Steps for setting up firewall whitelist of RHEL 6 and CentOS 7 under Linux

Go to the Linux command line and edit the firewall rules configuration file iptables
vi /etc/sysconfig/iptables

Here is an example of a whitelist setting:

# 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

The part where the whitelist is set is:

-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

Use the whitelist rule to specify using the j parameter:

-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j whitelist