The answer is "Yes", our Windows and Linux server do support MySQL Front through Port 3306.
However external IP has to be set up in CPanel (linux) in order to connect using MySQL Front. The steps outlined as below.
1) Login to CPanel > Remote MySQL
2) Enter your external IP and press Add Host
3) You could obtain your external IP by: http://myip.dk
4) The IP have to be updated if using dynamic IP address once restarted ISP connection.