no internet connection on iMac inspite of full wlan connection

Hello,

In a browser's URL bar, put this & hit enter, does that get you to Apple?

17.149.160.49

If so...

For 10.5/10.6/10.7/10.8, System Preferences>Network, unlock the lock if need be, highlight the Interface you use to connect to Internet, click on the advanced button, click on the DNS tab, click on the little plus icon, then add these numbers...

208.67.222.222

208.67.220.220

(There may be better or faster DNS numbers in your area, but these should be a good test).

Click OK.

Wifi problems seem to crop up a lot on here and unfortunately there doesn't seem to be a 'one fix' solution.

However, sometimes any one of the following can help although, unfortunately, not always - in no particular order:

• Check wifi security - if it's WEP change it to WPA or WPA2 (preferably, as it's more secure)
• Change the wifi channel on the router
• Create a new Network Location: http://support.apple.com/kb/HT5289
• Reboot the router

Also take a look at this link and the links within the article for other ideas. They mainly reference Lion, but still seem to be relevant to Mountain Lion:

http://osxdaily.com/2011/11/06/lion-wi-fi-problems-solution-mac/?utm_source=feed burner&utm_medium=feed&utm_campaign=Feed%3A+osxdaily+%28OS+X+Daily%29&utm_conte n t=FaceBook

...and this link:

http://osxdaily.com/2012/11/30/resolving-stubborn-wi-fi-connection-problems-in-m ac-os-x/

It looks like you've tried plenty of troubleshooting steps, so if the Mac is brand new perhaps a phone call to AppleCare would be a good next step. You have 90 days free support (3 years if you bought the extended AppleCare). They may even replace the machine if they can't figure out a way of resolve its wifi issues.

Frustrating that it won't connect. You said that your other devices are connected, but I don't suppose you have MAC address filtering enabled on the router - that would prevent connections if it's not put into 'association' mode.

You can buy the extended AppleCare any time during the first year 😉.

If 'copying' the working settings from one of the other macs, (changing the ip if fixed on those) doesn't do it, you may find help at http://forums.whirlpool.net.au/forum/82?g=295

I have been having this problem with just one of our iMacs in our house. I went through Apple support and navigated through all the twists and turns they suggestedto try to get the problem solved. NOTHING WORKED. THEY DON"T KNOW HOW TO FIX THIS PROBLEM. BUT I DO! Unfortunately it involves buying a $30 wireless ethernet adapter (I got an IOGEAR, and I have no connection to their company. Probably any wireless ethernet adapter will work). I turned off the internal airport wireless device and through the network settings in the system preferences connected to my CISCO LYNKSYS ROUTER (which has been bashed left and right in the forums here). THE PROBLEM IS SOLVED!!!!! NO RESTARTING!!! NO DROPPED CONNECTIONS!!!!

So the problem isn't with the router, its with the airport wireless adapter in the iMac.

A wireless usb adapter works just as well.

Don't waste any more of your time. Just get the adapter, and start enjoying the otherwise great product from Apple.