Time and time again, newbies have asked how they can change their IP address. Even more often, people give them the incorrect answer. Hopefully this guide will shed some light on how IP addresses work and subsequently, how they can be modified. What are IP addresses? IP addresses work similarly to real life addresses (e.g. "101 Main Street") in computer networking. The Internet is a big place and web servers need an address to uniquely identify where they should send information. This is your IP address. IP addresses have the following format: #.#.#.# where "#" represents an integer between 0 and 255 (inclusive). Every single computer connected to the Internet has a unique IP address identifying them. Now, its not as simple as that. They're are two types of IP addresses: static and dynamic. Static IP addresses do not change (hence the name static). These are particularly useful if you run a server of some sort where clients would like to connect to the same IP address without worrying that the address will change. Dynamic addresses are the exact opposite, they change from time to time (the length of time could be anywhere between every few days to every few years depending on your ISP). This is useful and in some cases necessary because there simply aren't enough IP addresses to go around. Thus they are dynamically allocated to computers on an as-needed basis. Typically, IP addresses are dynamic when you get a connection with your ISP. Getting a static IP from your ISP usually costs extra money. Local IP addresses Ok, the concept of having a local IP address is usually what confuses people. If you connect to the Internet via a router, each computer technically has two IP addresses. One is the one I talked about above which identifies where you are on the Internet so web servers can send you information. The other is to identify where you are on your local network. The local IP typically has the following format: 192.168.1.#. It may vary a bit from router to router, but 95% of the time its like that. If you have a router, every computer is part of a Local Area Network (LAN) which is a group of computers and hardware (printers, etc) connected by a router. When you visit a website, your computer tells the router which in turn tells the web server to send information back. The information is then sent back to the router which is relayed to your computer. Here's a schematic diagram: Code (Text): Your computer --- Router --- Internet Notice that you never directly connect to the Internet. In other words, no web server ever sees your local IP. Instead, they see your network IP which is assigned to your router. If multiple computers connect to the Internet, its the router's responsibility to relay the information to the correct computer on the LAN. Summary All computers connected to a network are assigned a unique IP address to identify you. If you have a router and thus connected to a Local Area Network, you are assigned a local IP address to identify you on the network and the router is assigned an IP address to identify the network's loaction on the Internet. Web servers never see your local IP. Changing your IP Address If you are connected directly to the Internet via a modem or a cable: Go to Run (Start > Run or Win+R) Type "ipconfig /release" (sans quotes) and then enter Type "ipconfig /renew" (sans quotes) and then enter Alternatively, if you shutdown and restart your computer, you can skip the 3rd step. If you are connected via a router: Turn off or disconnect your router Wait some period of time (depending on the ISP, this could be anywhere between a few minutes and several hours, personally I do this overnight) Turn it back on Make sure you check to see if your IP has been changed. If not, you probably have to turn off your router for a longer period of time. Some Other Information Proxies Proxies are computers that hide your IP by acting as intermediaries between you and the Internet. Here's a schematic of how they work: Code (Text): Your computer --- Router --- Proxy Server --- Internet Thus the web server connects directly only with the proxy server and thus never sees your IP address. Here's a wonderful proxy guide by marlene if you wish to learn more: tech-guides-f94/proxies-a-newbies-guide-t4263.html IPv6 The IP address formats that I have given above only apply if you are using IPv4 addressing (which the vast majority of people do). Since the number of people on the Internet is rapidly increasing, we are running out of available addresses. The new IP address called IPv6 solves this problem by allowing for many many more unique addresses (2^128 to be exact). However, this hasn't been widely adopted yet. MAC Addresses MAC addresses are uniquely identifiers assigned to network cards (both ethernet and wireless). These are supposed to be permanent and unique identifies (you can't change them) though that's not entirely true (I'm not going into details here). You typically don't have to worry about these addresses since they are only really used in LANs and usually for security purposes. They are never sent to any server on the Internet. A MAC address looks like this: XX-XX-XX-XX-XX-XX (12 hexadecimal numbers) DNS Servers All web servers (websites) also use IP addresses to identify themselves. However, I don't think anyone would like to remember the IP addresses of website they go to. Thus the clever designers of the Internet created something called the Doman Name System (DNS) which allows people to uniquely identify web servers using a domain name (e.g. http://www.google.com or http://www.neofriends.net). DNS servers serve as phone books which look up the IP address of a web server when supplied with a domain name (these have to be registered for a certain amount of money). You can find the IP address of a web server by pinging (in the console, type "ping http://www.neofriends.net") or tracerouting them ("traceroute http://www.neofriends.net").