What Is IP address ?

The internal, LAN-IP address is normally set to a default, private number. Linksys routers, for example, use 192.168.1.1 for their internal IP address. D-Link and Netgear routers typically use 192.168.0.1. Some US Robotics routers use 192.168.123.254, and some SMC routers use 192.168.2.1. No matter the brand of router, its default internal IP address is listed in the manufacturer's documentation. Administrators have the option to change this IP address during router setup or at any time later. Unless someone manually changes it, however, this private LAN-IP address remains fixed. This address can be viewed and changed from the router's administrative console.

Locate Internet IP Address

Knowing the Internet Protocol (IP) address one has to the outside world can often be useful for various purposes.
If you need to setup a direct IP connection over the internet, you need to know your IP Address as seen by others on the internet.

Find IP Address if Computer or Router

• If you use router between your computer and the internet, your public IP address is the same as the public ip address of your router. Whether your router is cable, wireless, linksys, netgear or whatever does not matter.
• You can connect multiple systems to your router, e.g. laptops, xbox 360, play station, media center and other computers.
• Your router can make all connected systems share the same IP address. The router handles this by tracking outgoing and incoming TCP and UDP packets. It can do so by assigning port numbers to all outgoing traffic and compare these to incoming traffic port numbers.
• If your ISP has given you a static IP address it should be the same each time you connect to the internet. If you have a dynamic IP address it should change when you disconnect and connect to the internet.
• The special IP address 127.0.0.1, also called localhost, refers to your own computer.

What Is the IP Address of a Router?

The external, WAN-IP address of the router is set when the router connects to the Internet service provider. This address can also be viewed on the router's administrative console. Alternatively, the WAN-IP address can be found by visiting a Web-based IP address lookup service like http://checkip.dyndns.org/ from any computer on the home LAN.

Another way to identify the public IP addresses of routers, involves executing a ping ortraceroute command. From inside a home network, the (DOS) command "ping -r 1" will send a message through the home router that will cause its IP address to be displayed. For example, "ping -r 1 www.yahoo.com" should result in a message like the following displayed on the command prompt:

Reply from 66.94.230.43: bytes=32 time=294ms TTL=56

Route: 209.179.21.76