Extending wifi using bridge router with Technicolor TG582N

[#1]

Hi. I am new to this and completely non technical so please be patient! I have the plusnet technicolor router and during a recent rewire had ethernet run through the house & to the garage. I'd like to connect an old airport extreme to give wifi in the garage. I've tried connecting it directly to the technicolor and that works ok but if I try to plug the airport into the garage ethernet socket (obviously also ethernet cabled from the router to the equivalent socket at the other end!) it can't connect to the internet. From what I've read, that is because the technicolor doesn't allow connection to the internet without changes to the settings but I have no idea how to overcome this. Can anyone tell me, without jargon or any technical knowledge required, how I can achieve it?

[#2]

Quote from: caroline233

I've tried connecting it directly to the technicolor and that works ok

That's a good sign, but the rest of the statement seems a bit contradicting. If AirPort works okay while connected to Technicolor directly, it has to work in garage too.
A couple of checks:

• How do you know AirPort is working  8)? Is it configured to use the same Wireless Network Name as Technicolor (PLUSNET-xxxxxx)?
  


• Do you plug Technicolor into Ethernet WAN port on AirPort in both cases, locally and in garage?
  


• Are Ethernet WAN port lights blinking in a similar way in both cases?
  

Worst case scenario - your Ethernet cable between garage and Technicolor is wired incorrectly. It's not a rocket science, but a wiring person has to do it right at least once in a lifetime. You can easily test the cable by plugging it in Technicolor on one end and into some computer on the other. The computer will be able to access the Internet if the cable is okay and even when its Wi-Fi is turned off.
Once Ethernet cable is confirmed to be working, all the rest can be accomplished by running AirPort Utility.
Important thing is to select Router Mode: Off (Bridge Mode) on Network tab. If roaming between the house and the garage is not essential or not possible, AirPort can use any network name, not necessarily PLUSNET-xxxxxx. All non-roaming devices would have to be configured for two wireless networks in this scenario. Configuring AirPort with Technicolor's Wireless Network Name might be beneficial - one password less to enter on every wireless device. Wireless Security would have to be configured as WPA2 Personal on AirPort in this case, and Wireless Password would be Technicolor's Wi-Fi Password (Key).
You'll be up and running in five minutes or so.
Oops! Almost forgot: The Internet tab on AirPort Utility should read 'Connect Using: DHCP'. Happy garage surfing!

[#3]

I've done something similar with a SpeedTouch and a Technicolor, and it will be similar for the Airport probably.  You need to turn off the DHCP server running on the one in the garage.  You want all ip addresses being allocated by the primary router in your home.  There's probably a check box some where in the settings.  Cann't help any more - don't like Apple.
http://npr.me.uk/together.html is a good reference.