Software Firewalls May Interfere with New Programs

I received a call from a person to whom I had recommended the Mozilla Firefox web browser. She was having problems with Firefox after its most recent update. She could not connect to any web site using Firefox.

After a little debugging over the phone, where I found out the I.E. worked, but Firefox didn't, I thought of a firewall. Sure enough, she was running a software firewall, and it was blocking Firefox from accessing the Internet.

By default, a firewall program will block any program from accessing the Internet. Sometimes the firewall program comes pre-configured to know about Internet Explorer and Outlook Express. A different firewall program might require that you specifically grant even those two common programs the ability to access the Internet.

When a firewall blocks a program for the first time, it will pop up an information box to warn you that the program is trying to access the Internet. This warning message will allow you to OK the access to the Internet and to tell the firewall to remember the answer, if you want it to remember. There is usually another little innocuous checkbox that says something like "don't ask me again."

This little checkbox can get you in trouble. The "don't ask me again" does not mean with regard to that particular program accessing the Internet. It means "don't ask me again" if any new or different program tries to access the Internet -- just do not allow it the access!

Any program can claim to be any other program by being given the same name, so any self-respecting firewall program will check to make sure that a program (say Firefox.exe) that's trying to get to the Internet today is the same as the one that was allowed access in the past.

If you install a new version or update of a program, the program is no longer the same -- so the application gets blocked and you get a popup window to ask you whether to allow it or not.

But, if you checked that little checkbox, and then install a new or updated program, the new/updated program will not be able to talk to the Internet and you will not know why!

If it happens to you, think of your software firewall, and go check its program settings. ZoneAlarm, Norton Internet Security, Sunbelt Kerio Personal Firewall, and McAfee firewall are easy to change, and I'm sure the others are also.