Introduction to Computer Network Security

Protect your equipment and data from theft

Padlock on top of keyboard
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Security has become one of the essential aspects of networking. No one process fully safeguards networks against intruders — security requires a combination of approaches. Although network security technology improves and evolves as the methods for both attack and defense grow more sophisticated, there are security basics that everyone should be aware of to protect their privacy and data.

Physical Network Security

One often overlooked element of network security involves keeping your hardware devices protected from theft or physical intrusion. Corporations spend large sums of money to lock their network servers, network switches and other core network components in well-guarded facilities.

While these measures aren't practical for homeowners, households should still keep their password-protected broadband routers in private locations, away from nosy neighbors and house guests.

If data theft through physical means — stealing a computer or router — is a concern, one solution is to stop storing your data locally. Online backup services and cloud storage sites keep sensitive files stored off-site at a secure backup location so that even if the local hardware is stolen or compromised, the files are still secure elsewhere.

Widespread use of mobile devices makes physical security much more important. Smartphones are especially easy to leave behind or have fall out of a pocket. News stories in the press abound of people who have their smartphones stolen in public places, sometimes even while they are using them. Be alert to the physical surroundings whenever you use mobile devices and put them away when you are finished. If your device supports software that allows you to track the device or remotely erase its data, activate it, and use a password with the device to prevent a co-worker or acquaintance from snooping when you are out of the room.

Stay in visual contact with a phone when you loan it to someone. A malicious person can steal personal data, install monitoring software, or otherwise hack a phone in just a few minutes when it is left unattended. An alarming number of ex-boyfriends/girlfriends, spouses, and neighbors are accused of such acts.

Password Protection

If applied properly, passwords are an extremely effective system for improving network security, but some people don't take password management seriously and insist on using weak, easy-to-guess password like “123456” on their devices and networks.

Follow a few common sense best practices in password management to greatly improve the security protection on a computer network:

If you avoid using strong passwords because they're harder to remember, store them in a password manager.


Even without physical access to a device or knowing any network passwords, illicit programs called spyware can infect computers and networks. This happens when you visit malicious websites accidentally or through a link in a phishing email.

Lots of spyware exists. Some monitor a person’s computer usage and web-browsing habits to report the data to corporations who use it to create targeted advertising. Other kinds of spyware attempt to steal personal data.

One of the most dangerous forms of spyware, keylogger software, captures and sends the history of all keyboard key presses a person makes, which captures passwords and credit card numbers.

All spyware on a computer attempts to function without the knowledge of people using it, thereby posing a substantial security risk. Because spyware is notoriously difficult to detect and remove, security experts recommend installing and running reputable anti-spyware software on computer networks.

Online Privacy

Personal stalkers, identity thieves, and perhaps even government agencies, monitor people’s online habits and movements well beyond the scope of basic spyware.

Wi-Fi hotspot usage on commuter trains and automobiles reveal a person’s location, for example. Even in the virtual world, much about a person’s identity can be tracked online through the IP addresses of their networks and their social network activities.

Techniques to protect a person’s privacy online include anonymous web proxy servers and VPN services. Though maintaining complete privacy online is not fully achievable, those methods protect privacy to a certain degree.