I used Ubuntu Mate since 16.04, worked great through 16.10 but I broke it when I tried to upgrade it to 17.04 beta. Never mind, I decided to install Xubuntu 16.10 on other partitions to try something new, which turns out not bad. Upgraded Xubuntu to 17.04, Wifi issues occurred, where Wifi is shown as connected but I cannot browse any site, cannot update/upgrade using "sudo apt update/upgrade ", etc.
I have searched for days and nights and tried the following methods:
(1) adding
[device] wifi.scan-rand-mac-address=no
to “/etc/NetworkManager/NetworkManager.conf”
No improvement.
(2) adding 8.8.8.8 as DNS, most sites work but local sites (*.hk, even www.google.com.hk) may not work.
(3) using 4.11 AMD64 RC7 kernel.
The problem should be related to DNS because it’s fine when I pinged with IP addresses. I thought maybe the update from Xubuntu 16.10 to 17.04 caused the issue, so I fresh install Ubuntu Mate 17.04 (reformatted the original Ubuntu Mate 16.10). The Wifi issue still hit me in the face after this fresh install, driving me crazy. The problem still exist as at today.