For example, I have a linux distribution installed in Virtual Box. I want it to have a virtual adapter with its own IP, without having a network created between my host machine and my virtual machine. I need my VM to act as a real machine in the wireless network I'm connected to. How can I do this in Virtual Box using the adapter options?
Use a 'Bridged' network connection. this will give you an ip that is on the same subnet as your physical network, and does not put a NAT barrier between the VM and the other hosts on the network.
you can map the bridged adapter to an unused nic on your system, or share the hosts nic, if you don't want to run another network line.