Simple scenario. My internet connection uses DHCP, and my home network uses (static) 10.x.x.x addresses. How do I add a static 10.0.0.x address in addition to the IP provided by DHCP? In linux it's pretty simple: ip addr add 10.0.0.1/24 dev eth0

Not too sure what you mean but If you're using router, you could change the setting for static/dhcp at the router config page. The other alternative is through lan>tcp/ip properties in windows if you're not using router

What I meant, was that I would like to have 2 ip addresses simultaneously on my network adapter: 1 provided by DHCP and 1 static. I don't have a router. Would be interesting to hear how you would accomplish this via TCP/IP properties though, because there is no such setting.

There is a Alternate Configuration in TCP/IP properties, which is used on more than one network. You can configure your Static IP address under it. To do this, please right click Network Adaptor, click Properties, click TCP/IPv4, highlight Alternative Configuration, check User configured, then enter your Static IP address, Subnet mask and Default gateway.Dale

I'm not sure how to be more clear in my question, but I try.. What I would like to have, is being connected to the internet (via IP provided by DHCP) and to the other PC in the room using 10.x.x.x addressing AT THE SAME TIME. So the DHCP and static IP's should be working SIMULTANEOUSLY. This is not what alternate configuration is about. In Windows XP this was achieved by using DHCP in the TCP/IP properties, and adding additional static IP's for the network interface in the registry. The registry method haven't worked since Vista.