Yosemite cannot connect with Google, but with Bing I updated my MacBook 13″ mid-2012 from Mavericks to Yosemite and everything was perfect, until I recognized that I couldn't check my YouTube feed. 

I tried again and again, but it didn't work. 

I tried it with other DNS Servers like Norton Security Free-DNS or the Normal Google DNS, but nothing happened. 

In the end, I tried to use the Google IP in my Browser, but that only worked always for one link.

Running the Ping - Google.com results in 


  cannot resolve google.com: unknown host
Assuming you've done this already but just to confirm. This will set you up to use Google's DNS service.


Open the Network pane in System Preferences.
Select the Network connection that is actually in use as indicated by the green dot.
Click Advanced...
Select the DNS tab.
Enter the values from the below screenshot. Take note of anything that is already there under "DNS Servers:" and remove it.
Click on OK to dismiss the Advanced panel and then Apply.


Then try pinging google.com again.