"Do you think it is possible ?"

Yes, it's definitely possible. I, and many others have done it.

"should I consider any thing extra?"

Yes, the ethical and moral obligations you have to yourself and others.

...ain't nobody around here going to help you script-kiddy around anything, so once you show the code you've got, feel free to ask questions related to the specific issues you're having. That way, if anyone here provides code, we'll be confident that you have a legitimate reason for snooping on traffic that isn't yours.