"Fix" The problem that the CentOS firewall does not start

[Author]: Kwu

The CentOS firewall cannot be started, and the online server needs to turn on the Firewall service, which is the most direct and effective way to protect Linux system security.

1. If there is

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

# Firewall configuration written by system-config-firewall# Manual customization of this file is not recommended.*filter:i Nput 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 -j REJEC T--reject-with icmp-host-prohibited-a forward-j reject--reject-with icmp-host-prohibitedcommit

And then start the firewall.

Service Iptables Start

View Firewall Services

Service Iptables Status

3. If you need to open the exception port, add the following configuration:

Vi/etc/sysconfig/iptables

# Firewall configuration written by system-config-firewall# Manual customization of this file is not recommended.*filter:i Nput 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 3306-j accept-a input-j REJECT--reject-with icmp-host-prohibited-a forward-j REJECT --reject-with Icmp-host-prohibitedcommit

As above, 3306 service ports have been added

"Fix" The problem that the CentOS firewall does not start