Create a private wireless network from an existing wireless network

Posted on 2014-08-04
Last Modified: 2014-12-24
I just moved into a multi-tenant office building. Comcast has set up a wireless network for the entire building. When you join this network from Windows, you are not prompted to enter a password. That is, this wireless network is not encrypted. However, before you can browse the web, you are prompted to log in from your web browser, using your Comcast login and password. Once I do this I can browse the web all day long with no problem. So this is an unsecure guest wifi hotspot that requires authentication using your browser.

Here's what I am trying to do:
In my office I have 2 more computers, a smart tv and a wireless printer. I haven't tried it yet but I suspect I will NOT be able to connect the SmartTV or the printer to this network. (Remember, when joining the wireless network you are never prompted to authenticate because it is not a secure network).

Is it possible to join this wireless network from ONE device in my office (such as a Linksys wireless router?), and then use that device to create a new (private, encrypted) network that I can use for my office?

This way I can:
(1) have peace of mind knowing the entire building can't see my devices and then
(2) join my smart tv and wireless printer to my newly created private network - not the one set up for the entire building.

So the basic question is - can I create a private wi-fi network from an existing wi-fi network?
Question by:ecarbone
    LVL 1

    Accepted Solution

    I highly doubt the above is possible from a security point of view. Any WiFi hotspot usually validate your MAC address and allow internet browsing. Even if you are able to purchase another Access Point and bridge the networks together somehow, the 2 devices would still need to authenticate with CommCasts access points to be able to use the WiFi.

    Expert Comment

    I do believe this is possible. I've done a similar thing before using a wifi access point in repeater mode. This in effect extends the existing wifi network but you can set your own DHCP and security settings.

    It all depends what device you can and whether it will support this configuration.   I think an Edimax device will do what you want.   You can contact them to confirm which device is suitable.


    Assisted Solution

    Daniel is right regarding authentication. It's possible that Comcast will not validate your other access point and thereby prevent you browsing. It is possible to connect one wifi subnet to another but it looks like they may be using proxy or IP web filtering authentication which could cause you a problem.

    LVL 10

    Author Comment

    I bought two Netgear devices but I haven't opened them yet: a Range Extender and a Wireless Router.

    This is my plan (and I have no idea if it will work) ... Set up the Range Extender to join the existing Comcast wireless network. Then, run an Ethernet cable from one of the 4 ports on the back of the Range Extender, to the WAN port on the Wireless Router. As far as the router is concerned, that's the Internet connection it should be using.

    Once the wireless router has Internet connectivity, turn on its wireless access point as a secure network that only the devices in my office will know the password to.

    Haven't tried any of this yet but I still see an issue: Remember in my original post I mentioned that at some point, a computer (using a web browser) must log in using a Comcast user name and password. As Daniel mentioned, the Comcast hot spot probably locks on to the MAC address of my laptop and therefore allows ONLY my laptop to connect to the Internet. So ... I wonder if there is a way to (temporarily) change the MAC address on my Windows 8 laptop (to be the same as the MAC address on the range extender), then open my web browser, log into Comcast, then change the MAC address back and then turn on the Range Extender. Even if that worked I wonder how long the lease is before I am required to log in again.
    LVL 44

    Assisted Solution

    by:Craig Beck
    You can only do this securely if you can get Comcast to create a separate SSID and VLAN for your office.
    LVL 10

    Author Comment

    As most of you indicated, I was not able to get this to work. It's a shame that in a multi-tenant building, Comcast still charges full price for every single office. These are one-room offices for rent so on one floor there are probably 50 businesses. Oh well. Thanks everyone for your help.

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