Finding out someone's IP address

[brian52823]

I was asked the other day by a friend of mine on Yahoo IM to give them the first part of my IP address so that they can tell me what my whole IP address is. For example, I told this person that the first part was 172, and they were able to tell me my whole IP address. Does anyone know exactly how this person was able to do it, and can anyone tell me how I can do the same thing? I have no intention of hacking computers since I've never done it before, but I would like to know HOW people are able to invade your system like that so I can know how to defend mine.

 

[Breakerfall]

Easy:
•If you want to know how to defend yourself, DO NOT give away ANY part of your IP

But if you really want to prevent that kind of chat-attacks, you better stop using those programs (icq, yahooIM, Messenger, AOL-IM, mirc) since none of those are secure. (specially icq).

He was able to get your IP probably by using the netstat command on his machine, which shows you all your actual connections to other computers. Since he had the first octect of your IP, he knew what the rest of your IP was.

•NOTE: I don't know how yahooIM handles the connections between clients because I don't use it, but it's known that ICQ establishes direct connection between computers when you start a chat session w/ the other user. MSN messenger establishes chat sessions through the MSN server, so you don't see the other user IP, but there's a trick for that too.

Cya,
chat safe.

 

[WheeDoggy]

do a google search on socks proxies