IP Address Confusion

dublad23

Hi Guys

I'm having a bit of confusion with my IP address.

I checked it today randomly @ findmyip.com and it gave me what my IP Address is. This was on my Laptop

When I check it on my Desktop I get the exact same Ip address

Surely these should be different as they are different computers?

We use the same wireless connection - I have wireless built in on the laptop and the desktop has a router??

Also we are with BT but when I check the IP location and provider it says Connecting through : IRELAND ON-LINE BROADBAND CUSTOMERS which i dont think is BT

Can anyone help me / advise

Much appreciated!

Shiva

dublad23 wrote:

Hi Guys

Surely these should be different as they are different computers?

Your broadband router is using Network Address Translation, which, without getting too technical, means it makes anything on your local network that connects to the Internet through it appear to have one IP address - the IP address of the router.

Also, AFAIK, BT bought out Ireland On Line awhile back - they may still be using the Ireland Online identity for some things.

dublad23

Ah so would it be different then in reality - Would websites register my IP as being different then if I used my laptop and desktop.

When I check my IP Address through Start - Run - CMD - IPCONFIG/Release it shows as completely different to findmyip.com

I take it findmyip.com is the router (internet connection) and the above is the actual IP of my laptop.

What would register on sites?

Sorry for the silly questions!

feylya

Think of like this - your house has one address but many people live there. Companies send mail to one address but it still gets to the right person. Same with ip address. There's one ip for the house but it's broken up internally. Websites would only see the external ip.

dublad23

Thank you Shiva btw - I forgot my manners

Shiva

dublad23 wrote:

Thank you Shiva btw - I forgot my manners

You're welcome. Invoice is in the post

Shiva

Using ipconfig to find your IP address would indeed show a different address to findsmyip.com - here's why, in basic terms :

Each computer on your network has a unique IP address. Lets imagine they have addresses that fall within the range from "192.168.1.1" to "192.168.1.254"

So lets also imagine that they are "192.168.1.2" and 192.168.1.3"

Your router will also have a unique IP address from that range - lets say it has "192.168.1.1". This IP address will be what's known as the "gateway" address for your two computers - When they want to access something on the Internet (like a webpage), they will know that the resource they are looking for is not on your local network (through the magic of DNS - which is another lesson for another time ), so they will use your router as a gateway to the Internet to get at that resource.

Your router, as well as having an IP address in the same range as your local network, will also have a public IP address, which is the one that is visible to the Internet-At-Large. The router receives the request from your computer, and routes it (hence the name) to the Internet. It receives a reply (the webpage you are looking for) and again, routes it back to the computer that made the request.

The public address on the router is the one that registers on the web server you are accessing.

And they aren't silly questions - you're asking basic networking questions to expand your knowledge of how your system connects to the Internet, and that's always something to be commended

When you begin to understand how it all works and fits together, you start understanding how to secure your network from outsiders with nasty intentions, and why its so important.

dub45

Wise man say 'The only silly question is the one not asked!'

Another analogy (along the lines of Feyla's above) is to think of all the apartment blocks everywhere which have many, say, sixth floors and apartment no 3's for example - but they are uniquely identified by the main address of the apartment block which is visible to the world at large.

runswithascript

Just finished studying a module on NAT and PAT when I stumbled across this thread. Nice to see I'm not the only one!

'NAT - The saviour of private IP addresses'