Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Is there some sort of shared knowledge between ISPs that make them able to see which customer an IP has been given to, no matter which ISP the IP belongs to? I.e. is someone that is an ISP able to see which customer an IP address is assigned to, just because they are an ISP?

share|improve this question

closed as off topic by womble, Chris S Jul 22 '12 at 0:14

Questions on Server Fault are expected to relate to server, networking, or related infrastructure administration within the scope defined by the community. Consider editing the question or leaving comments for improvement if you believe the question can be reworded to fit within the scope. Read more about reopening questions here.If this question can be reworded to fit the rules in the help center, please edit the question.

up vote 5 down vote accepted

No, at least not in the United States or any other country that I'm aware of - ISPs do not communicate in any way with each other about IP assignments within their space; they have the exact same visibility into another ISP's address assignments as any other member of the public.

share|improve this answer

Not the answer you're looking for? Browse other questions tagged or ask your own question.