Example of Linux opening port 80 in a firewall

I've been learning Linux lately. Build a LNMP environment. Everything is fine during the test. And then reboot Linux. Access to the Web site cannot be opened again. The final reason is that there are no rules to add port 80 to the firewall. The specific methods are as follows:

It is necessary to configure the Iptables firewall under CentOS. Let's learn how to configure! , the other version:

1. Open the Iptables profile:

The code is as follows	Copy Code
Vi/etc/sysconfig/iptables

Through/etc/init.d/iptables status

The command query has open port 80 if there are no two ways to handle it:

1. Modify the Vi/etc/sysconfig/iptables command to add the firewall to open 80 ports

The code is as follows	Copy Code
-A rh-firewall-1-input-m state--state new-m tcp-p TCP--dport 80-j ACCEPT

2. Turn off/Turn on/reboot the firewall

The code is as follows	Copy Code
/etc/init.d/iptables stop #start Open #restart reboot

After you have added the firewall rules as follows:

The code is as follows

Copy Code

# Firewall configuration written by System-config-firewall # Manual Customization of this file is 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

Add that some friends like to do it

The code is as follows	Copy Code
Vi/etc/sysconfig/iptables -A input-m state–state new-m tcp-p tcp–dport 80-j (allow 80 ports through the firewall) -A input-m state–state new-m tcp-p tcp–dport 3306-j (Allow 3306 ports through the firewall)

In this way, you can find that when you restart the firewall, you return both lines of error.

[Root@localhost ~]#/etc/init.d/iptables Restart
Iptables: Clear Firewall rules: [OK]
Iptables: Set the chain as policy accept:filter [OK]
Iptables: Uninstalling module: [OK]
Iptables: Applying firewall rules: bad argument ' –-state '
Error occurred at Line:11
Try ' iptables-restore-h ' or ' Iptables-restore--help ' for the more information.
Failed

Finding this method does not make sense, try another way to add a port by command.

The code is as follows	Copy Code
[Root@centos httpd]#/sbin/iptables-i input-p tcp--dport 80-j ACCEPT [Root@centos httpd]#/etc/rc.d/init.d/iptables Save [Root@centos httpd]#/etc/init.d/iptables Restart

That's it, look at the effect.

code is as follows	copy code
[Root@centos httpd]#/etc/init.d/iptables status