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Background

A short sketch of my situation before I formulate my question: I am on a large home network, which is privately administered by a couple of admins. The network consists of a lan and a wireless lan, and controls access centrally by filtering mac addresses (and denying/allowing based on whether they allow that specific mac address).

I have two computers that I have registered and use (and pay for monthly) on this network, one wireless connection (laptop) and one cable connection (desktop). So I have two mac addresses that are allowed on the network, and are allowed access to the internet through the network.

The problem

The problem is that the wireless access is very unreliable, and is unusable for me. The admins of the network don't have a lot of time and are a little lax, so they won't help me with my wireless access problems, even after repeated complaints. They basically told me to fix it myself. Which leaves me with a connection that I'm paying for, but unable to use. I don't have control over the main routers, so I am kind of cut off from the internet on my laptop because of this, which is very frustrating.

My (partial) solution

Fortunately, the mac address filtering is rather simple. The wireless mac address that I've registered does not allow me to access the cable lan part of the network. So I have only one valid mac address (from the desktop) that is allowed on the cable lan part of the network.

What I have done is patch a small router (E-Tech RTVP03) to the main network, change it's mac address to the allowed (desktop) mac address, and patch my computer and laptop to the router. This sort of works (internet access works), but there are some problems that I wasn't able to fix:

  • The mac address of my router and desktop computer network card is now the same, which causes a lot of conflicts. I have tried to change the mac address of my network card, but that didn't help (or maybe the changing of the mac address didn't work, I'm not sure).
  • Because the router is between my computers and the rest of the network, I can no longer discover any other computers on the network. Which is a shame, because we share a lot of files on it. Could I change the settings so this becomes a possibility again?

My question

So basically, what I want the router to do, is be as transparent as possible, and only change the mac address information that is passed to the main network (to bypass the mac filtering), and to allow me to share one connection over two computers.

I still want to be able to share files with the main network, and all I want to do is to be able to connect both my computers to the cable network, and have full internet (and network) access with them (because after all, I'm paying for it).

Can anyone come up with a good solution for this?

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6  
How is this not malicious? You are trying to bypass a policy. –  Lucas Kauffman May 9 '12 at 8:55
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@LucasKauffman Because I am paying for access, but not getting it. They won't help me with it, so I am only trying to get access to a network that I am paying for anyway.. –  Samuel May 9 '12 at 8:58
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You're intentions do not matter. Deliberately bypassing a policy is still malicious. No matter what your goal is. –  Lucas Kauffman May 9 '12 at 9:03
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If I were in your shoes I would get another ISP and simply not pay them. –  Lucas Kauffman May 9 '12 at 9:25
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@LucasKauffman Please stop your crusade. This is not Server Fault. Bypassing a policy is not inherently malicious or forbidden here. On the other hand, I don't think the question is on-topic here: this is a functional issue, not a security issue. Samuel, what operating system are you running on your computers? What operating system does this router run? If it's Linux, this question can be migrated to Unix & Linux. Otherwise, I think Super User would accept it. –  Gilles May 9 '12 at 17:22
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3 Answers

up vote 3 down vote accepted

All though I think this is not the correct way to solve your problem:

What I would do is get another networking card for your desktop and a router that is also wifi capable.

Get a box that's DD-wrt/open-wrt capable and change the MAC address to the one of your desktop or just get them to insert the MAC address of your router. After that you can just use your own router as WIFI AP and physical internet AP. No you won't be able to discover other devices.

I'm not sure how the auto discovery function works, but I think it will scan devices in the same subnet. Since you are behind another router this will not be case. What you can try is to directly connect to the ip of the fileserver.

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This is might be a bit of a hacky solution, but couldn't you use your desktop machine as a gateway, sharing access over WiFi using NAT? You could accomplish this using iptables in linux.

This would mean you get access to the "shared stuff" on your "ISPs" local network on your desktop (but not behind the NAT), while still being able to connect to the network using wifi (due to the NAT you've set up on the desktop machine).

It's hacky, but I think it would work. You would have to keep your desktop running when accessing the wifi however..

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So the NAT would require the laptop to connect to the desktop via wifi? Because I don't have wifi on my desktop, and that would mean I would have to buy a wifi router right? Could this maybe also be done with the existing cable router I already have? –  Samuel May 9 '12 at 11:05
    
By the way, the desktop having to be on is not a problem, as I will only need the extra connection when the desktop is already occupied. –  Samuel May 9 '12 at 11:09
    
This would in essence "turn your desktop in to a router". So the reason you can browse the shared stuff on the network is because that browsing is done "on the router". The router will drop the traffic relating to the file sharing normally, and it will not be allowed to pass through to the network behind it. EDIT: You would need to buy a new network card, with wireless capabilities. –  Jonatan May 9 '12 at 11:10
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This is quite a while after, but hopefully other people might read this and be helped.But anyways, after my (mis)adventures with WiFi in a college dorm room, I found often times routers have an "Use Only as Access Point" function built-in to them. You must have a separate router, unplugged from the LAN/ISP to start. On your computer, find the subnet mask. (Usually 255.255.x.x) Second, you plug your computer into the router and change the settings for your WiFi (name, password, etc), once they are set it is a pain to re-set them. Third, find the option to clone your computer's MAC address. (You might have to search the help for the router to do this.) (Oh and the reason this works is because it's the outbound/facing MAC address for the router. Your computer sees something else.) Set your router's subnet mask to the mask your found earlier. Then, find the "Use as Access Point" feature and enable it. Plug in your router to the wired internet connection. Connect via WiFi to the router. Your computer should now be connected as if the router weren't even there. Sometimes the other computers still aren't visible. Dunno why :/ But good luck!

--I make no guarantees or warranties about the information above. Change settings at your own risk. Your best bet is to find a nerd friend where applicable.

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