[BirdOPrey5]

No, it's not illegal to post someone's IP address- but that said people can start a lawsuit over anything, legal or not. He could file a lawsuit for the way you put your shoes on if he was inclined and had the money and time to spend.

That said however you need to make a definitive policy on your forum about information such as IP addresses and email addresses. You need to make sure all your mods are aware of the policy and abide by it.

If you have a terms of service see what it says about sharing information and abide by it. If you don't have an official terms of service now might be the time to get/make one so your users can know what to expect- who owns posts, who has rights to images, what information you may or may not share- a lot of details can be spelled out there.

As for this loser who comes back after being banned- forget about him. IP ban him and order all mods to ban him on site. In the ban "reason" put in some text that attempting to circumvent the ban we be considered abuse of your service and you will contact his ISP to report abuse and/or hacking activity.

**** I'm not a lawyer. My advice/opinions hold no legal authority. *****