Firewalld / iptables

on pew, i removed the iptables and engaged firewalld. These are firewalls that protect the server from unwanted incoming connections.

Check status (you cannot run iptables AND firewalld, but firewalld is recommended now to usurp iptables)
$ systemctl status iptables

Disable and mask iptables
$ sudo systemctl stop iptables
$ sudo systemctl mask iptables

Enable firewalld

$ systemctl enable firewalld

Start firewalld

$ systemctl start firewalld

open port for db

http://www.tecmint.com/configure-firewalld-in-centos-7/2/