Back in October 2012, I started getting the “Firefox can’t find the server at…” message, so I changed my MacBook Pro settings to use OpenDNS, which solved the problem.
Until today, I had forgotten that I changed the DNS setting, until I got that message for the first time using OpenDNS, so, now that I have Google Fiber, I switched back to using the default DNS Setting. To do this, I:
Opened System Preferences | Network. Clicked on Advanced…(In the bottom right hand corner)
Clicked on DNS, and removed the two OpenDNS ip addresses that I had added in October:
Then, OSX automatically reverted back to the single default address.
Shortly after doing this, I got a browser message that the computer was not on the internet, so I went back into System Preferences | Network, and selected my home network.