Sharing WiFi with multiple devices

I haven’t needed to share a WiFi connection for quite a while but the need came up recently and I decided to revisit my popular blog post “Sharing a wireless hotel Internet connection” from April 2010…Wow. How did anyone follow this convoluted post??? I’m so sorry. Obviously it’s time to write a more straight forward one.

Things have really shrunk since I first tried this! I got the *tiny* TP-Link 703N on eBay with DD-WRT pre-installed for just $27! This thing is crazy small! Note the model number here. This one is not available in the US and mine came from China. Do not confuse it with the identically looking 702N which doesn’t support DD-WRT.

Ok, now for the tutorial on how to share a WiFi connection. The version of DD-WRT is v24-sp2.

Setting up DD-WRT to Share a WiFi Connection

1. Connect your device/PC to the TP-Link using an Ethernet cable or via WiFi (the default network SSID is dd-wrt).
2. Open a browser and navigate to 192.168.1.1. The DD-WRT control panel will open.
3. Log in. The default DD-WRT password is admin (the default username is root).
4. Go to Setup > Basic Setup tab. Make sure Connection Type is set to Automatic Configuration – DHCP and change the default Router IP Address to a subnet you don’t use. Here we are changing to 192.168.9.1
   
5. Click the Apply Settings button at the bottom and the router will reboot. (This will actually update the router settings rather than just storing any changes, which is what the Save button does.)
6. If you are connected via WiFi, check your WiFi connection. You may have to reconnect to the dd-wrt network again because of the reboot.
7. Browse to the routers new IP address (e.g. 192.168.9.1) and log in.
8. Go to the Security > Firewall tab. Disable the SPI firewall and uncheck anything else you can. Click the Save button at the bottom of the page.
   
9. Go to the the Wireless > Basic Settings tab. Change the Wireless Mode to Client. (NOTE: For some routers, you may need to select Repeater instead of Client.) For the Wireless Network Name (SSID), enter the WiFi network name you are trying to share (e.g., the hotel WiFi network). Click the Save button.
   
10. Go to Status > Wireless and click Site Survey at the bottom. Look for the desired network in the list that appears and click the Join button on the right. Note that hovering over the entry in the Open column will tell you what type of password security is being used. Make a note of it.
11. Go back to the the Wireless > Basic Settings tab. Click the Add… button. This will set up a “virtual” access point, that is, the one that your devices (iPhone, iPad, laptop, etc.) will connect to. You shouldn’t have to change any of the settings here. The name defaults to ddwrt_vap which is fine, but change it if you want to use a different name.
    
12. Go to the Wireless Security tab.
13. If the access point you are connecting to does not have a login, you can leave the Physical Interface Security Mode to Disabled. If it does require a login, use the security mode type info you got previously from the Site Survey. If it does require a login, it can require some trial and error because you need to know the type. If the passphrase is words, it is likely WPA or WPA2. If it looks like random letters A-F and numbers 0-9, it may be WEP.If WPA/WPA2, you must also set the Algorithm. Try TKIP +AES first (If you have issues connecting later, then try AES, then TKIP). Next, enter the passphrase into the Shared Key field.Click Save when you are done.
14. If you want to secure your virtual access point, set the Virtual Interface security settings as desired.
    
15. Ok, the set up is done. Click Apply Settings and your router will reboot.
16. It may take a few minutes but you should eventually see WiFi network called ddwrt_vap. Connect to it.

Note that every time you want to connect to a new WiFi network, you’ll need to update the Physical Interface SSID and security settings. Nothing you can do about that.

Troubleshooting

If it connects but you don’t get Internet access, try changing the Physical Interface security settings. If you need to start all over, just reset your DD-WRT router. On the TP-Link 703N, this is done by holding down the reset pin for about 5 seconds until the blue light glows.

Conclusion

Obviously, sharing a WiFi connect is great when you have to pay for it. However, there are even some benefits if its a free. Only one device needs to agree to terms. You also don’t need to change the WiFi logins on all of your devices, assuming they remember previous connections. You can place the router is a location that gets the best WiFi reception which isn’t always a convenient location in the room.

UPDATES
2014-01-27: I inadvertently had the wrong Wireless mode. I should be just Client. Text and photos updated. The Client Bridge (Routed) mode puts everything on the same subnet, which is not what you want. Apologies.