Iptables entry-level application cases

Linux provides a very good firewall tool netfilter/Iptables. This article briefly introduces the use of netfilter/IptablesImplements firewall setup, Internet Connection Sharing, and other applications to maintain server security vulnerabilities.

Disable Firewall

 
 

  
  
iptables -P INPUT ACCEPT 
 
 

Open Firewall

 
 

  
  
iptables -F INPUT  
  
  
iptables -P INPUT DROP 
 
 

-- Disable port 3306 (Mysql database)

 
 

  
  
iptables -I INPUT -i eth0 -p tcp --dport 3306 -j DROP  
  
  
iptables -I INPUT -i eth0 -p tcp --dport 3306  -j ACCEPT 
 
 

In linux, port 81 is usually disabled.

Enable port 81:

 
 

  
  
iptables -I INPUT -i eth0 -p tcp --dport 81 -j ACCEPT  
  
  
iptables -I OUTPUT -o eth0 -p tcp --sport 81 -j ACCEPT 
 
 

Close port 81:

 
 

  
  
iptables -I INPUT -i eth0 -p tcp --dport 81 -j DROP  
  
  
iptables -I OUTPUT -o eth0 -p tcp --sport 81 -j DROP 
 
 

Then save:

 
 

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

Check whether there are already:

 
 

  
  
[root@vcentos ~]# /etc/init.d/iptables status 
 
 

Save as follows.

Summary:

IptablesThe content of the Getting Started application case has been introduced.IptablesLearning the entry content is helpful to you!