We are looking to provide public Wi-Fi in an area that currently isn’t covered by any Wi-Fi network.

However, nearby there is another Wi-Fi network of ours consisting of a DHCP router—with incoming Internet connection—and three wireless extenders.

For the new network we will need a new SSID set up for the public but we want to use the same internet connection from the existing network. Before we buy any new routers I wanted to check that it would be ok to just plug any wireless router into one of the three extenders, set its SSID to something different and it would still receive Internet connectivity just fine?

Then we would plug another extender into that new router to expand the coverage of the new network.

The new SSID would only need to be available through the new router (and new extender), so won’t need multiple SSIDs from any single router.

To me that sounds like it should work, but it is using a bit of daisy chaining so wanted to check.

Here’s a diagram of what I currently have (Private network - left) and what I want to add on (Public network - right). Lines represent ethernet cables.

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At the moment all the extenders are just old routers that where I have simply turned off the DHCP server and set them to the same network SSID as the main router.

Whatever I buy could be a router or a wireless access point, as long as one of them has the ability to be a DHCP server.

  • I'm having a hard time mapping out in my head exactly what you are trying to achieve. Any chance you can draw up a diagram? Also, by router, do you mean just that, or do you mean an Access Point?
    – Jarmund
    Apr 15, 2015 at 16:48
  • It is a bit confusing, i've added a link to a basic diagram. Hope that makes it easier to understand. I'm not entirely clear in my mind what the difference is between a router and an access point.
    – chris_huh
    Apr 15, 2015 at 17:10
  • Setups like this are very hardware dependent. The devices themselves have to specifically support it. Do you have the make/model numbers for the equipment in question?
    – Wes Sayeed
    Apr 15, 2015 at 18:06
  • The current ones are all BT Homehubs. One Homehub 5 as the DHCP server, and three Homehub 3's. I guess all that needs to happen is for the internet connection to be shared from one extender, via ethernet, to the new DHCP server. I could easily test it if i was there.
    – chris_huh
    Apr 15, 2015 at 19:08

2 Answers 2


You want to isolate the open Wi-Fi from your LAN. Your diagram leaves your local network wide-open.

One way to do this cheaply is by building your own firewall: set up a computer with 3 LAN cards: 2 Ethernet, and one Wi-Fi.

You would use firewall software like (free) Smoothwall, and assign the wifi card as a PURPLE interface. The other two ethernet cards would be RED and GREEN.

  • RED connects to your broadband (the Internet).

  • GREEN connects to your switch (the LAN).

  • PURPLE is isolated from GREEN: They cannot talk unless specially configured.

You can use an existing Wi-Fi router for your GREEEN local network by connecting one of the non-WAN ports to the switch. Turn on authentication and turn off DHCP services on this router.

Firewall software also provides for an ORANGE interface, but my understanding is that this allows for a DMZ and is not by default completely isolated from the private LAN


It might be worth a phone call to your provider to find out if you're allowed to have more than one WAN IP. If you are, and as long as you don't mind the two networks being completely separate, then you just need a dumb switch inside your modem. Connect two routers inside the switch, both configured for WAN DHCP, and they should both pull unique IPs from the provider. The two routers can be configured any way you want, including DHCP on the LAN side, WiFi, etc. This is the setup I'm using now and it's great. Unfortunately, not all providers allow more than one IP. In my case, I had to call Shaw and ask them to enable the second IP, but it didn't cost anything extra. There are ways of doing this without the extra switch, but they tend to be more complicated.

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