Solve the problem that CentOS firewall cannot be started

CentOS firewall cannot be started, and the firewall service must be enabled for all online servers. this is the most direct and effective method for linux system security protection. 1. if serviceiptablesstartserviceiptablesrestart fails to start/restart the firewall. 2. the best way is to modify the configuration file vi/etc/sysco.

CentOS firewall cannot be started, and the firewall service must be enabled for all online servers. this is the most direct and effective method for linux system security protection.

1. if

Service iptables start

Service iptables restart

When the firewall cannot be started/restarted.

 

2. the best way is to modify the configuration file.

Vi/etc/sysconfig/iptables

 

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1. # Firewall configuration written by system-config-firewall
2. # Manual customization of this file is not recommended.
3. * Filter
4. : Input accept [0: 0]
5. : Forward accept [0: 0]
6. : Output accept [0: 0]
7. -A input-m state -- state ESTABLISHED, RELATED-j ACCEPT
8. -A input-p icmp-j ACCEPT
9. -A input-I lo-j ACCEPT
10. -A input-m state -- state NEW-m tcp-p tcp -- dport 22-j ACCEPT
11. -A input-j REJECT -- reject-with icmp-host-prohibited
12. -A forward-j REJECT -- reject-with icmp-host-prohibited
13. COMMIT

 

 

Then start the firewall.

Service iptables start

View firewall services

Service iptables status

 

3. if you need to enable the exception port, add the following configuration:

Vi/etc/sysconfig/iptables

 

[Plain]View plaincopy

1. # Firewall configuration written by system-config-firewall
2. # Manual customization of this file is not recommended.
3. * Filter
4. : Input accept [0: 0]
5. : Forward accept [0: 0]
6. : Output accept [0: 0]
7. -A input-m state -- state ESTABLISHED, RELATED-j ACCEPT
8. -A input-p icmp-j ACCEPT
9. -A input-I lo-j ACCEPT
10. -A input-m state -- state NEW-m tcp-p tcp -- dport 22-j ACCEPT
11. -A input-m state -- state NEW-m tcp-p tcp -- dport 3306-j ACCEPT
12. -A input-j REJECT -- reject-with icmp-host-prohibited
13. -A forward-j REJECT -- reject-with icmp-host-prohibited
14. COMMIT

 

As shown in the preceding figure, Port 3306 is added.

 

If you need to disable the firewall to start automatically

View status

 

Chkconfig -- list iptables disable automatic chkconfig iptables off

View status

Chkconfig -- list iptables