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IP Addresses

Question: What is an IP address?

The IT Guy says:
Every computer connected to the Internet has an IP address, which identifies it on the network and allows the computer to both send and receive “packets†of information: Email messages, Web pages, instant message communications, etc.

Most home users who connect to the Internet have a dynamic IP address, which means the address usually changes over time. Your ISP (the Internet Service Provider, or company whom you pay for Internet access) owns a range of IP addresses, and as users either dial-up for an Internet connection (with a modem and phone line) or connect with a high-speed modem (via DSL or cable modem) their computer is assigned one of these IP addresses.

All computers at schools also have IP addresses, but often these addresses are “local†rather than “global†IP addresses. A global IP address may be directly accessible from other computers on the Internet, depending if that computer is protected by a firewall. Local IP addresses, on the other hand, are only accessible by other computers on the local network. From a security standpoint, it is generally safer to have locally assigned IP addresses to multiple computers in an organization rather than global addresses. It is also cheaper, since organizations typically pay for the IP address range they are authorized to use, and there is a finite limit to those assignable IP addresses.

More home users are buying routers and wireless routers to share a high speed Internet connection with multiple computers in the house. In this case, the router is assigned the “global†IP address from the ISP, and individual client computers in the home are assigned local IP addresses.

Next Tip: Domain Name Service (DNS)