Finding the Owner of an IP Address

While you cannot find the specific owner of an IP address, I'll look at a few tools to see what IP-related information you can get.

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How do I figure out who owns an IP address?

At the risk of coming off as rude: you don’t. There’s a certain amount of information you can get, and I’ll show you shortly, but the level of detail most people want is simply not something that you can get on your own.

Over the years, I’ve received this question repeatedly and for various reasons. Most commonly, it’s from someone who’s being harassed online, and they believe that they have the IP address of the person responsible and now want to track them down.

It’s critically important that you realize that you will not, on your own, be able to get the information you want. The name, location, phone number, email address or any other specific information are simply not available to just any given IP address. Not only can an IP address change or be shared among many computers (and hence people), but the information that you’re seeking is considered private and is protected by the ISP who owns that IP address.

To get that information, you’ll need a legal reason to require it and that typically means a court order of some sort.

However, let’s look at what you can determine from an IP address on your own and a few tools that will help you determine at least the ISP that owns it.

Whois

“Whois” is a service that basically answers the question “who is X” where X is an IP address, a domain name, and several other things.

ARIN, the American Registry for Internet Numbers, is a fine place to start. The ARIN Whois can be accessed from http://whois.arin.net in the upper right corner:

ARIN Whois Search

Enter the IP address you’re interested in and press Return. I’ll use 72.104.186.113 (an IP address that I know to be assigned) as my example:

ARIN Whois Results

This is pretty typical of what you’ll get: information that identifies the ISP who owns the “block” of IP addresses that contains the IP address that you asked about. In this case, the block is owned by Verizon Wireless and includes all IP addresses from 72.96.0.0 through 72.127.255.255.

With a court order, law enforcement would then approach the ISP for more detailed information about who that IP address was assigned to at the time in question.

Also note that it’s possible that the information presented may point you to a different whois server – ARIN covers IP addresses assigned in North America; there are other services for the rest of the planet.

Reverse DNS

In some cases, reverse DNS can be instructive.

DNS is the mapping of a domain name, like “askleo.com”, to an IP address. Reverse DNS does, as its name implies, the reverse: given an IP address, it finds the domain name that has been assigned as the primary1 identifier.

I’ll use a tool from a third-party vendor this time, http://whois.domaintools.com:

DomainTools.com results

You can see that this gives much of the same information that we’ve seen above, namely the ISP who owns that IP address. But there’s an additional tidbit of information.

113.sub-72-104-186.myvzw.com is the domain name that identifies this IP address. This type of domain name is common for IP addresses which have been assigned to consumers and small businesses for internet access. You can see that “myvzw” is an additional clue to which ISP provides this IP address: Verizon Wireless.

Occasionally you may find things in the reverse DNS that might lead you to some additional theories about the IP’s ownership including, perhaps, an actual domain name for an actual web site, or some kind of encoded general location.

GEOIP

Looking at the report from domaintools.com, you can see that it references “United States Newark Verizon Wireless” as the IP location. Needless to say that’s incorrect. It reflects the location of the ISP, Verizon Wireless, but does not actually refer to the location of whatever equipment is connected and using that IP address.

We may be able to get a little closer.

A company called MaxMind, who provides geographic location information based on IP addresses to businesses has a page on which you can test their technology: http://www.maxmind.com/app/locate_demo_ip. Here’s what they displayed for the IP address I entered:

Geoip Results

Here you can see that the scope has narrowed somewhat. The location is listed as “Chattaroy, Washington”.

We’re getting closer, but not much. MaxMind has correctly identified the state where this IP has been assigned. The city of Chattaroy, however, is several hundred miles on the other side of the state from where that IP address is actually in use.

This is common. For most normal, residential or small business connections most of the publicly available information is accurate only to the state. Occasionally, depending on how the ISP has constructed their network, you may be able to get to the correct city or neighborhood. It is possible, just not common, and there’s no real way to know just how accurate the information is when you get it.

IP sharing

Particularly when it comes to web servers and web hosting, it can sometimes be instructive to see what other domains might be hosted at the same IP address and server.

We’ll use http://whois.webhosting.info for this look-up.

A lookup of a residential or other IP assigned for internet access is unlikely to return any results (and in fact, a lookup of 72.104.186.113 returned
none), so we’ll use another IP address – that of askleo.com, 67.225.235.59:

52 Domains!

(This search can be slow – the information in DNS is not optimized at all for this kind of look-up.)

As you can see, it reflects that askleo.com and 51 other domains are on the same server and share the same IP address. (Yes, I have several domains, and host a few for close friends as well.)

If you do this kind of IP lookup on an account at a shared hosting service, you might find that the site shares an IP with perhaps hundreds or even thousands of other websites.

Depending on the type of hosting being used, you may or may not draw conclusions from the list of sites returned. In my case, it’s a fairly safe bet that askleo.com and pugetsoundsoftware.com (on the same server) are related. However, if the IP is shared with hundreds of other sites at a shared hosting location, then no inferences can really be made.

This probably wasn’t what you wanted…

While I’ve shown you several tools that you can use to gather information about an IP address, and there’s a fair amount of information based on the most common questions, I totally understand that it’s still not enough.

Most people want the name of the person who owns an IP address, their physical address, their email address or their phone number. You can’t get there from here. The ISP provides that internet service to someone, it’s true, but they will not release that information, and that information is not available publicly. You’ll need the assistance of the courts, law enforcement, and possibly overseas law enforcement if the IP address is located in another country.

And when you think about it, that’s exactly as it should be.

If the tables were reversed, you really don’t want random people tracking you down by your IP address, now do you?

This is an update to an article originally posted : July 19, 2004

Footnotes and references

1: An IP address can be assigned to many different domains, particularly on shared hosting services. One domain name is typically designated as the primary. For example a reverse DNS lookup on the server hosting askleo.com would actually return you lw3.pugetsoundsoftware.com – the primary name of that server.

There are 8 comments:

  1. Will Bontrager Reply

    Good stuff, Leo.

    An IP address can tell us when the same Internet connection is used repeatedly, such as tracking a browser from page to page in server logs. However, as you said, and contrary to what many hope or believe, tracking down an individual by IP address is nearly impossible.

  2. Steve Burgess Reply

    Looking up UP addresses by Geolocation, I’ve sometimes gotten as close as a couple of miles, and as far as the wrong country.

    I’d also like to highlight something you said. You can get the assistance of the courts by asking a judge to issue a subpoena – but you don’t have to use law enforcement. If you are being harassed online, or some unauthorized person has gotten into your email account, it is fairly straightforward to get a judge to issue a subpoena to ISP to reveal who a given IP address is assigned to at a given time. At least, that’s what attorneys I’ve worked with on computer forensic cases have told me. Law enforcement has far too much to do than to act on a user’s suspicion without evidence of real harm. (May I link to a story about one such case? The Case of the Teacher and the Trickster )

    A fun read. Smile

    Leo
    10-Aug-2011
  3. Snert Reply

    TOR will route your e-mail through various and sundry relay ‘nodes’ (is that the right idea?) so your IP address is anon. So I understand.
    Check it out yourself and see.

  4. Dennis Kelley Reply

    For fun I googled 67.225.235.59

    A couple of clicks later I got:
    (I exchanged some numbers with “x’s)
    Registration Service Provided By: Simple Online Solutions
    Contact:
    Visit: http://simpleURL.com

    Domain name: ask-leo.com

    Registrant Contact:
    Puget Sound Software
    Leo Notenboom ()

    Fax:
    P.O. Box 2xxx
    Woodinville, WA 98072
    US

    Administrative Contact:
    Puget Sound Software
    Leo Notenboom ()
    +1.20677xxxxx
    Fax: +1.20677xxxxx
    P.O. Box 2xxx
    Woodinville, WA 98072
    US

    Technical Contact:
    Puget Sound Software
    Leo Notenboom ()
    +1.20677xxxxx
    Fax: +1.20677xxxxx
    P.O. Box 2xxx
    Woodinville, WA 98072
    US

    Status: Locked

    Name Servers:
    ns1.pugetsoundsoftware.com
    ns2.pugetsoundsoftware.com

    Creation date: 05 Sep 2003 23:57:38
    Expiration date: 05 Sep 2012 23:57:38

  5. pirate22 Reply

    ANYONE RECIEVING A E-MAIL-can they determine which Country it came from.
    Also im “Miffed”that the country that has been tracked keeps throwing up sites in the foreign language-can this be stopped from haappening

  6. Margaret Louk Reply

    I got an add-on for Mozilla Firefox called WorldIP. When you go to a web site it tells you what country it is from, at least it is supposed to. There is a little U.S. flag etc. Very unobtrusive. I would recommend it.

  7. beatrice Reply

    My daughter had a very embarrasing moment, her and her friends were trying to start a blog and decided to send out questionares from an idependent email dedicated to the blog for intrest topics. They received back alot of comments and downloaded them into comment sheets on various topics. When they decided to send out another folloe up report the wrong document with some of these comments that had been received was sent by mistake. One of the comments although it did not mention a name was a little racy and was sent to the person it concerned. That person’s mother had someone trace the email (she sai# and announced the finding with my name attached at a school meeting. I don’t understand how she did this and got my name!! or did this at all?? our service in our home is in my husbands name. From what the girls told me, #i wasn’t at the meeting# she mentioned when the email was set up not sent and showed this on some fancy phone. my name was showed with: #Malito). We have since tried to apologize and say there was no maliciosness behing it, but this person tends to be a mean conspiracy theroist and it is just such a headache.

  8. Mark J Reply

    @Beatrice
    In order to register for an email address, the email provider usually asks for a name and other personal information. If an email is sent out through the webmailer, this name is typically added to all emails sent out. If you use an email program, the name you set up the account with in that program is included in the sent emails. This is a feature, as most people want it that way. If you prefer to remain anonymous, you would have to include a pseudonym.

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