Virtual Adapters
 

I know it is possible to have one ethernet card run as multiple adapters. As far as I've heard, they're called "Virtual Adapters".

I also know that its quite trivial to change the MAC address on the ethernet card.

What I was wondering is: Can I put 2 and 2 together? Can I have one physical ethernet card, take multiple IP addresses, each having its own MAC address?

I don't see why not, as most adapters can run in "promiscuous" mode, picking up packets for every MAC address, so it shouldn't be difficult to configure the adapter to pick up packets for a specific, configurable MAC address.

However, the potential risk you run is that the MAC address you choose conflicts with a pre-existing MAC address on your network. It's the same principle as IP addresses - you don't go picking one at random because there's a chance someone else may be using it.

I can't see why using "virtual adapters" with multiple IP addresses wouldn't be sufficient for your needs - the MAC address is something the administrator should never have to deal with anyway - it's only there as a way of resolving hardware to IP addresses. There's no benefit to having multiple IP addresses on separate MAC addresses or on the same MAC address if it's all going through the same adapter.

Yes there is =P

My school (Michigan State Univ.) gives as many IPs as you like, but they are associated by MAC.
So you can register as many "computers" (or ethernet cards) as you like, each one gets its own IP (given on its first DHCP), however, the upload for each of these IPs is rate-limited to 10Kbs by IP/MAC.

They limit to 10kbs as an easy way to kill P2P. However, it also kills legit things like running a website (which I do).

By having one adapter (which isn't nearly being used to its 10/100 potential) having multiple IPs/MACs, I can do a round-robin DNS, and easily run a website. By having each sequential request coming in a different IP, I can divide the load between multiple 10kbs upload streams. Obviously, for a 1meg file, its not going to help, but when dealing with a website (which is likely to be 15-20k), it would help significantly.

Does anyone have any quick guides/tutorials on how to setup virtual adapters?