How can I secure my internet connection?

Do you have an "always on" Internet connection? It's easy to think that no one could possibly be interested in your personal computer, but that's simply not the case. Having a fast Internet connection that's "always on" when you want to surf the Web is great for you, but it's also great for hackers from around the world who sweep through thousands of random IP addresses looking for computers that they can exploit. And what they can do is really quite scary. Without any visible sign or warning, hackers can infiltrate your system to obtain personal information about you or to use your computer to disguise themselves when they attack other computers.

CERT/CC on Using the Internet Securely answers any questions you might have using the Internet and being secure while you do it, including defining every relevant term: "This document gives home users an overview of the security risks and countermeasures associated with Internet connectivity, especially in the context of "always-on" or broadband access services (such as cable modems and DSL). However, much of the content is also relevant to traditional dial-up users (users who connect to the Internet using a modem)."

And Practically Networked Securing Your LAN page tells you what to do secure your LAN. Or your personal computer, if you don't have a LAN.

How to set up your Home Network with Macs:, At This Particular Macintosh's How To page. And,'s Mac networking pages, which are exceedingly complete, but a bit out of date. Their page on network security:

Turn off file sharing

The first thing to do to protect your always-on-the-Internet personal computer from attack from the outside is turn sharing off on all your disk drives and printers. And you must do it right now. (Unless you have a LAN in your house, of course; in that case, you should put a password on all your drives.) This is particularly important if you have a cable modem, because your computer is on a LAN with your neighbors.

To turn off file and printer sharing in Windows: Double-click the My Computer icon on your desktop. Then right-click on the name of a drive, select Properties, click the Sharing tab, then click the Not Shared radio button. Repeat for each drive. Then double-click the Printers folder and repeat the same process for each printer. If you don't have a Sharing tab, then you're set; your operating system was installed without network sharing options.

To turn off file sharing in Macs: Open the Sharing Setup/Sharing (in Mac OS X) control panel. In the File Sharing/Personal File Sharing (Mac OS X) section, you should see the message "File sharing is off" with a Start button beside it or below it (Mac OS X). If you see a Stop button instead, click it. For Mac OS Classic, a dialog box will open asking "How many minutes until file sharing is disabled?" Select 0 and click OK.

Personal firewall

If you have an always-on Internet connection, via a cable modem or DSL or IDSN line, you must also install a personal firewall (a network protection tool that guards against and reports intrusions on your computer from the outside), and you must keep it running at all times.

To get an idea of what the firewall will do for you, run Symantec's Internet Security Check (Click Continue to Symantec Security Scan​) before and after you install a firewall. Running it might be just the thing you need to convince you to run one. This check requires Internet Explorer 5.0, Netscape 4.5, or Safari 1.0 on a Mac. This service checks the security of your computer's connection to the Internet by sending it various connection requests.

The following two sections list a few specific firewalls for Windows and Macs. For more general (and specific, for that matter), information, see the following firewall Web pages:

For a long list of articles of all flavors about firewalls (including review articles, how-to's, and tutorials), see the open directory project's Top: Computers: Security: Firewalls: FAQs, Help, and Tutorials:

For a comparison, a review, and links to other reviews, see Firewall Guide.Com's Firewall Guide Software Reviews.

C|Net's Why you really, really need a firewall--or two (in case I haven't convinced you), which includes rankings.

For a review of commercial firewalls, see's Top Personal Firewalls - Network Firewall Software.

If you're using ZoneAlarm, check out Robert Graham's FAQ: Firewall Forensics (What am I seeing?) for help interpreting your firewall logs. 

LAN and hardware firewalls

If you have a home LAN and use NAT (Network Address Translation) hardware/software, you can run a firewall on/with the NAT that will protect all of your other machines. For more information including links to lists of available broadband cable/DSL routers, see Home LANs and Sharing Your Internet Connection.

Or you can get a "firewall appliance" -- hardware firewall. Turnkey Network Appliances has a short definition:

For more information:

  • CERT/CC Vulnerabilities, Incidents, and Fixes
    Want to know what's going on in computer security? CERT (Computer Emergency Response Team) is the place to go in the US. CERT was formed by the US Department of Defense in 1988, "to address computer security concerns of research users of the Internet". The CERT Coordination Center (CERT/CC) is in the Software Engineering Institute (SEI), Carnegie Mellon University, Pittsburgh, PA.
  • See also CERT/CC's Home Network Security
    This document answers any questions you might have using the Internet and being secure while you do it, including defining every relevant term.

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Last updated: 

September 03, 2013

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