:: What is CSF
CSF firewall commonly known as Configserver Security and Firewall has become one of the popular firewall not just because of its easy of use it also provides a cpanel interface and can be easily installed and tuned by any novice users. If you are running cpanel without firewall then CSF firewall is very much recommended, considering the security aspects of your server.
 

:: How to allow outgoing mysql on CSF

add port 3306 on outgoing

 

:: How to allow outgoig mysql only one ip

add line like:

 
:: Restarting csf

 
:: Links
+ Google
+ cPanel