Pinging works, but Internet Explorer not showing web pages

Earlier this month, I ran into a very frustrating problem on a clients’ XP computer system. All of a sudden, whenever they would try to open up a web page in Internet Explorer, the result would be “The page cannot be displayed”.

But that was not the frustrating part! This computer was working fine a few days earlier, so something had changed so that now Internet Explorer could not display web pages. The first thing we did was try to ping the websites from the command prompt, thinking that the problem was with the network card, the LAN, or something of that sort.

Pinging the websites actually worked! So now it was really weird. We could ping the websites from the command line, but could not open the page in Internet Explorer. So logically, we jumped to the conclusion that it must have something to do with the proxy settings in Internet Explorer, because DNS is obviously working correctly.

Wrong again! The proxy settings were empty. So if the problem was not related to proxy settings and the TCP/IP protocol was working fine, then what could be the problem? Well, we decided to install another browser and then open a few web pages.

It worked! So Firefox and Google Chrome could load the web sites fine, but not Internet Explorer. We thought about some crazy ideas along the way like the following:

Uninstalling and reinstalling IE
Running the Winsock fix utility
Disabling all add-ons in IE
Running SFC /SCANNOW

However, none of this made sense and we didn’t want to waste a ton of time. So after a while of brainstorming, someone came up with the brilliant idea to see what new software was installed on the computer in the last few days.

Finally, we saw that the user had installed a anti-virus program that had a built-in firewall! The firewall was set to block Internet Explorer from accessing the Internet and therefore was the culprit!

Overall, it was a very good learning experience and I thought I would share it with everyone since it can be super frustrating if you don’t think about third party applications that can cause problems like this. Enjoy!