Friday, March 12, 2010

Wireless bridge from DD-WRT on WRT54GL

Installing DD-WRT on a Linksys WRT54GL router and creating a wireless bridge

The Linksys WRT54GL router is not a bad router. It comes with a flexible Linux OS and is stable. I however need a feature not supported in the Linksys firmware, a wireless bridge. This functionality normally requires one to purchase much more expensive hardware. I purchased these Linksys routers for $65 each from Amazon.com. I selected these for several reasons. They are solid devices with a great hardware track record and they have detachable antennae which I can replace with directional antenna, which are already on location in Honduras where these are going once I configure them.

Downloaded both the mini firmware and the standard generic firmware from the DD-WRT site. http://www.dd-wrt.com/site/support/router-database These were downloadable after selecting the router model number.

login to the router at http://192.168.1.1 using the default blank user and password = “admin”

Since I am not using a production model, I skip the normal step of returing to factory defalut as it already is. I then flash the router with the micro build (dd-wrt.v24_micro_generic.bin) as an intermediate step. This is because the Linksys firmware will produce an error if the new image is over 3MB. Proceed to reset the hardware by holding down the reset button for 30 sec, unpluging for 30 sec while reset still down, then keeping the reset button down for 30 sec more. It takes another 30 seconds for the lights to quit blinking at which point I plug into my laptop again. I cycle the power off and on again as instructed then log into the router with defaults: 192.168.1.1 user: root password: admin

Now I upgrade the firmware to the standard generic (dd-wrt.v24_std_generic.bin). Reset the hardware once more as above.


Primary router: setup as Wireless Access Point


The principal router in the pair will be setup as a wireless access point as it is not desired to route or NAT computers behind the router, but rather to connect them to the principal DHCP server, etc. This is the router that will send the wireless signal out to be picked up by the remote router.

Starting with factory defaults:

Setup/Advanced routing

*changed operating mode to Router

Wireless/Basic Setup

*change SSID to “myNewSSID”

*changed wireless channel to that desired (1 in my case)

*disable broadcasting (as I am wanting this to be used for linking only)

*kept sensativity range the same but unsure if I will need to adjust this later

Wireless/Wireless Security

*leave insecure for now, but will add security after confirmed working

Services/Services

*disable DNSMasq

*disable ttraff Daemon

Security/Firewall

*uncheck all boxes excpet Filter Multicast

*disable SPI firewall

Administration/Management

*disable Info Site Password Protection

*disable routing

Setup/Basic Setup

*disable WAN connection type

*change router name as desired

*change local IP address to a unique IP address out of the DHCP pool

*set Subnet Mask as appropriate

*set Gateway and Local DNS to the address of the primary server

*select assign WAN port to switch, which allows you to use the WAN port as another switched interface, otherwise it is disabled. This dummy proofs the box so someone cannot plug the cable into the WAN port and wonder why the access point does not work

*disable DHCP server and uncheck the DNSMasq options


Settings are saved on each page. When they are all saved, select apply settings and cycle power.

Tested by connecting network cable to back of router then testing wireless connectivity.

Second Router:

Install the DD-WRT system as before. Make the following modifications, saving after each page, then applying changes only when all changes are made.

Wireless/Basic Setings

*change wireless mode to Client Bridge

*change the network mode and SSID to match the primary router

*disable SSID broadcast as I do not intend anyone to pickup the signal

Wireless/Wireless Security

*leave insecure for now, but will add security after setup is working

Setup/Basic Setup

*disable WAN connection type

*change router name as desired

*change local IP address to a unique IP address out of the DHCP pool

*set Subnet Mask as appropriate

*set Gateway and Local DNS to the address of the primary server

*select assign WAN port to switch, which allows you to use the WAN port as another switched interface, otherwise it is disabled. This dummy proofs the box so someone cannot plug the cable into the WAN port and wonder why the access point does not work

Setup/Advanced Routing

*set Operating Mode to Router

Security/Firewall

*uncheck all boxes excpet Filter Multicast

*disable SPI firewall

Administration/Management

*select apply setting

*select reboot router


Tested the connection by hooking up my laptop to a wired port on the client bridge and connecting through the router connection. Everything works perfectly! Next added security to both routers as follows:


Wireless/Wireless Security

*change security mode to WPA Personal

*select TKIP algorithm and add the same key to both routers


Save and reset each router, starting with the one most distant from your computer.

Use the signal quality indicator on the Status/Wireless page to adjust antenna for maximum signal quality. On the Administration/Management page change the language to Spanish since these routers will be shipped to Honduras. A last minute change was to set the style to chromo on the Administration/Administration page since the Status pages were not showing up with the default "elegant" style.