Can connect to router but not internet My MacBook (El Capitan 10.11.2) one day cannot connect to the internet via wifi. It work solidly beforehand.

My router setting has not changed. Nor have any device white/black-listing.
Other devices can connect to the router and internet fine.


ping 192.168.1.1 works 
nslookup stackexchange.com works 
nslookup stackexchange.com 8.8.8.8 fails 
ping stackexchange.com times out


Interestingly if I connect to the Router's wifi guest, it works fine.
So a desktop that's connecting to the router via ethernet cable experience the same exact problem! Many other devices operated fine. This allow me to pinpoint the router is messed up somehow. 

A power down restart on the router fixed everything.