I post often in a 'flobber chat' on my friend's site. It's easy to see who talks by clicking on their name and seeing their IP adresses. Recently, someone has been posting with my IP address. It is definetly not me and nobody is doing it from my computer. Is it possible they could hack and use my IP address, or steal it somehow? If you can help me, please, that would be great, I would love to get this goon back. :mad:

He can't steal it if you have a fixed IP, but there are ways to pretend that messages are coming from an IP when in reality they are not.

Warning! Technical talk.
http://www.securityfocus.com/infocus/1674

Regards,

Pieter

how do i know if my IP is fixed? and how can i make my system more prone to defend attacks of ip spoofing?

Your ISP should be able to tell you if your IP is fixed, but you stated you recognize each other by the IP addresses, so I assume they are fixed. If you don't have a fixed IP, the IP will be in the same range everytime you connect, but not exactly the same.
If you have the exact same everytime, it is almost certainly fixed.

If the spoofer is using your computer as a proxy, then using a properly configured firewall should stop that.
If he is smart enough to spoof it without having to access your computer, there is really nothing you can do about it except report it and try to get a new IP address.

Regards,

Pieter