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Editor to share with you what is the use of the pfctl command in Linux, I believe most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to know it!

Linux common command pfctl command is the configuration command of PF firewall. PF firewall (full name: Packet Filter) is a software system for TCP/ip traffic filtering and network address translation on UNIX LIKE system.

Configuration commands for pfctlPF Firewall

It is added that PF also provides shaping and control of TCP/IP traffic, as well as bandwidth control and packet priority set control. PF was originally developed by Daniel Hartmeier, and now Daniel and other members of the openBSD team are responsible for development and maintenance.

PF firewall has many functions, this site only enumerates some basic configurations.

Activate the line to activate pf and have it invoke the configuration file at startup, edit the / etc/rc.conf file, and modify the line that configures pf:

Pf=yes restarts the operating system for the configuration to take effect.

You can also start and stop pf through the pfctl program:

Pfctl-e pfctl-d Note that this is just starting and shutting down PF. It does not actually load the rule set, which is either loaded at system startup but separately loaded with the command after PF startup.

The configuration system boots to PF to load configuration rules from the / etc/pf.conf file when the rc script file runs PF. Note that when the / etc/pf.conf file is the default configuration file, when the system calls the rc script file, it is simply loaded and interpreted and inserted into the pf by pfctl as a text file. For some applications, other rule sets can be loaded by other files after the system boots. For some very well-designed unix programs, PF provides enough flexibility.

The pf.conf file has seven parts:

Macros: user-defined variables, including IP address, interface name, etc.

Table: a structure used to hold a list of IP addresses.

Options: variables that control how PF works.

Shaping: reprocessing packets, normalizing and defragmenting.

Queuing: provides bandwidth control and packet priority control.

Translation: controls network address translation and packet redirection.

Filtering rules: allow selective filtering and blocking of packets as they pass through the interface.

Apart from macros and tables, other segments should also appear in the configuration file in this order, although not all segments are necessary for some specific applications.

Blank lines are ignored and lines that begin with # are considered comments.

After the control boot, PF can be operated through the pfctl program. Here are some examples:

Pfctl-f / etc/pf.conf # load pf.conf file pfctl-nf / etc/pf.conf # parsing file But do not load pfctl-Nf / etc/pf.conf # load only NAT rules in the file pfctl-Rf / etc/pf.conf # load only filter rules in the file pfctl-sn # display current NAT rules pfctl-sr # display current filter rules pfctl-ss # display current state table pfctl-si # display filter status and count pfctl-sa # display any complete list of commands that can be displayed, see pfctl's man man page.

The above is all the content of the article "what is the use of pfctl commands in Linux". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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