IP addresses are used on the Internet and in TCP/IP networks to allow for communication between computers and other networked devices such as printers and copiers. If your computer doesn't have a valid IP address on the right subnet then you will not be able to communicate with other devices on that network. There are public IP addresses used for things such as websites where they need to be accessed by computers over the Internet. Then there are private IP addresses used for internal networks where the devices don't need to send data outside of the network. You can still have a private IP address and send data outside of the network to the Internet by the use of routers and other devices which translated private IP address information to public IP information.
In the world of IP addressing there are 2 main types of IP addresses, static and dynamic. Here we will explain the difference between the two.
A static IP address is an address that does not change over time unless changed manually. It is used when you need the IP address or network location to remain the same consistently. A good example of this is for a web server. If you go to www.google.com you are really going to the IP address of 220.127.116.11. If this were to change suddenly you would not be able to get to Google unless you knew the new IP address or until Google updated their DNS records. Most of the time your servers at work will use static IP addresses as well so you will always be able to access them and so that your network administrators will know how to get to them.
A dynamic IP address is an address that keeps on changing. It is mostly used when having a consistent IP address is not necessary. An example of this would be the IP address your ISP (internet service provider) assigns you when you log on to the internet. You must have an IP address to surf the web but once you disconnect you lose that address. Then the next time you sign on you are assigned a new one. This is done using DHCP. Your workstation at work most likely has a dynamic IP address since there is usually no need for it to have the same IP address all the time. Dynamic IP addresses are leased from the DHCP server for a period of time and then your computer will request a renewal or a new IP address when the lease expires.
For information on how to find your IP address and what type you have click here.