Configure iptables firewall for CentOS to allow external MySQL access

Abstract: By default, the iptables information filtering system is installed in centos. Currently, you need to configure the system to allow remote access to mysql. Related Knowledge: iptables related 1. iptables service/etc/init. d/iptablesstart | stop | restart |... 2. configuration file location/etc/sysconfig/iptables-config3, policy file Abstract:
　　 CentosBy default IptablesInformation filtering system. MysqlRemote access.
Related knowledge:
　　 Iptables problems
1. iptables service/etc/init. d/iptablesstart | stop | restart |...
2. configuration file location/etc/sysconfig/iptables-config
3. location of the policy file/etc/sysconfig/iptables (the default value does not exist. you can use service ipatablessave to save the current policy)
4. View iptables-L (if you specify to view a rule, for example, iptables-l input is used for INPUT)
5. create a rule iptables... for example: (For more details, see iptables firewall configuration in RHEL5.7)
　

6. save the current rule service iptables save (or/etc/init. d/iptables save or iptables-save>/etc/sysconfig/iptables)
Save is to append the rule to a file, mainly with the iptables-restore command
7. restore policy file service iptables restore
　　
Mysql access configuration:
Iptables-a input-p tcp-m state -- state NEW-m tcp -- dport 3306-j ACCEPT
Service iptables save
Service iptables restart

Related questions:
1. configure/sbin/iptables and check their differences.
/Bin is generally a common executable program, while/sbin is mostly a system management program and a service program.
S should be the word "system ".