IP addresses are of prime significance in the understanding of the functionality of Internet. To skip the details and being simple, and IP address is a unique address assigned to any machine connected to the Internet. This signifies the fact that if you have the address of any machine, you are in a better position to commence the use of any feasible exploit, gain control over the machine and then use it to your advantage.
So, where do we begin from? First of all, you have to identify a particular target. It should be a person you happen to know personally. If the person is not in your close social circle, you will have to impersonate one of the victim's friend.
Now here is how the simple way stands:
1>>Add the victim on an IM.
2>>Tell them that you have this very important file eg. a picture of their's which you want to send using IM. If you say it the right way, there's no reason why the person would turn this down.
3>>Now before sending the file, open the command prompt in the background and type "netstat". It shows you all the open connections on your PC.
4>>Send the file and wait for the victim to accept it.
5>>As soon as the person accepts it and the file transfer begins, go to the command prompt and type "netstat" again without quotes. You will again see something like this:
Active Connections
TCP digital-venom:4046 80.252.110.146:4661 SYN_SENT
TCP digital-venom:4047 60.28.197.35:28221 SYN_SENT
TCP digital-venom:4048 219.239.90.172:28221 SYN_SENT
TCP digital-venom:4049 72.51.37.237:8899 SYN_SENT
TCP digital-venom:4050 66-199-250-170.reverse.ezzi.net:8911 SYN_SENT
Now compare this reading with the one you got before. The IP address newly added to the list is the IP address of your victim.
Note: Some third party software eg. Limewire is known to interfere with the connections established through an IM, specially MSN Messenger. Keep this in mind. :):)
