I've got a very frustrating situation and I hope there will be someone who will be able to figure this out. My Oceanic modem is working fine. My wireless router is working fine. I can surf the web using my wireless router with my iPad. With my iMac, I can connect to the web using FileZilla (to transfer files) and I can add files to my Dropbox account and I can update my Kaspersky Internet Security app BUT I can't get to the web using Firefox or Safari or iTunes! Those apps will launch but will fail to load. When I start up my iMac, I don't get the usual request to allow certain apps to access the web. Clearly, it seems to me anyway, that the problem is somewhere in my iMac. When I go to Preferences > Network and click diagnostics, it says my Ethernet AND wireless connections are working properly. I'm at a loss as to what is preventing my web browsers and iTunes from accessing the web. Everything was working fine until about a week ago and I don't recall installing any new apps. Any suggestions would be very much appreciated. Thank you.