Your computer's wide area network (WAN) IP address is:
This is the address assigned to you by your ISP (internet service provider) and is unique to your computer. Typically, if you are on a dial up connection, this address will change each time you connect to the internet. This type of connection is called a dynamic IP address. The IP is given to your computer from a batch of available numbers at the time you connect.
DSL and cable modems connect in the same manner, obtaining a unique WAN IP address when they connect. Since DSL and cable are normally "always on", your IP address may not change for months. Your IP address may change only if you change your connection password or disconnect for an extended period of time.
Another type of connection for dial up, DSL, or cable is called a static IP address. This is a requested option at the time you enroll with your ISP. There is usually an additional charge for a static IP address. The advantage of static over dynamic IPs is that you receive the exact same address each time you connect. If you are hosting any service on your computer (web pages, FTP server, etc.) a static address allows your computer to be located easily at all times..
ROUTERS, INTERNET SHARING AND LOCAL AREA NETWORKS
If you are connecting through a router, the IP address above is that of the device your are connecting through. A router can be used to connect one to several hundred computers in a residential or office environment. The router connects to the internet in the same way an individual computer does, and then "shares" the connection with the computers that are connected to the router. If you have several computers in your home and have DSL or cable, a router can allow them all to use the internet simultaneously with only the one IP address. Routers connect each computer to a LAN (local area network) though a RJ45 jack on the back of your computer. Another advantage beyond internet sharing between computers on the LAN is the ability to share other resources such as files and printers.
The router is configured with your user name and password (provided by your ISP) by typing a LAN address into your web browser location bar. A web page that is imbedded in your routers software appears and allows you to easily program information and router functions. The router will also play "traffic cop" on your LAN by assigning your computer (and all additional LAN computers) a unique LAN IP address. The router function that assigns your computer a LAN IP address is called DHCP (Dynamic Host Configuration Protocol). Your LAN IP address is different than your WAN IP address. The LAN address is typically 192.168.1.xxx. "xxx" will change and be unique for each computer on your LAN.
Wireless routers connect computers without running CAT5 (category 5 cable that contains 4 twisted pair wires) or similar cable throughout your home or office. A wireless card is installed in your computer or laptop and the connection is made to the router through antennae on the card. Wireless technology is typically called WIFI or 802.11. Wireless speed and stability is constantly changing. Currently 802.11G is the fastest technology..