Spoofing an Internal IP Address

Unknown

Is it possible to spoof your internal IP address on a network so that the machine you're making connections with thinks that you're someone else? Combining this with a MAC address spoof, you could basically impose as another computer on the network, allowing you to do all kinds of things without the other machine knowing any wiser. I realize that with tools like Nmap, you can actually use a flag to spoof your IP address when scanning another machine (which is seriously useful), but is there a way to do it for your whole machine and not just for the use of Nmap?

RemadE

At University you tend to tie your IP address with your username/ID so it may be quite tough. By all means you could do it on WiFi but unless you had a fair amount of free IP addresses (internal) then set up a batch file to auto assign an IP between a range. It's just when you connect to the Internet, you have to sign in via your University welcome page. A bit like those you get at a Starbucks etc. When I spoofed the IP of a person who was on the internal network, I could use their details without even logging in as I spoofed their PC.

Unknown

How exactly did you go about spoofing the IP address of another user on your network?

BaconPie

You can just assign yourself a static IP to be the same as the other persons, it's not really 'spoofing'. That'll just cause conflicts though because at the Link Layer it checks against MAC addresses.

What you're probably looking for is ARP Spoofing.

Oh FYI, to assign a static IP on a UNIX variant (OSX/*BSD/Linux) you type:

$ ifconfig <interface> address <ip address>

Fuck knows how you do it on Windows. Check Google for some (RSI inducing) guides.