A Brief introduction to Computer Network Security

Protect your equipment and data from theft

Padlock on top of keyboard
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Although network security technology improves and evolves as the methods for both attack and defense grow more sophisticated, you should be aware of a few security basics to protect your privacy and data.

Security is an essential aspect of networking, and no single process can safeguard networks fully against intruders; security requires a combination of approaches.

Physical Network Security

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

These measures aren't practical for homeowners, but you should still keep your password-protected broadband routers in a private location, away from nosy neighbors and houseguests.

If the possibility of 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 store sensitive files offsite at secure backup locations so that, even if the local hardware is stolen or compromised, the files are still secure.

Widespread use of mobile devices makes physical security much more important. Smartphones fall out of pockets, are especially easy to leave behind, and sometimes are simply stolen. A few precautions are in order:

  • Be alert to your 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 coworker or acquaintance from snooping when you're out of the room.
  • Stay in visual contact with your phone if 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.

Password Protection

If applied properly, passwords are extremely effective in improving network security. Take password management seriously, and don't use weak, easy-to-guess passwords like “123456.” A few other best practices in password management go a long way toward network and device security, too:

  • Set strong passwords or passcodes on all devices that join the network.
  • Change the default administrator password of network routers.
  • Don't share passwords with others unless absolutely necessary. Set up guest network access for friends and visitors, if possible.
  • Change passwords frequently, especially if you've shared them or they've been discovered.

If you have trouble remembering passwords — which should be the case if your passwords are adequate — store them in a password manager.


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

Spyware takes many forms. Some types monitor a person’s computer usage and web-browsing habits to report the data to corporations, who then 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, logs and sends the history of all keyboard key presses a person makes, capturing passwords and credit card numbers along the way.

All spyware attempts to function without the knowledge of the people using the infected computer, thereby posing a substantial security risk to the computer and the network to which it's connected. 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 your 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.

Privacy protection tools 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. Bottom line: Be careful what you share online and with whom.