Connect a wireless LAN to a WAN wirelessly

Using a router for this is somewhat overcomplicated. Just throw a wifi extender/repeater with an ethernet port into the mix. This will connect to and reshare the connection with no additional work, and you can connect an ethernet device to it. It will pass through DHCP.

Technically what you're looking for is a wireless bridge - but extenders are far more common.

Thanks to https://stackoverflow.com/questions/9841125/setting-up-a-repeater-with-dd-wrt for the sage advice. The recommendation was to use "client bridge" mode, first setting up client mode to test connection.

Note that at this moment I am currently connected to Router B through Router A which is connected wireless to the WAN.

Yes, it may be much easier to use a dedicated WiFi extender to do this, but if you have a couple wireless routers lying around or want to connect an existing wireless subnet to a WAN wirelessly, this may be just the thing.

So here it is, in only five simple(!) steps:

Step 1: Configure LAN-side router (Router A) as WAP

This router gets configured exactly asif it were a wired WAP. In fact, if you later find an ethernet WAN drop, you can plug in.

We assume this router has any old factory firmware.

1. Under WAN settings
   1. Set router in dynamic or DHCP mode
   2. Configure DNS to automatically be assigned by WAN router
2. Under wireless settings
   1. Wireless channel: Auto
   2. SSID: mysubnet
   3. Broadcast SSID: yes
   4. Security: WPA2 Personal (WPA2-PSK)
   5. Encryption: AES
   6. Wireless key (PSK):
   7. Wireless bridging: No
   8. Use as access point (WAP): No
3. Connect it to an ethernet WAN drop
4. Test WAN access by connecting to the mysubnet SSID

Step 2: If WAP-side router (Router B) is in an unknown or inaccessible state

This router we assume is flashed with DD-WRT firmware.

1. Do a 30-30-30 factory reset
2. Set your computer's static IP to 192.168.1.6 (255.255.255.0 mask, 192.168.1.1 gateway)
3. Connect to router at 19.168.1.1
4. Set the admin password

Step 3: Set WAP-side router (Router B) to client mode and connect to WAP

ref: https://www.dd-wrt.com/wiki/index.php/Client_Mode

Again, we assume this router is flashed with DD-WRT firmware.

1. Set your computer to static IP in same subnet as router (last 192.168.3.7)
2. Turn wireless off on your computer
3. Connect Router B to your computer in port 3
4. Login to WAP-side router running DD-WRT
5. Go to Wireless > Wireless Security
   1. Security Mode: (likely WPA2 Personal)
   2. WPA Algorithms: (likely AES)
   3. WPA Shared Key:
   4. SAVE (not APPLY)
6. Go to Wireless > Basic Settings
   1. Wireless Mode: Client
   2. Wireless Network Mode: (or try Mixed)
   3. Wireless Network Name (SSID):
   4. Network Configuration: Bridged
   5. SAVE
7. Go to Setup -> Basic Setup
   1. Connection Type: Automatic Configuration - DHCP
   2. Local IP Address: 192.168.3.1 (your local subnet)
   3. Gateway: 192.168.3.1 (same as this router)
   4. SAVE
8. Go to Security -> Firewall
   1. SPI Firewall: Disable
   2. APPLY
   3. Note that at this point Router B wll be re-IP'ed and you will lose connection to it
9. Reset your computer to DHCP (it should assign you an IP in the 192.168.3.0/24 subnet
10. Connect to the router at 192.168.3.1 and confirm wireless connection

Step 4: Set WAP-side router (Router B) to client bridge mode

ref: https://www.dd-wrt.com/wiki/index.php/Client_Bridge

1. Connect to Router B at its new address at 192.168.3.1
2. Go to Wireless > Basic Settings
   1. Wireless Mode: Client Bridge (from Client)
   2. SAVE
3. Go to Security > Firewall
   1. Under Block Wan Requests, uncheck everything (Block Anon WAN, Filter Multicast, and Filter IDENT are checked)
   2. Filter Multicast: checked
   3. SAVE
   4. APPLY
4. Go to Setup > Advanced Routing
   1. Operating Mode: Router
   2. APPLY
   3. Note that at this point you will lose connection to Router B

Step 5: Connect Router A and Router B together

1. Connect ethernet to port 3 of Router A
2. Connect other end of ethernet to port 3 of Router B
3. Turn wireless on your computer back on
4. Connect to SSID mysubnet (from Router A) with your chosen key
5. You should now be connected to Router A THROUGH Router B to the WAN
6. Test connection to internet