IPTables Firewall
IPTables Service
    sudo service iptables status 
      (can use status, start, stop, restart, save) 
Reset IPTables
    sudo iptables --flush 
Only temporarily clears iptables settings Will be restored when service is restarted
    sudo iptables --flush 
    sudo service iptables save 
    or 
    sudo iptables-save 
Makes empty iptables settings permanent
Open a port
    sudo vi /etc/sysconfig/iptables 
Add the following before any REJECT lines
    -A INPUT -p tcp -m tcp --dport <port number> -j ACCEPT 
Save the changes
    sudo service iptables save 
Check for “LISTENING” status
    netstat -a | grep <port number> 
    netstat -a | grep 389 
    netstat -a | grep <group> 
    netstat -a | grep ldap 
Install IPTables-Service
    yum install iptables-services -y 
Stop Firewall
    systemctl stop firewalld 
    systemctl mask firewalld  
mask hides the service unmask makes the service visible
Disable Firewall
    systemctl disable iptables.service 
    systemctl status iptables.service