find an ISP based on IP?

[Keyser Söze]

i have a website/forum of my own and i got this annoying little bastard that i guess is on dsl cuz he can change his IP quickly, then reregisters, so i want to file an abuse charge with his ISP, but how do i find that out?

[Mada_Milty]

i have a website/forum of my own and i got this annoying little bastard that i guess is on dsl cuz he can change his IP quickly, then reregisters, so i want to file an abuse charge with his ISP, but how do i find that out?

Do a WHOIS (http://www.networksolutions.com/whois/index.jsp;jsessionid=c35ad2c1682186ffffffffb06bfabdcaaf092:vyx8) on his IP to see if the registration information is consistent as he changes his IP. If so, you can report to the ISP listed.

If not, he's likely using a proxy. :(