First, check which ports netstat-anp has opened. Second, close the port number: iptables-a input-ptcp-drop port number -jdropptitables-aoutput-ptcp-dport port number-jdrop. Third, open the port number: iptables-a input-ptcp-dport port number -jACCEPT. Four, the following is the use of linux open port command. NC-LP23 (telnet) netstat-an | grep23 (check whether to open port 23) V. linux open port command Each open port needs a corresponding listener to suit the learning path of entry. Please read "This is how Linux should learn".

How to use linux as a router and firewall?

Just install a ready-made soft routing system, most of which are based on linux.

How to disable linux firewall?

The steps to turn off the firewall in LINUX system are as follows:

1. First, open the SSH software, and press Enter to prompt you to log in, and enter the IP and user name to log in.

2. Execute the command: /etc/init.d/iptablesstatus, and you will get a series of messages indicating that the firewall has been opened.

3. Execute the command: /etc/init.d/iptablesstop to stop the service.

4. Execute the command: chkconfig-levels 35 iptables off, close the firewall service and start it. This solves the problem of closing the firewall in LINUX system.

Linux firewall view the current default zone?

Linux can select a firewall through the security settings option to view the current default zone.

Does Linux kernel provide a firewall?

provide

SElinux is a security mechanism based on kernel development, called kernel-level enhanced firewall, which effectively improves the security of the system.

SElinux has two functions: 1. Label the service; 2. Restrict the function above the function

Use the getenforce command in linux system to check the status of selinux:

Disabled is closed, and there are no restrictions on services and functions.

Enforcement is mandatory, which limits services and functions.