A Brief Overview of IP Addresses

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An IP address (Internet Protocol address) is an assigned numerical label that is used to identify Internet communicating devices on a computer network. Think of it like this: An IP address is to a computer what a telephone number is to a house. Each computer or house can stand alone without its respective IP address or telephone number. However, if you want to be able to communicate with people in other houses from within your house, you will need a telephone number. In a like manner, if you would like to communicate with other computers from yours, you will need an IP address.

Technical Facts about an IP Address

  • An IP address is a set of four numbers divided by periods
  • The numbers of an IP address range from 0 to 255

In more technical terms:

  • An IP address is a 32 bit binary number that is divided into four sections by periods
  • Each individual set of numbers in an IP address is called an octet
  • There are four octets in an IP address and each octet is 8 bits
  • An octet can range from 0 to 255 in value. (255 is the largest number that you can represent with 8 bits)

Internal vs External IP Addresses


If you are using a home router then you likely have both an External and Internal IP address.

Your External IP address will be issued to you by your ISP (Internet Service Provider). Because an IP address acts as identification number, no two computers on the Internet can have the same External IP address. Your External IP address will be the IP address that is used to contact your computer by the outside world.

Everything connected on your side of your router is in your local network and is designated a unique Internal IP address. In most cases, Internal IP addresses are issued by your router, but you may set a static IP address for the nodes in your local network. For more information on how to set up a static IP address click here.

There are some IP address ranges that are commonly used for internal networks. Here are a few examples of what these addresses look like:

  • 192.168.x.x
  • 10.0.x.x
  • 10.1.x.x
  • 172.x.x.x
Where x can represent any number from 0 to 255.

Static vs Dynamic IP Addresses


Dynamic IP addresses are IP addresses that are vended by a router to a node when necessary. As their name would suggest Dynamic IP addresses are not fixed and are subject to change. Dynamic IP addresses are a handy network function but they can cause problems when trying to do more advanced networking proceedures like port forwarding. If the IP address to which you port forward changes, then your port forwards no longer work.

Static IP addresses are unchanging IP addresses that are assigned to a network node. Static IP addresses will never change. When using Static IP addresses you lose a small amount of plug and play functionality, but you gain reliability. We have a complete set of guides to show you how to set up a Static IP address located here. We even offer free software that will set up a Static IP address for you.

Please note that for almost all purposes regarding port forwarding you will only need to set up a static Internal IP address.

If you have questions, please use our forum as an information source. There are many knowledgeable people there who will be happy to answer any questions that you might have.

Jason Bauer

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Jason Bauer is an owner and programmer for Portforward.com. He's available on Google+, twitter and facebook, and you can find more of his articles in the Guides section.