IP addresses
 

Does anyone understand how IP addresses work? Please excuse my stupidity and help me understand!

As most of you know, I'm currently a finalist in a contest (see 'I'm a Finalist' thread if you have no idea what I'm talking about). There was a problem in their system so now they're limiting votes to 1 per IP address and they're going to eliminate multiple votes from an IP address.

I know when you reconnect to the internet you get a new IP address, but how many IP addresses would an internet service have? Are they indefinite or will they just rotate and run out?

If my neighbor uses the same internet service I do, could they potentially get the same IP address as me when they connect at some point?

Where my husband works they have thousands of computers but they're all on 1 IP address? How does that work?

Thanks for listening to my million questions!!

I think each computer gets its own IP address (so, essentially, one email address per computer), but I'm not sure. I've paged mightymike as he'll be able to explain it. :)

If you're using dial-up, IP addresses are assigned from a pool of numbers on connection to the ISP. If you're using DSL, cable modem or FTTP (fiber to the premises), generally you will have a static IP address assigned to that port, though it is randomly selected by the server on connection. For additional security, the ISP will 'marry' the connection to the MAC address (machine address something-or-other... I gotta hunt down my trusty computer terms dictionary to get the correct definition), which is generated by the network interface card or router in the computer. You will have to release the IP and MAC address in order to get a new assigned IP address. (It gets really technical afterwards, so I won't bore you with the details.)

Your neighbor will have a different IP address from the pool of assigned IP numbers from your ISP.

At work, a small number of IP addresses will work for the company; it's the router that allows individual computers to communicate with the Internet through the server.

Hope this helps.

Most residential cable modem / DSL services actually use dynamic IP addresses, not static. Your IP address can change at any time, though it seldom does. Because they change so seldom, for your purposes, you can consider them static.

At work, it depends on how the network is set up. The IP address where your husband works is pointing to a router. To the outside world, it looks like all network traffic generated at his office comes from one IP address. (So, ask your husband to ask his coworkers to vote for you, but from their home machines.)

Good luck :)

AlphaSigOU has it nailed so I'll elaborate on it a bit with some (useless) info that you'll never need to know. The MAC address stands for Media Access Control address.

It's possible to change your IP address to foil the voting system and take over the world. The commands vary depending on your operating system and rely heavily on the type of internet connection you are using. If you're on dialup, there is a solid chance that you'll get a different IP address each and every time you connect. The problem is that your connection gets funnelled through your ISP (Internet service provider) to another IP address. So no matter the IP address your computer gets, to the world, you'll always appear to be the same person. One easy way to check the IP address you're seen on the Internet as is to go to http://www.whatismyip.com. So long as that IP address shown on the website is the same, then you'll only be able to vote once.

Now, let's assume that you're using some type of broadband connection. *Sometimes* you can change your IP address by going to a command window by: Selecting Start > Run > type: cmd > select OK. You will now have an old school DOS window on your machine. At the prompt type: "ipconfig /release" and you'll see a bunch of "stuff" appear on your screen. When you get back to the prompt type: "ipconfig /renew" and you should pick up an address again.

Chances are that you'll get the same address. This is because your connection is leased to you from your broadband service provider - generally for 7 days - through a process called DHCP (which I won't explain). When the halfway point of your lease expires, your ISP and your computer will attempt to renew the lease. So long as your computer is on (or router) you will be auto renewed.

Shew, okay. Getting back to the point. If you released and renewed your address and got the same one, you'll have to turn your computer off for at least half of the duration of your lease before you have a chance at getting a new address. If your address is not renewed, it goes back into that pool that AlphaSigOU mentioned and can be taken by another user.

Anyway, hope it helps and if it didn't maybe it'll help someone else later.

Mike

Wow, this is way more complicated than I thought! Thanks everyone! I'm not sure if I understand it all, but I'm getting there.

I was told by a few people that each computer would have its own address. BUT we have a DSL line and I've noticed before that every time we disconnect the modem and plug it back in we get another address.