iptablesによるアクセス制御

 iptables -F
 iptables -X
 
 iptables -P INPUT   DROP
 iptables -P OUTPUT  ACCEPT
 iptables -P FORWARD ACCEPT
 
 iptables -A INPUT -i lo -j ACCEPT
 iptables -A INPUT -p ICMP -j ACCEPT
 iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
 
 iptables -A INPUT -p tcp --dport 22 -j ACCEPT
 iptables -A INPUT -p tcp --dport 1194 -s 123.123.0.0/24 -j ACCEPT
 
 iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o eth0 -j MASQUERADE
 
 iptables -A INPUT -j LOG --log-prefix "IPTABLES_INPUT_LOG: " --log-level=info

 /etc/rc.d/init.d/iptables save
 /etc/rc.d/init.d/iptables restart

 cat /etc/sysconfig/iptables
 /etc/rc.d/init.d/iptables status