Saturday, November 10, 2012

DD-WRT client bridge mode

DD-WRT supports client bridge mode. This mode allows you to extend your network via a wireless router. Note, this does not extend the wireless coverage of the master router. The additional wireless router uses the same subset as the master router. Since the same subset is used for both routers, devices connected to one router can talk directly to devices on the other router. There are many guides online. Some of them do not explain caveats and some lists unnecessary steps. Here is my experience with configuring DD-WRT for client bridge mode.

This guide assumes that you already have a router running DD-WRT with wireless support enabled. We will call this the master router. We will configure an additional router also running DD-WRT for client bridge mode. We will call this the client router.

The master router

In the remaining steps, we will assume your master router has the Local IP address 192.168.1.1 and wireless is enabled. No additional changes need to be performed on the master router to support client bridge mode.

The client router
  • Access the network settings of your computer and give your computer the static IP 192.168.1.8 and connect your computer to the client router.
  • Administration->Factory Defaults->Reset router settings
    • Reset Factory Defaults
      • Let's reset the router to the default settings
  • Setup->Basic Setup
    • Router Name
      • Specify a different name from the master router.
    • Local IP Address
      • Specify a different Local IP Address from the master router. 192.168.1.2 is sufficient.
    • Subnet Mask
      • Specify 255.255.255.0
    • Gateway
      • Specify 192.168.1.1. Note, this is the IP of the master router.
    • Local DNS
      • Specify the same value as the Gateway: 192.168.1.1.
  • Wireless->Basic Settings
    • Wireless Mode
      • Select Client Bridge
    • Wireless Network Mode
      • Select the same setting as your master router
    • Wireless Network Name (SSID)
      • Specify the same name as your master router
  • Wireless->Wireless Security
    • Security Mode
      • Select the same setting as your master router
    • WPA Algorithms
      • Select the same setting as your master router
    • WPA Shared Key
      • Specify the same key as your master router
  • Access the network settings of your computer and set your network preferences to receive an IP from DHCP.
For me, the above steps were sufficient to have the client router functioning in client bridge mode.

Checking if the client has established a connection

To check if you the client router has connected to the main router, on the client router, go to Status->Wireless. Under Wireless Nodes->Access Point, you should see an entry with a MAC address. If not, the connection has not been established, and you will need to troubleshoot why the connection has not been made. See below.

Troubleshooting
  • Not all Wireless Network Modes work under client bridge mode. I was not successful at using BG-Mixed, for example. Try selecting other Wireless Network Modes.
  • Not all Security Modes work under client bridge mode. Try selecting other Security Modes.
  • If you are still having connection issues, try to test the connection by disabling both Wireless Network Mode and the Security Mode. This disables wireless security but this will confirm whether the problem is caused by the wireless security settings.
Additional Steps

It is not clear if these steps are necessary. I did not need to change them to have the client router function in client bridge mode.
  • Since NAT is handled only by the master router, the client should not need this support
    • Setup->Advanced Routing->Operating Mode->Operating Mode
      • Select Router
  • Since the Firewall is handled by the master router, the client should not need this support.
    • Security->Firewall->Firewall Protection->SPI Firewall
      • Select Disable
Optional Steps
  • Since the WAN port is no longer necessary, you can assign it to be a LAN port.
    • Setup->Basic Setup->Assign WAN Port to Switch
      • Select the checkbox.

4 comments:

Anonymous said...

Thanks for this post! I have managed to configure my DD-WRT router in client mode and it is connecting to my master router now and sharing the network with LAN clients wired to it (the DD-WRT).

With this setup is the DD-WRT also broadcasting its SSID? Can I turn that off so wireless clients only connect to the master router? (The DD-WRT SSID is set the same as the master router so I can't tell what is happening).

tsengf said...

danaus, have you tried disabling "Wireless SSID Broadcast" under Wireless->Basic Settings?

Unknown said...

Thanks a bunch have been trying to set up a router for use with a printer and could never get the routers to connect. Most of the other instructions had nothing to say about putting in the gateway and dns server as soon as I saw those on your instructions I thought it might be the answer and a few minutes later it was up and running. Kudos to you for being specific!
Thanks

Joe in MD said...

It is very non-intuitive that you can't use the DHCP of the AP to automatically configure the client just like any other (not DD-WRT) client.

That said, I tried a bunch of other "instructions" for creating a client without success but this worked. I did do the optional steps of selecting Router mode and turning off Firewall security.