Assigning different IPs to apps without the use of VMs

Question

I'm trying to run multiple copies of a game in the same host but the game checks for your IP before letting you connect. So I'm looking for a way to get around that problem. I've rented VPNs and were using them on VMs. But after learning that there are ways to do it without VMs I am looking for some more information.

What is the correct way here? Should I look into proxies instead? Should I look into routing rules? I tried creating a TAP adapter, tried using ForceBindIP but I couldn't succeed.

edit: I'm on Windows 7

Answer 1

Using multiple IP addresses

You can assign the host multiple IP addresses on the same network interface. Here are some tutorials: Connect to two LAN networks with a single card or How to Quickly Add Multiple IP Addresses to Windows Servers

Next, you need to check that your host is reachable from the outside on all these addresses. You could use something simple like iperf. Open an iperf server with a binding to one IP on your host, and see if it works. Do this for each IP separately.

Now you can use ForceBindIP to bind each instance of your game to one specific IP address.

Using NAT

If you can not or do not have multiple public IPs, using a NAT setup might work. Here your public IP would be assigned to a router that does the NATing. The router would have a private network with the server and the server would have multiple IPs in this network (see above). Now you could assign different port forwadings to each server IP.

For that to work, your game must allow you to change the server port (at least on the client side).