進入Linux 命令行，編輯防火牆規則配置文件 iptables
vi /etc/sysconfig/iptables
下面是一個白名單設置的例子：
# Firewall configuration written by system-config-securitylevel
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:RH-Firewall-1-INPUT - [0:0]
-N whitelist
-A whitelist -s 10.202.106.1 -j ACCEPT
-A whitelist -s 10.202.106.2 -j ACCEPT
-A whitelist -s 10.202.106.3 -j ACCEPT
-A whitelist -s 10.202.106.4 -j ACCEPT
-A whitelist -s 10.202.106.5 -j ACCEPT
-A whitelist -s 10.202.106.6 -j ACCEPT
-A whitelist -s 10.202.106.7 -j ACCEPT
-A INPUT -j RH-Firewall-1-INPUT
-A FORWARD -j RH-Firewall-1-INPUT
-A RH-Firewall-1-INPUT -i lo -j ACCEPT
-A RH-Firewall-1-INPUT -p icmp --icmp-type any -j ACCEPT
-A RH-Firewall-1-INPUT -p 50 -j ACCEPT
-A RH-Firewall-1-INPUT -p 51 -j ACCEPT
-A RH-Firewall-1-INPUT -p udp --dport 5353 -d 224.0.0.251 -j ACCEPT
-A RH-Firewall-1-INPUT -p udp -m udp --dport 631 -j ACCEPT
-A RH-Firewall-1-INPUT -p tcp -m tcp --dport 631 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 4750 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j whitelist
-A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited
COMMIT
其中設置白名單的部分為：
-N whitelist
-A whitelist -s 10.202.106.1 -j ACCEPT
-A whitelist -s 10.202.106.2 -j ACCEPT
-A whitelist -s 10.202.106.3 -j ACCEPT
-A whitelist -s 10.202.106.4 -j ACCEPT
-A whitelist -s 10.202.106.5 -j ACCEPT
-A whitelist -s 10.202.106.6 -j ACCEPT
-A whitelist -s 10.202.106.7 -j ACCEPT
使用白名單規則使用 j 參數指定：
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j whitelist