Firewalls foil unauthorized use attempts

There still is a lot of confusion about all the threats lurking in cyberspace just waiting to pounce on our computers. Among these threats are viruses, spyware and people that want to access our computers for their own purposes.

I would like to concentrate on stopping someone from the outside from accessing our computers while we are attached to the Internet. They may want to access files on our machine or, more likely, use our machine to send out spam emails or other data that can’t be traced back to them. Since we don’t want some unauthorized person to use our computers, we foil these attempts by installing a “firewall.” We will leave the discussion of viruses and spyware for another time.

Those of us that use “broadband” connections to the Internet that are “always on” are more concerned with unauthorized access than those who use dialup services that are only occasionally on.

In its simplest form, a firewall is either software or hardware that only allows entry to our computers that we request. If we don’t ask for it, it doesn’t get in.

Technically, when we request to visit, say,, our computer sends out this request to Internet computers “in the sky.” Along with this request, our computer also sends the return address of our computer, our IP (Internet Protocol) address, so that the CNN computer knows where to send back the page we requested. Therefore, our firewall keeps track of our request to CNN and only will allow CNN return access to our computer. Someone in Asia or Europe who is randomly seeking computer IP addresses can’t get to us because our firewall won’t recognize this outside request and will block it.

Firewalls take a number of forms. Microsoft included a software firewall in its Windows XP operating system. Unfortunately its default was OFF and we had to search for it to turn it ON. (Control Panel – Windows Firewall in Windows XP) With the release of Service Pack Two, Microsoft turned the firewall ON and we had to search to turn if OFF.

Since the fear of threats has become popular, many companies have tried to sell us firewalls along with their virus protection programs. McAfee and others have included firewalls in their security suites and independent companies like Zone Alarm have long established firewall software. Those of us with home networks usually have built in hardware firewalls in our routers. Fortunately, it is possible to have more than one firewall activated at a time on our computers. I use the Microsoft firewall along with the one in my network router.

Home firewalls are rather uncomplicated. In commercial settings, firewalls can become very complex, expensive and be used to restrict certain computers from accessing some Internet sites. For instance, the firewall could be set to restrict employees from accessing eBay, Amazon or pornographic sites.

We all should have at least one firewall activated on our home machines regardless of whether we are connected “always on” or dialup. The chance of someone trying to access our particular machine probably is remote, but why not be safe. Incidentally, if our machine is turned OFF, it cannot be accessed from the outside.

If you would like to hear more about firewalls, or other computer topics, visit “Coffee and Computers” at the Tustin Area Senior Center, 200 S. ‘C’ Street, any Friday morning starting at 9 a.m. Bring your questions or just come in and visit. And visit my blog at

In the mean time, keep the neurons happy, synapses snapping and enjoy computing.


Dr. Art Holub is a long time resident of Tustin and teaches computer and Internet courses at the Tustin Area Senior Center and the Tustin Adult School. Visit his web site at: This column is written to address the computer adventures and concerns of older adults. If you have comments, questions or suggestions for future columns, Email HIM at:

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