How do I find someone's IP address on Facebook?

Answer 1

IP addresses used to be available via a flaw by which Facebook notification emails contained an encoded version of the sending user's IP address. However, as of May 2010, this has been fixed. Therefore, if you have a notification email that was sent before May, that user's IP is available in the email.

Nowadays, the technique is similar to other sites that don't divulge IP addresses -- encourage that user to contact you via some direct means. This could be via email (many emails have the source IP address in the headers), or via an instant messaging client that allows direct connections for, say, sharing files. "MySpace trackers" and "Facebook trackers" are popular and even though some of their source sites are a good place to get a virus, the good ones are effective at capturing the IP address of visitors to the site where the code is posted. However, the profile would have to be public in order to catch it, and you'd have to wait for them to visit, and then distinguish legit friends' IPs from the one you're looking for.

It's helpful to remember that IP addresses are so trivial to forge, and they don't reveal too much information anyway, that getting one is often of little use when someone is needing a confirmed identity behind it.

Although IP addresses are virtually useless for obtaining a solid confirmation of ID (though it is possible through backdoor sites that work similar to the White Pages service) you can cover a wide variety of information which can help solidify a case against someone, if say you or someone you know was a victim of cyber bulling/stalking.

With an IP address you can not only tell who their carrier is, their connection and much more, but you can actually pinpoint where it was send from. Not a direct zoomed in address, but the town, or in the case of a city, township/neighborhood (depending on many didn't privacy variations amongst ISPs) which can be enough to support a case. For example, if you have someone hiding behind a fake account and you have reason to believe it's a particular person, you can do one of two things.

You can obtain the IP of their actual account/computer and then you can obtain the one of the "fake" account.

You can also use the locator tool to narrow it down. If you know someone lives in a particular area and the IP doesn't address match the area, then you can assume that it's most likely not the person you suspected.

While IPs don't give out as much information as a phone number, if the right tools are used and used correctly, it can be just as effective. This is assuming, of course, that the IP address hasn't been forged. In addition, many IP addresses represent proxies or gateways that act as a frontend to many different machines.

If you have a situation of abuse involving Facebook contacts, it is best to report the abuse to Facebook, or to the police.
A person's IP address is not publically available on Facebook. If you have a legitimate reason to know someone's IP address, you should ask them.

Answer 2

It is not possible to find someone's IP address through Facebook directly. Facebook does not provide this information to users. Sharing or accessing someone's IP address without their consent is considered a violation of privacy and potentially illegal.