Last night, when I selected Advanced DNS in my DIR-655, my Brother wireless printer wouldn't connect through the router to my computer.  The same occured when I enter the Advanced DNS addresses into my PPPoE manually without selecting Advanced DNS.  The same also occured when I entered the Open DNS addresses: 208.67.222.222 and 208.67.220.220.  Very interestingly, Google DNS and my AT&T DNS addresses work just fine, i.e., the wireless printer connects to my computer.  
If you are able to explain this to me, please so do it.
Regards, 
Mark.