Networks are a collection of computers and other hardware and software that interact with each other, so that we can share data, applications, and hardware. Computers in a network may be connected to each other by cables or wirelessly. Wireless networks broadcast over radio waves and can communicate with all computers in the area that can receive the signal. Wireless networks are inherently less secure, because it is difficult or impossible to tell who is nearby listening to your data flying by. Most computers will automatically ignore signals that are not intended for them, but there are programs some people use to store all the data being sent over a wireless network to find password and other private information.
A server does what its name suggests; it provides services for remote computers that connect to it. These remote computers are called clients. Clients access servers and request information or request a task to be performed, such as print a document to the network printer or retrieve a data file.
Often when many files need to be transferred together through a network, they are compressed using a file compression utility like WinZip. This means that the files are stuck together in a way that they are compressed to take up less space than the individual files originally used. This resulting zip file can be transferred faster and easier from one computer to another than the original files. They must be uncompressed or unzipped again before they can be used.
Networked computers that are located near one another, like in a computer lab, are connected via a LAN, or Local Area Network. Networks may also spread over a much broader range. A WAN, or Wide Area Network may span countries, continents or even oceans. The Internet connects LANs and WANs from all over the world. It is a network of networks.
A modem allows a computer to connect with other computers via phone lines or coaxial cable by converting the digital signals inside the computer to an analog signal and vice versa. A dial-up modem connection is a much slower connection, but allows users to connect from more remote locations. There are two types of high-speed Internet connections available for home usage in many areas. Cable modems use coaxial TV cable lines to connect to the Internet, and DSL service connects via existing telephone lines. Both use frequencies that do not interfere with TV or voice service running over the same lines. Cable and DSL modems usually connect to your computer's network port or an available USB port. A router is a device that can be hooked up to a modem to allow multiple computers to share the same internet connection. A firewall is used to prevent unauthorized access to a network resource.
Networks should be protected from unauthorized usage and often require each user to login with a username and password. Passwords should be difficult to guess, long, and contain a combination of letters, numbers, and symbols. A good password will typically not be a word found in a dictionary. A bad password is something like the word "password", your cat's name, or your birthday. Just adding the number 1 to the end of your name does not make it a secure password either. It is a good idea to change your passwords occasionally, but not so often that you forget them.
It is very important to understand that information sent over a network is not secure -- meaning that anyone can see the data. Secure connections are used to encrypt the data sent to make it harder for other people to interpret it. Many times users can specify the level of security used when connecting to a network. The more secure, the better, but it is slower because all of the transactions have to be encrypted and decrypted.
As personal information becomes more readily available, the crime of identity theft has become more common. Protect yourself from identity theft, by keeping your personal data, such as your SSN, passwords, and PINs secret. It is against the law to access areas of a network for which you do not have authorization, regardless of the situation, but you should always be careful about what you transmit over the Internet.