Detailed explanation of centos6 and centos7 firewall closure

CentOS 6.5 check the status of the firewall:

[zh@localhost ~]$service iptable status 

Display results:

[zh@localhost ~]$service iptable status

Redirecting to /bin/systemctl status iptable.service

iptable.service

  Loaded: not-found (Reason: No such file or directory)

  Active: inactive (dead)  -- Means the firewall is down  

CentOS 6.5 close the firewall

[root@localhost ~]#servcie iptables stop           -- Temporarily shut down the firewall 

[root@localhost ~]#chkconfig iptables off          -- Permanently shut down firewall  

CentOS 7.2 close the firewall

CentOS 7.0 USES firewall as a firewall by default, but this is changed to iptables firewall step.

firewall-cmd --state # view the default firewall status (notrunning displayed when turned off, running displayed when turned on)

[root@localhost ~]#firewall-cmd --state

not running 

Check the status of the firewall:

Starting with centos7, systemctl is used to manage services and programs, including service and chkconfig.

[root@localhost ~]#systemctl list-unit-files|grep firewalld.service      -- The firewall is off 

firewalld.service              disabled 

or

[root@localhost ~]#systemctl status firewalld.service

firewalld.service - firewalld - dynamic firewall daemon

  Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)

  Active: inactive (dead) 

Close the firewall:

systemctl stop firewalld.service # stop firewall
systemctl disable firewalld.service # prevents firewall from starting

[root@localhost ~]#systemctl stop firewalld.service

[root@localhost ~]#systemctl disable firewalld.service 

 Start the 1 A service: systemctl start firewalld.service

 Shut down 1 A service: systemctl stop firewalld.service

 restart 1 A service: systemctl restart firewalld.service

 According to 1 Service status: systemctl status firewalld.service

 Enable at boot time 1 A service: systemctl enable firewalld.service

 Disable at boot time 1 A service: systemctl disable firewalld.service

 Check whether the service starts up: systemctl is-enabled firewalld.service;echo $?

 View the list of started services: systemctl list-unit-files|grep enabled 

Centos 7 firewall command:

View already open ports:

firewall-cmd --list-ports

Open port

firewall-cmd --zone=public --add-port=80/tcp --permanent

Command meaning:

The scope of the WSD 72en #

Add port: port/communication protocol. Add port: port/communication protocol

The WSD 80en # is permanently active, and will no longer work when restarted without this parameter

Restart the firewall

[zh@localhost ~]$service iptable status

Redirecting to /bin/systemctl status iptable.service

iptable.service

  Loaded: not-found (Reason: No such file or directory)

  Active: inactive (dead)  -- Means the firewall is down  

0

Version CentOS 7 below iptables command

To open port 80,22,8080, type the following command

[zh@localhost ~]$service iptable status

Redirecting to /bin/systemctl status iptable.service

iptable.service

  Loaded: not-found (Reason: No such file or directory)

  Active: inactive (dead)  -- Means the firewall is down  

1

Then save:

[zh@localhost ~]$service iptable status

Redirecting to /bin/systemctl status iptable.service

iptable.service

  Loaded: not-found (Reason: No such file or directory)

  Active: inactive (dead)  -- Means the firewall is down  

2

View the open port:

/etc/init.d/iptables status

Close the firewall

1) it is permanently effective and will not recover after restart

On: chkconfig iptables on

Off: chkconfig iptables off

2) it will take effect immediately and resume after restart

On: service iptables start

Close: service iptables stop

View firewall status: service iptables status

Here's the difference between the default firewalls for CentOS7 and 6

CentOS 7 USES firewall as a firewall by default, and iptables must be reset 1 times

1, directly close the firewall

[zh@localhost ~]$service iptable status

Redirecting to /bin/systemctl status iptable.service

iptable.service

  Loaded: not-found (Reason: No such file or directory)

  Active: inactive (dead)  -- Means the firewall is down  

4

2. Set iptables service

[zh@localhost ~]$service iptable status

Redirecting to /bin/systemctl status iptable.service

iptable.service

  Loaded: not-found (Reason: No such file or directory)

  Active: inactive (dead)  -- Means the firewall is down  

5

If you want to modify the firewall configuration, add firewall port 3306

[zh@localhost ~]$service iptable status

Redirecting to /bin/systemctl status iptable.service

iptable.service

  Loaded: not-found (Reason: No such file or directory)

  Active: inactive (dead)  -- Means the firewall is down  

6

Increase the rules

[zh@localhost ~]$service iptable status

Redirecting to /bin/systemctl status iptable.service

iptable.service

  Loaded: not-found (Reason: No such file or directory)

  Active: inactive (dead)  -- Means the firewall is down  

7

Save after exit

systemctl restart iptables.service # Restart the firewall to enable the configuration 

systemctl enable iptables.service # Set the firewall to boot 

Finally, restart the system to enable the Settings to take effect.

[zh@localhost ~]$service iptable status

Redirecting to /bin/systemctl status iptable.service

iptable.service

  Loaded: not-found (Reason: No such file or directory)

  Active: inactive (dead)  -- Means the firewall is down  

9

Resolved that the host could not access the site in virtual machine CentOS

I installed CentOS6.2 and apache+php+mysql on the virtual machine a while ago, but the machine just couldn't be accessed. I'm not going to do anything.

The details are as follows

1. This function ping is connected to the virtual machine

2. The virtual machine can also connect ping to the machine

3. The virtual machine accesses its web

4. The machine cannot access web of the virtual machine

Later found that the firewall will be 80 port blocked the reason.

To check if port 80 of the server is blocked by the firewall, you can use the command telnet server_ip 80.

The solution is as follows:

/sbin/iptables -I INPUT -p tcp --dport 80 -j ACCEPT 

Then save:

/etc/rc.d/init.d/iptables save 

Restart the firewall

/etc/init.d/iptables restart 

Shut down the CentOS firewall, shut down its services:

See CentOS firewall information: / etc init d/iptables status

Closed CentOS firewall services: / etc init d/iptables stop