Basic IP Block
iptables - A INPUT - i eth0 - p tcp - s 1.1.1.1 - j DROP
Allow incoming SSH
iptables - A INPUT - i eth0 - m state -- state NEW , ESTABLISHED - m tcp - p tcp - s 1.1.1.1 -- dport 22 - j ACCEPT
Allow incoming SSH from a Sepcific Network
iptables - A INPUT - i eth0 - m state -- state NEW , ESTABLISHED - m tcp - p tcp - s 1.1.1.1 / 24 -- dport 22 - j ACCEPT
Combine Multiple Ports roles
iptables - A INPUT - i eth0 - m state -- state NEW , ESTABLISHED - m tcp - p tcp - s 1.1.1.1 / 24 -- dport 22 , 80 , 443 - j ACCEPT
Load Balance Incoming Web Traffic
iptables - A PREROUTING - i eth0 - p tcp -- dport 443 - m state -- state NEW - m nth -- counter 0 -- every 3 -- packet 0 - j DNAT -- to - destination 192.168.1.101 : 443
iptables - A PREROUTING - i eth0 - p tcp -- dport 443 - m state -- state NEW - m nth -- counter 0 -- every 3 -- packet 1 - j DNAT -- to - destination 192.168.1.102 : 443
iptables - A PREROUTING - i eth0 - p tcp -- dport 443 - m state -- state NEW - m nth -- counter 0 -- every 3 -- packet 2 - j DNAT -- to - destination 192.168.1.103 : 443
Prevent Dos Attack
iptables - A INPUT - p tcp -- dport 80 - m limit -- limit 25 / minute -- limit - burst 100 - j ACCEPT
Port Forwarding 422-> 22
iptables - t nat - A PREROUTING - p tcp - d 192.168.102.37 -- dport 422 - j DNAT -- to 192.168.102.37 : 22