A Brief Overview of IP Addresses
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 device 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 via DHCP (Dynamic Host Configuration Protocol), but you may set a static IP address for the nodes in your local network.
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. These ranges are private and not addressable from the public internet. They are basically invisible outside of the LAN.
Static vs Dynamic IP Addresses
Dynamic IP addresses are IP addresses that are leased to a device by a router when necessary. As their name would suggest Dynamic IP addresses are not fixed and are subject to change when the lease expires. Dynamic IP addresses are a handy network function but they can cause problems when trying to do more advanced networking procedures 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.
Please note, port forwarding will almost always use static Internal IP address.