I am trying to set up a hidden wifi network in my dorm to connect my wireless devices (2 laptops, chromecast, hue lightbulb, and a printer). I want to use my school's internet service so I must give them a MAC address to get my device to connect. I need a router that will push all of the data to the school's network through one MAC address so I don't have to set up each device with them. Any suggestions?

  • Yes, I am going to do that, but some routers (Apple Airport for example), push traffic through each device's MAC address. I want a router that will only push through its own. – Lee Aug 17 '14 at 20:04
  • Routers handle your need fine. Most will even let you spoof the routers MAC address. – Tyson Aug 18 '14 at 1:18

When you talk about a "router", you are talking about a device that makes multiple things.

  • One of them is "switching", that is, transmitting frames between machines on your network;
  • Other is "routing", that is, transmitting datagrams between machines on your network and machines possibly on other networks (through the Internet, for example).
  • Other is "translating addresses", typically called acting as a NAT box.

There are others, but they are not relevant to this discussion.

When you have a device that reveals the network's MAC addresses, you probably have just a switch, that knows nothing about IPs. This also means it knows nothing about NAT, since it makes no sense to have NAT but no IPs.

You don't need NAT to avoid revealing the MAC addresses of the network. Once the packet goes from your router to a different router (i.e. your school's), it's always your router's MAC address that is revealed.

However, you may have a different limitation, that is your school only allowing you to have one IP address. There is another thing a domestic router does: giving out IPs, through DHCP to your local network. But if you only have a router, it's your school that needs to give IPs, and they may have restrictions on that.

This is to say: the best way to do what you want is to 1. use only one IP, and 2. use only one MAC address.

This can be done easily - use a domestic router. It will do NAT by default, thus using only one IP from your school, and since it is a router, it will also use only one MAC address. Profit!

By the way: since I'm familiar with a university's network infrastructure, there is also another thing for you to keep in mind: you may need to ask for permission to run a wireless network in your dorm. When we find random unauthorized wireless networks, we track them down and we can confiscate the equipment (although we don't usually do that, but sometimes - especially when there's nobody around to take responsibility for it - it happens).

Use cables, or ask for permission. Avoid doing that covertly, because if your school already has a wireless network deployed, it will eventually find you, especially when someone complains about interference.

  • Thank you so much, is there some way I can prevent interference? – Lee Aug 22 '14 at 14:17
  • You can see in what channel are the school's wireless networks, and choose the farthest channel available from it. That reduces interference (it never completely avoids it). But strong interference is just a way you will get noticed; the problem isn't in the interference, it is in you running an unauthorised wireless network. – Valmiky Arquissandas Aug 23 '14 at 2:02

Every router that uses NAT will label the packets with its own MAC address.

  • Isn't that only for IP addresses, not MAC addresses? – Lee Aug 17 '14 at 20:17
  • @Lee, no MAC addresses are actually only addressable on a single network. They're never routed, and therefore never cross routers. The router will always use its WAN MAC address when sending frames on the network. Now, many routers can "clone" a computer's MAC address, so your router may be using the same MAC as your computer, but both interfaces (the router WAN & your computer) have the same MAC. This works because the WAN and your computer are on different networks. – heavyd Aug 17 '14 at 23:32

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