What firewalls does Linux have?

1) the concept of firewall is mainly used to intercept and filter transmitted data packets in enterprises.

Certain actions can be done when the conditions are met, and traffic is prohibited or running, which can be divided into the following

Two types of firewalls:

 hardware firewall (Cisco, Huawei, Shanshi Netcom)

 software firewall (Iptables, Firewalld)

2) IPtables is a built-in software-level fire protection based on packet filtering in Linux system.

Wall, Iptables mainly works on the second, third and fourth layers of the seventh layer of OSI (data link

Layer, network layer, transport layer)

3) IPtables is made up of tables and rules, and its products are filtering rules, while rules

Is stored in a table, where the table stores the Linux kernel, commonly referred to as a firewall:

Netfilter/Iptables, in fact, Netfilter and Iptables are different.

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4) Netfilter is a Linux kernel module, which belongs to the kernel space level and defaults to the system.

Installation completed, integrated in the Linux kernel module, mainly storing data filter tables

Rules for storing filtering in the table

5) Iptables is the Linux system software, which belongs to the user space level and defaults to system security.

Installed and integrated into the Linux operating system, mainly managing the bottom layer of Netfilter

Module for convenient management of Netfilter underlying data filter tables and rules