iptables

• How to list iptables rules
• Block an IP using iptables
• Open MySQL Port 3306 in CentOS 7
• Saving iptables firewall rules
• Port forward using iptables
• iptables -F lock me out
• How to redirect traffic to another IP using iptables

To list current rules, run

iptables -S

Or

iptables -L

To list rules in numeric format, run

iptables -nvL

Or

iptables -L -n

To view nat rules

iptables -t nat -L -n --line-number

To see rules with counter, use

iptables -L -n -v

Open port 80

iptables -A INPUT -p tcp --dport 80 -j ACCEPT

To open port 8080 in iptables firewall, run

iptables -A INPUT -m state --state NEW -p tcp --dport 8080 -j ACCEPT

Open Port Range

iptables -A INPUT -p tcp --match multiport --dports 50000:60000 -j ACCEPT

Whitelist an IP

iptables --append INPUT --protocol tcp --source 64.57.102.34 --jump ACCEPT

Forward a Port to Another

All request on port 80 will get forwarded to port 7080

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j DNAT --to-destination :7080

Saving IP tables

Above IP table commands take effect immediatly, but they get lost when you reboot the PC. To make it permanent, run

service save iptables

You can also use

iptables-save > /etc/sysconfig/iptables

Related config are saved in

/etc/sysconfig/iptables
/etc/iptables/iptables.rules

Before Flush

Make sure all Chains are set to ACCEPT, if DROP, run

iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -F