/etc/sysconfig/iptables basic template

iptables

*filter

# deny all inbound
:INPUT DROP [0:0]
:FORWARD DROP [0:0]

# accept all outbound
:OUTPUT ACCEPT [0:0]

# accept already connected sessions
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

# accept all loopback
-A INPUT -i lo -j ACCEPT

# accept http port from anywhere
-A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT

# accept ssh port from anywhere
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT

# deny from specific IP address
-A INPUT -m state --state NEW -s 1.2.3.4 -j DROP

COMMIT