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IP address question

I'm a little ignorant of the way the web works, and I'm wondering if websites can track my visits.  I know they can log the IP address, but as far as I understand that doesn't always mean anything.

I'm on DSL, connected through a Linksys router, and it's IP address is 192.168.1.1 -- I think this is standard, so many people will have this same IP.  When I type ipconfig, it usually shows a different IP every time I boot up my computer, but it always is of the form: 192.168.1.*.

So does this mean they can't track me?  i.e. if I enter my personal info during one visit, and then I clear my cookies and everything, there is no way they will know it is me if I visit again.

Nikolai
Monday, December 15, 2003

192.168.x.x is just your internal address, your side of your router. To find out your external ip address visit: http://www.lawrencegoetz.com/programs/ipinfo/

Matthew Lock
Monday, December 15, 2003

192.168.*.* are local address..

Prakash S
Monday, December 15, 2003

I went to that website and it displayed a different one.  It says though that the address is not accurate if you have a router.

So what does that mean?  Does the IP on that page uniquely identify me or not?

thanks.

Nikolai
Monday, December 15, 2003

google for NAT or Network Address Translator.

Basically, computers behind a nat have internal addresses (192.168.*.* for example) and from the outside people only see the ip of the NAT.  Warning: highly simplified.

Jesse Collins
Monday, December 15, 2003

"Does the IP on that page uniquely identify me or not?"

short answer?  yes, it does.


The long answer is that mostly going from your external ip to you will be a pita, involving extracting info from your ISP regarding exactly who had that particular IP number at such and such a time.

Basically its not overly easy from a practical sense, but theoretically its no harder than looking up a few records.

FullNameRequired
Monday, December 15, 2003

Log onto your router and click on the STATUS page and it will tell you what the IP address of the router (relative to your ISP) is. It's the WAN IP address.

Your computer's address BEHIND the router will be different from this. Websites will "track" you based on the WAN IP address.

WAN - Wide Area Network
LAN - Local Area Network

Your computers is on the LAN created by the Linksys router. Your router is on the WAN created by your ISP.

www.MarkTAW.com
Monday, December 15, 2003

Thanks Mark, that cleared it up.  I didn't know the "namespace" is different.  So I guess since my router is on all the time, the IP never changes, so it does uniquely identify me (well, me and my roommate, since tehre are only 2 people on the LAN)!

Nikolai
Monday, December 15, 2003

It might change from time to time.

First of all, you can set up the router to disconnect after a half hour or so of inactivity, or stay connected all the time. This will partially determine how quickly your IP address cycles.

I'm on DSL and if I want a new IP address, I can just shut off my DSL modem and turn it back on again. The minute or so it takes to connect gives me a new IP address. Just logging off and on via the router doesn't seem to do it. Maybe it's the difference between being connected and being logged in.

Still, even with my router set to stay on all the time, I notice that my IP address changes from time to time.

The only way to know for sure is to check it from time to time.

A quick way to check how websites see you is to visit this page:

https://www.grc.com/x/ne.dll?bh0bkyd2

Or another like it.

www.MarkTAW.com
Monday, December 15, 2003

"It might change from time to time."

it will change (unlessy ou are setup with a static ip), but anyone who cares (and can persuade the ISP to cooperate) will be able to track an ip back to its user from the ISP records.

basically the whole internet anonymity thing has always been overstated somewhat :)

(IIRC its the ip address the RIAA are using to track down those guilty of breaking their copyright license)

FullNameRequired
Monday, December 15, 2003

Definately, your ISP has a record of who used what IP address when. But as far as a website determining whether or not it's your first time there based on cookies & IP address, then it's somewhat more than if your IP address doesn't change.

This won't prevent the authorities from catching you if you do something illegal.

www.MarkTAW.com
Monday, December 15, 2003

Check out:
http://www.ip2location.com/map.asp

To see just how accurate this IP based information can be.

Tal Rotbart
Monday, December 15, 2003

Interesting... it says I'm in San Francisco, and is giving me a latitude and longitude.  Is that the latitude and longitude of the city of San Francisco in general, or is that more precise than that?  How does that work?

Nikolai
Monday, December 15, 2003

It is accurate to a degree. Usually ISP's end of the T1/OC3/etc connection to the Internet backbone is the one mapped.
The longtitude and latitude would normally point to the ISP's switch location.

Tal Rotbart
Monday, December 15, 2003

The Latitude/Longitude were pretty accurate for me.

Latitude & Longitude aren't exact sciences anyway. I remember when GPS was introduced there were stories of, say, Americans who learned that technically they actually lived in Canada based on their latitude & longitude.

Now that the FCC requires all cell phones to be able to be located to within 50 to 150 feet, law enforcement is going around mapping lattitude & longitude to street addresses.

Thanks for the link. It's very interesting.

www.MarkTAW.com
Monday, December 15, 2003

To give you an idea how accurate a degree in latitude/longitude is: for latitude, a degree equals 60 nautical miles (a nautical mile is a minute on earth's surface) or 69 miles or 111 kilometer.

For longitude the above is only true on the equator; for any other latitude you need to multiply with the cosinus of the latitude. At the poles all meridians come together and a degree of longitude is 0 meter.

Roel Schroeven
Monday, December 15, 2003

Sure that works in theory, and of course these numbers are decimalized.

The problem is attaching an latitude & longitude to, say, a street address, or even a state or national border. With GPS, we're finding that our estimates were off.

www.MarkTAW.com
Monday, December 15, 2003

I read recently that most ISPs keep the records of who used what IP address for about 30 days.  The exception was Verizon, who kept those records forever.  (it was in one of those RIAA stories from last month.)

Ran Whittle
Monday, December 15, 2003

"The exception was Verizon, who kept those records forever.  (it was in one of those RIAA stories from last month.) "

Hmmm..Given the ISP's relunctance to cooperate with RIAA, I wonder if they change their policy on how long they keep records...

Mark Hoffman
Monday, December 15, 2003

"Latitude & Longitude aren't exact sciences anyway"

Wrong, I work in the GPS industry and it's a highly precise science (google on "GPS technology" and "GIS Technology"). And I seriously doubt law enforcement is shlepping around town mapping people's houses to lat/lon, because with standard GIS technology plus postal algorithms (e.g. as Mapquest.com uses) you can easily get a street address within a couple hundred meters or less.

And Roel, you can't just use the cosine of the latitude because the earth isn't a sphere. GPS and almost all maps use the WGS-84 earth model which is a flattened ellipsoid with specific regional corrections which can get you within 10m on standard consumer GPS (or <1m on the military band) for map to lat/lon or vice-versa.

Ron
Monday, December 15, 2003

Interesting; the site correctly identifies the ISP, but gets the geographical location 1,500 km out.

It also identifies a proxy in Kiev, Ukraine, which is I presume the spoofed IP address that Zone Alarm gives, unless the Saudis have decided to move their central proxy from Riyadh without telling anybody.

As most of us are unhappy because we can't get DSL with a fixed IP address, then the thread is a little irrelevant, though it is annoying to think that we don't even get anonymity to make up for a dynamic IP address.

Stephen Jones
Monday, December 15, 2003

Ron,

You're right about GPS being an exact science, but map making technology in the past few centuries as our cities and streets were being laid out was not.

Law enforcement agencies ARE going around mapping their neighborhoods because latitude and logitude aren't the way cops think, they need street addresses. I can't tell you where I read this except to say it was in a magazine in a doctor's office, and the city in question was in Florida, I think another one in Massachusettes. They have a guy driving around with a GPS device and marking the GPS coordinates of every intersection.

As far as the accuracy of MapQuest, I honestly don't know anything about how they arrive at the coordinates they give or how accurate the are. Why don't you call up these police stations and tell them they're wasting their time?

www.MarkTAW.com
Monday, December 15, 2003

Hmm. the link says I'm in New Orleans when I'm really in the SF Bay area.

pdq
Monday, December 15, 2003

Mark, all roads in the U.S. are already mapped to within 1m accuracy by NIMA and the USGS, available in digital form (also elevations within 1m, google "DTED"). Nobody would be dumb enough to drive around writing down lat/longs, you can buy them on CD-ROM from the USGS.  Maybe this article you think you read in a doctor's office was about something else, or was from before the early 80's?

Ron
Monday, December 15, 2003

Nope, it was a recent article. Thanks for the info.

www.MarkTAW.com
Monday, December 15, 2003

The ip2location thing isn't always accurate if you're connecting through a proxy.  For example at my previous company (in Munich) my external IP resolved to a proxy in Sweden...

Full name
Tuesday, December 16, 2003

> Nobody would be dumb enough to drive around writing
> down lat/longs, you can buy them on CD-ROM from the >USGS

Depends on the licence costs, if you only want on screen route finding level accuracy for a small area like a city it can be cheaper to just drive around logging the intersections than licence the official dat and recode the data into the format you want.

The UK is one of the most obsessively accuratetly mapped countries but it was cheaper for one company to use satelite photos to make a motorway map than buy the official OS data.

Martin Beckett
Tuesday, December 16, 2003

I was just wondering if I purchase a computer off of a friend, and then proceed to hook it up to my cable modem and router, would I have my own Ip address or will I have the same ip address as the person i purchased it from. I guess my question is, Is it the computer that gives off the ip address or is it my "location", like my house or my side of town...im sorry if this question seems silly but im kind of new to this..thanks for any help you can give me.

Marshall Vincent
Tuesday, March 30, 2004

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