Telnet command to determine if the port is not through

The above concludes that port 80 does not pass

View Iptables

Vi/etc/sysconfig/iptables #编辑防火墙配置文件
-A input-m state--state new-m tcp-p TCP--dport 80-j ACCEPT (allow 80 ports via firewall)
-A input-m state--state new-m tcp-p TCP--dport 3306-j ACCEPT (Allow 3306 ports via firewall)

Special Note: Many netizens add these two rules to the last line of the firewall configuration, causing the firewall to fail to start

The correct one should be added to the default 22 port under this rule, after adding the firewall rule as follows:

#########################################################
# Firewall configuration written by System-config-firewall
# Manual Customization of this file are not recommended.
*filter
: INPUT ACCEPT [0:0]
: FORWARD ACCEPT [0:0]
: OUTPUT ACCEPT [0:0]
-A input-m state--state established,related-j ACCEPT
-A input-p icmp-j ACCEPT
-A input-i lo-j ACCEPT
-A input-m state--state new-m tcp-p TCP--dport 22-j ACCEPT
-A input-m state--state new-m tcp-p TCP--dport 80-j ACCEPT
-A input-m state--state new-m tcp-p TCP--dport 3306-j ACCEPT
-A input-j REJECT--reject-with icmp-host-prohibited
-A forward-j REJECT--reject-with icmp-host-prohibited
COMMIT
#########################################################

/etc/init.d/iptables Restart #最后重启防火墙使配置生效

Telnet command to determine if the port is not through