IP address and geographic location

This is a dumb question , but I need to know, so here it goes.

IP addresses can be used to identify geographic locations. Assume I buy a computer in the US and then use it there for several months. Presumably the machine's IP address will indicate my geographic location as somewhere in the US.

Then I move to Canada and use the same machine there. At this time, will the IP address change somehow to indicate my new geographic location as in Canada, or will it still show the US location like before?

Thanks indeed.

 

Your web IP address is assigned to your machine by the ISP through which you are accessing the internet at the time. Where you purchased your computer has no bearing.

 

Ditto comments above - geolocation is a pretty interesting area and it's not difficult to be correct "most" of the time, but it's very hard to be accurate all of the time, and with proxies/etc., exactly where you are is kinda hard to define sometimes.

I whipped up a little script a while ago that does a half-assed job using the IPFree Perl Modules - see my IP-Country locator

 

Thanks to both of you.

Hi TheDoug,

I know the place of purchase is hardly relevant to the IP address; what puzzles me is whether a machine can have multiple IP addresses, i.e. whether the IP address changes as geographic location / ISP change.

I have heard one computer can only have one IP address, assigned to the machine by its ISP, as you have indicated. When its geographic location / ISP changes, is the computer assigned a new IP address, or is it stuck with the old one?

Many thanks indeed.

 

ISP's have a defined range of IPs, so if their IP changes (which it does with dialup, usually, you get a new one on each connection) it will be within the same range, so you could find out their ISP.

However, it is possible to track a machine down using a MAC address... but getting a MAC address is rather harder than an IP. A MAC address does not change on the NIC (network card/modem) ever, unless the hardware/firmware is altered somehow, and it is unique to the NIC. You can spoof a MAC address, but its tricky because you need to make sure it doesnt conflict with a current MAC somewhere else, and give the game away.

Usually these are most noticable in LAN networks in conjunction with ARP Tables. This basically lets all the devices know which MAC address is at what IP, so the packets get labeled correctly and get to their destinations. There is such a thing as an ARP Inject, which changes a value in this table so packets directed towards a specific IP (say, 192.167.0.2) go to a different machine. The primary use for such a thing is to "sniff" packets from the desination machine, and then bounce them on. i.e. all data going to 192.167.0.2 goes to another machine before reaching its final desitnation.

In relation to your objective, MAC addresses can be tracked down to manufacturers, perhaps even place of sale. However you would need quite a bit of co-operation with the manufacturers, ISPs, telecommunication companies and the authorities in order to get this far.

 

In addition to goldfish's excellent comment above, I'll add that on the "multiple IP addresses", a machine have have more than one Ethernet interface in which case it would have different IP addresses (trunking/multi-pathing usually does too) ... and even with a single interface, you may "assign" more than one IP address to it.

All of this applies mostly to Corporate/business network and rarely comes into play for folks at home, but I just thought I'd chime in with a few more facts.

 

Many thanks indeed.