My iMac will only connect to certain websites?

Your Mac came with Safari. It's in the Applications folder (safari.app). Please check if Safari can get you to those sites. That should give some clues about what is going on.

I can only think of one thing to check. Go to System Preferences>Network, select your network on the left and click on the Advanced button>Proxies tab. Has anything there got a tick against it. That can sometimes get in the way of getting connected.

See if this procedure helps:

Got to Apple Menu / System Preferences / Network. In Locations, Edit Locations, click the + sign to create a new location. Call it anything you want. You will have to enter a bunch of information about your service provider, etc.

That tick is OK.

Not that you should have to mess around with your settings, but you could try adding OpenDNS numbers to your network settings:

http://use.opendns.com/#mac

Info about OpenDNS:

http://www.labnol.org/internet/tools/opendsn-what-is-opendns-why-required-2/2587 /

It's possible - I've seen it get a bad press on here many times. Ideally it should be uninstalled using the uninstaller from the software developer.

You have to provide the network name, and click on Apply.

BTW, I am assuming this is a wifi connection and Network shows Airport.

You can't delete the question but it'll disappear down the list of posts after a while.

Glad it's sorted.

If you mark one of your posts as Answered, the thread will not be a distraction, and may in fact help others with a similar problem.

I am having the same problem you had. What is we shield and how did you get rid of it?

I meant web shield