TCP and IP were developed by a Department of Defense (DOD) research project to connect a number different networks designed by different vendors into a network of networks (the "Internet"). Transmission Control Protocol/Internet Protocol (TCP/IP) is now considered the suite of communications protocols used to connect computers on the Internet. There are two primary protocols TCP and IP. TCP enables two hosts to establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees that packets will be delivered in the same order in which they were sent. IP specifies the format of packets, also called datagrams, and the addressing scheme. Combined with TCP, IP establishes a virtual connection between a destination and a source. Each computer looking to communicate using the Internet must enable TCP/IP in their respective operating system, Windows, Mac or Linux.

There are normally four addresses related to TCP/IP protocol. They are IP, Subnet Mask, Gateway, and DNS Addresses.

IP address is unique on each network device.

Subnet Mask Address decides which subnet the IP address belongs to.

Gateway is a device that acts as an entrance to another network; if you have a Router for Internet sharing, each network computer/device normally has the Router's IP address as Gateway IP address.

DNS is an abbreviation for Domain Name Server, which is an Internet server that translates domain name (i.e. www.trendnet.com) to IP address. Without the correct working DNS, you are not able to go to web page by entering the domain name in the web browser (Internet Explorer or Netscape).