OS X 10.10.3 connects to wireless router but unable to resolve domain names
Ok, I've figured the problem out in my daughter's macbook. System>Network>Wi-Fi>Advanced DNS tab. I removed the existing DNS servers and used Google's 8.8.8.8, 8.8.4.4. Reopened the browser and it is working now. nslookup and dig also work. Not sure where the DNS servers that I replaced were from or how they got there. I also noticed that in my macbook (one of the ones that were working fine), the DNS server is the wifi router ipaddress. I'm not sure if I should use that or just stick with Googles. Hope this helps someone.