Dumb AP
This document describes how to create an Access Point that's really just that, no routing, no DHCP, no nothing. This AP allows users to connect to the AP over wireless or ethernet. I needed this setup because access control is already in place here through 'static DHCP' and I didn't want another access control mechanism.
From a user point of view it works like this:
- Connect to the AP (in case of wireless WPA2 encrypted, hence a password is needed)
- If the MAC of the users network interface matches a MAC in the list, it gets the appropriate IP and the user has network access (possibly not the best way to control network access…)
'Static DHCP' is not covered here, all we do is creating an AP that provides WPA2 encrypted wireless access and doesn't interfere.
Configuration
The changes below assume an OpenWrt default configuration, the relevant files are:
Step 1: Modify the Network
Edit /etc/config/network and change the interface section:
For switch-less devices, e.g. Alix Board
On switchless devices, simply bridge all ethernet interfaces together, remove the existing WAN interface - if any.
config interface lan
option type 'bridge'
option ifname 'eth0 eth1' # Bridges lan and wan
option proto 'dhcp' # Change as appropriate |
For devices with switch and dedicated WAN, e.g. WNDR3700
On devices with a separate WAN interface, bridge the LAN VLAN together with the WAN interface, remove the existing WAN interface - if any.
config interface lan
option type 'bridge'
option ifname 'eth0.1 eth1' # Bridges vlan 1 and wan
option proto 'dhcp' # Change as appropriat |
For devices with switch only, e.g. WRT54GL
On devices where WAN and LAN are separated by switch config, reconfigure the LAN VLAN to cover all ports, remove the existing WAN interface and its related VLAN - if any.
config switch_vlan eth0_0
option vlan '0'
option ports '0 1 2 3 4 5t' # Might vary depending on the device
config interface lan
option type 'bridge'
option ifname 'eth0.0' # Might vary depending on the device
option proto 'dhcp' # Change as appropriate |
Step 2: Change the existing wireless network
Edit /etc/config/wireless, and don't worry about most of it, things that might need changes are commented.
config 'wifi-device' 'radio0'
option type 'mac80211'
option channel '11'
option macaddr '12:e4:4a:b3:83:1a'
option htmode 'HT20'
list ht_capab 'SHORT-GI-20'
list ht_capab 'SHORT-GI-40'
list ht_capab 'TX-STBC'
list ht_capab 'RX-STBC1'
list ht_capab 'DSSS_CCK-40'
config 'wifi-iface'
option device 'radio0'
option network 'lan' # Set to the name of the bridged interface
option mode 'ap'
option ssid 'ap_myaccesspoint'
option encryption 'psk2' # Change as appropriate
option key 'ap_password' |
Step 3: Disable DHCP Server
If you still need dnsmasq running for something else (e.g. TFTP server) you can do:
uci set dhcp.lan.ignore=1 uci commit dhcp /etc/init.d/dnsmasq restart
Step 4: Disable Firewall
/etc/init.d/firewall disable /etc/init.d/firewall stop
Apply changes
Reloading the network config should be enough, it should automatically restart if necessary.
/etc/init.d/network reload
IPv6
If you would like your AP to receive IPv6 as a host only and not for routing you have to tell dhcp6c not to request prefix deligation. If you do not do this the AP will reject basic IPv6 addresses.
config interface 'wan6' option proto 'dhcpv6' option ifname '@wan' option reqprefix no
Multicast Forwarding
Multicast forwarding is necessary for DLNA and UPnP clients to work properly. For example PS3, xbox, TVs and stereos use DLNA to detect, communicate with and stream audio/video over the network. Since multicasting is turned off (multicast snooping is turned on) by default in newer OpenWrt releases, it must be activated. This would forward any multicast packets to all ports allowing your TV to find your DLNA capable NAS with movies. In large networks, this could cause some overhead which may not be desirable.
Add this into /etc/rc.local
echo "0" > /sys/devices/virtual/net/br-lan/bridge/multicast_snoopingReplace br-lan with your actual bridge interface, sometimes also called br0.
This will forward all multicast packets to all ports on your bridge, making igmpproxy or udpxy proxies unnecessary.
doc/recipes/dumbap.txt · Last modified: 2013/04/20 06:49 by gatak