Introduction to Computer Network Security

Protect Your Equipment and Data

Padlock on top of keyboard
Computer Network Security. Epoxydude / Getty Images

With all of the vital personal and business data being shared on computer networks every day, security has become one of the most essential aspects of networking.

No one recipe to fully safeguard networks against intruders exists. Network security technology improves and evolves over time as the methods for both attack and defense grow more sophisticated.

Physical Network Security

The most basic but often overlooked element of network security involves keeping hardware 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 broadband routers in private locations, away from nosy neighbors and house guests.

Tip: On that note, if you can't keep your physical hardware away from nearby snoops, you might consider disabling information that gives away the fact there even is a device nearby. For example, you can disable SSID broadcast on a router so that devices can't easily see or connect to it.

If data theft through a physical means (i.e. stealing a computer or router) is a concern, one solution is to stop storing the data locally. Online backup services can keep sensitive files stored off-site at a secure backup location so that even if local hardware is stolen or compromised, files are still secured elsewhere.

Widespread use of mobile devices makes physical security that much more important. Small gadgets are especially easy to leave behind at travel stops or to have fall out of pockets. News stories in the press abound of local residents having their smartphones stolen in public places, sometimes even while using them. Be alert to the physical surroundings whenever using mobile devices, and conscientiously put them away when finished.

Finally, stay in visual contact with a phone when loaning it to someone else: A malicious person can steal personal data, install monitoring software, or otherwise “hack” phones in just a few minutes when left unattended. An alarming number of ex-boyfriends/girlfriends, spouses, and neighbors get accused of such acts.

Password Protection

If applied properly, passwords are an extremely effective system for improving network security. Unfortunately, some don't take password management seriously and insist on using bad, weak (i.e. easy to guess) passwords like “123456” on their systems and networks.

Following just a few common-sense best practices in password management greatly improves the security protection on a computer network:

Tip: If you avoid using really strong passwords because they're harder to remember, consider storing them in a password manager.


Even without physical access to the devices or knowing any network passwords, illicit programs called spyware can infect computers and networks. This is typically perpetuated by visiting malicious websites.

Lots of spyware exists. Some monitor a person’s computer usage and web browsing habits to report the data back to corporations who use it to create more 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 is ideal for capturing 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 from 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 through today’s technologies, those methods do protect privacy to a certain degree.