I have checked my computer IP several times and gotten 3 different IP addresses. Why?

Answer 1

There are two types of IP addresses, static and dynamic.
A Static IP means that you always have the same IP address while a dynamic IP means that your the IP address changes all of the time

Static vs. Dynamic IP addresses...
This FAQ discusses when you need may Static (or fixed) IP addresses (and how many) and when you can use dynamic IP addresses. IP addresses are in increasingly short supply and like many organizations ZyTrax charges for the use of Static IP addresses. The ZyTrax dynamic IP service 'leases' IP addresses for 24 hours - so you need not worry that 'every time' you connect you will have a different IP address.

Definitions

As the name implies Static IP addresses are the same every time you connect. dynamic IP addresses may change each time you connect to the network (e.g. Internet).

When you do NOT need static IP addresses

If you ONLY do things from the following list you do not need static IP addresses.

If you browse the Internet.
If you send and receive e-mail via an offsite server (the normal method).
If you download or upload files.
If you use Instant message services or chat services.
When you need Static IP Addresses

You need one or more Static IP addresses if any of the following are true:

You run one or more Web server's directly on your site that require external access (from the Internet, or Extranet but not typically an Intranet) .
You run one or more E-mail server's directly on your site that require external access (from the Internet, or Extranet but not typically an Intranet) .
You run one or more FTP server's directly on your site that require external access (from the Internet, or Extranet but not typically an Intranet) .
You run any other service or 'Application' that requires external access (from the Internet or an Extranet). Some Financial Terminal Client applications require that you have a static IP address for licensing purposes.
You allow 'incoming' Video Conferencing you may need to use static IP addresses.
How many IP Addresses do you need

The following 'rules of thumb' apply to calculate the number of required IP addresses.

If you run one of any type of server (FTP, Web, E-mail etc.) on site then you only require a single Static IP address. This is because the WarpTwo router allows 'port mapping' for just this situation.
If you run one copy of any application which uses Fixed Port Numbers you only need a single Static IP address.
In all other cases you need as many Static IP addresses as there are Applications or Servers that use the same Port Number.
If you have any doubts discuss then with one of our technical specialists.

Answer 2

Because most Internet Providers have a block of IP addresses that are given out to their subscribers as they log on... dynamically... meaning.. you log on today.. you may be the first to log on and you get thier first IP address.. tomorrow you might be 5th and get their fifth IP address...

Some providers do offer a Static IP address option but these can be quite expensive because it is dedicated to you and they cannot let anyone else use it.

Answer 3

If you are connected to a public ISP this is the normal thing, you get different IP Address everytime you connect. ISP own a range of IP Addresses, they are given to clients randomly everytime they connect (DHCP).

Answer 4

Are you sharing an Internet connection?

When I shared an Internet connection, we used a router and that changed the computers IP at every start-up

Answer 5

Your ISP probably assings you a different IP address every time you log on to the internet!

Answer 6

Your Internet provider may be using dynamic IP addresses.

That would mean your IP goes back up for lease when you sign off and if it has been taken when you come back online they assign you a new one.

Answer 7

DHPC - Dynamic Host Configuration Protocol

IP's go into a pool, and are allocated to users when they authenticate with the internet provider.

if your ip was always the same you would have a 'static' ip.

Answer 8

depends on the time frame between each check. IP address change depending on how they are setup to expire. Once they expire you get a new one.

Answer 9

yes you're using a DHCP is like a dynamic ip address you can see when your ip is gping to expire in the command promp type
(ipconfig /all) and you'll see on the botton when is going to expire..

Answer 10

you might be using shared ip address