Please refer the following steps:
1. Login to your server as root.
2. Edit csf configuration file using the following command:
vi /etc/csf/csf.conf
3. Search the line :
# Allow incoming TCP ports
TCP_IN = “20,21,22,25,26,53,80,110,143,443,465,587,993,995, 2077,2078,2082,2083,2086,2087,2095,2096,28900,2896 0,28970,28860,49030,3333″
4. Add the port no 3306 for mysql in this line.
# Allow incoming TCP ports
TCP_IN = “20,21,22,25,26,53,80,110,143,443,465,587,993,995, 2077,2078,2082,2083,2086,2087,2095,2096,28900,2896 0,28970,28860,49030,3333,3306″
5. Save the changes using by pressing: wq!
6. Refresh the firewall using the following command:
csf –r
7.Last but not the least, you also need to add the same port in TCP OUT just below TCP_IN