Overview
While hosting Kayako Classic on Azure, you might have noticed an option to have port 3306 available Publicly or Privately. You might ask if there's a requirement in the Kayako functionality for this port to be publicly available or not.
Information
Since the server is hosted on Azure infrastructure then the port MySQL uses to communicate with the DB server should remain publicly available.
This is because the MySQL server and the Database are two separate things, and the server needs to be able to communicate with the database for proper help desk functionality.
While changing the default port for MySQL is possible, you would need to make sure it is changed in all the places it is referenced in the server's configuration files as well as for the php.ini file. So, unless there is a strong need to change the default port or to make it private only, it is recommended to leave the default settings.
If you need to make changes, there are two files you need to look at:
PHP -- php.ini
mysqli.default_port = 3306
MySQL -- my.ini
[client]
port = 3306
socket = /tmp/mysql.sock
[wampmysqld64] (if the field is available, if not then disregard)
port = 3306
socket = /tmp/mysql.sock
[mysqld]
default_authentication_plugin=mysql_native_password
port = 3306