device  radio0
        option type     mac80211
        option channel  11
        option hwmode   11g
        option path     'platform/ar933x_wmac'
        option htmode   HT20
        # REMOVE THIS LINE TO ENABLE WIFI:
        option disabled 0
#This is the private SSID for the user's home
config wifi-iface
        option device   radio0
        option network  lan
        option mode     ap
        option ssid     OpenWrt
        option 'encryption' 'psk2'
        option 'key'        'passphrase'
 
 
#This is the uplink station mode interface joined to the wan network (where we removed the eth1 interface)
config wifi-iface
        option device   radio0
        option mode     sta
        option ssid     "Cheetah guest"
        option encryption none
        option network  wan
 

• /etc/config/network

network

config interface 'loopback'
        option ifname 'lo'
        option proto 'static'
        option ipaddr '127.0.0.1'
        option netmask '255.0.0.0'
 
config globals 'globals'
        option ula_prefix 'fda0:c846:c916::/48'
 
config interface 'lan'
        option ifname 'eth0'
        option force_link '1'
        option type 'bridge'
        option proto 'static'
        option ipaddr '192.168.1.1'
        option netmask '255.255.255.0'
        option ip6assign '60'
 
#We replace the eth1 interface with the wlan0 interface
#This is the 'uplink' interface
config interface 'wan'
#       option ifname 'eth1'
        option proto 'dhcp'
 
config interface 'wan6'
        option ifname '@wan'
        option proto 'dhcpv6'

* /etc/config/dhcp

dhcp

config dnsmasq
        option domainneeded '1'
        option boguspriv '1'
        option filterwin2k '0'
        option localise_queries '1'
        option rebind_protection '1'
        option rebind_localhost '1'
        option local '/lan/'
        option domain 'lan'
        option expandhosts '1'
        option nonegcache '0'
        option authoritative '1'
        option readethers '1'
        option leasefile '/tmp/dhcp.leases'
        option resolvfile '/tmp/resolv.conf.auto'
 
config dhcp 'lan'
        option interface 'lan'
        option start '100'
        option limit '150'
        option leasetime '12h'
       #NB change from 'server' to 'disabled' for NAT through the CPE to work right
        option dhcpv6 'disabled'
        option ra 'server'
 
config dhcp 'wan'
        option interface 'wan'
        option ignore '1'
 
config odhcpd 'odhcpd'
        option maindhcp '0'
        option leasefile '/tmp/hosts/odhcpd'
        option leasetrigger '/usr/sbin/odhcpd-update'
 

• After these changes its time to reboot and test