Finally I have it work!
Step 1: change setting info in /etc/mysql/my.cnf
- comment out bind-address = 127.0.0.1 (it's for localhost only)
- add safe-show-database (for security reason)
- change server and client mysql default port 3306 to any other port number (e.g. 12345)
Step 3: open the specific port you just set
Step 4: test & done!