1. List all services enabled/disabled on boot (ex chkconfig –list)

systemctl list-unit-files

2. Enable HTTPD + Mysql service on system boot:

systemctl enable httpd
systemctl enable mariadb

3. Reverting to iptables from firewalld

systemctl stop firewalld
systemctl mask firewalld

yum install iptables-services

systemctl enable iptables
systemctl start iptables

# to save iptables rules use
service iptables save