来源：本文转自“运维研习社” The Netfilter framework was created by Rusty Russell in 1998. It is a subsystem of the Linux kernel, merged into the Linux kernel in March 2000. Netfilter adopts a modular design, providing a well-structured underlying framework for extending various network services. You can register callbacks at various points in the packet traversal process within … Read more
iptables is a classic firewall tool developed for the Linux system based on the netfilter kernel framework, focusing on IPv4 packet filtering and NAT rule configuration. As a built-in component of the Linux kernel, it features efficiency and flexibility, supporting core capabilities such as state detection and fine-grained traffic control. It is the most commonly … Read more
Hello everyone, I am Deng Ju~ iptables is a powerful firewall tool in the Linux system, used to manage firewall rules and network traffic. It allows administrators to configure rules to filter, transform, or forward packets, making it a core component of Linux network and security configuration. With iptables, users can set security policies to … Read more
Fundamentals of Linux iptables: A Guide for Kubernetes Engineers Introduction Before understanding how kube-proxy implements load balancing, we must grasp the underlying Linux networking primitives it relies on. iptables, the built-in firewall system in Linux, is the foundation of Kubernetes’ default proxy mode. Although iptables was originally designed as a security tool, its packet manipulation … Read more
106. Question: To temporarily save iptables rules, the command used is iptables-save > ____. Option 1: rules.txt Option 2: config.rules Option 3: iptables.conf Option 4: saved-rules Correct Answer: 1 Explanation: To temporarily save iptables rules, the command iptables-save > rules.txt is used. This command saves the current firewall rules to a file named “rules.txt” for … Read more
In Linux systems, such as Ubuntu, how can we achieve data forwarding for multiple network connections and port forwarding? The following will explain these two scenarios separately:1. Dual Network Card NAT Networking In Linux, there are two WiFi modules (one for 2.4GHz and the other for dual-band 2.4GHz+5GHz). The router operates on 2.4GHz, while other … Read more
The Role of iptables and the Difference from firewalld 1. What is iptables? What is it used for? iptables is a classic firewall tool on Linux systems, operating at the network layer, with main functions including: Packet Filtering Allowing or blocking specific network traffic based on rules (such as IP addresses, ports, protocols, etc.) Traffic … Read more
Click the blue “Best Programmer” to follow me! Add a “Star“, every day at 18:03 to learn technology together! Complete Guide to Configuring iptables and firewalld Firewalls 1. Basic Concepts of Firewalls 1.1 What is a Firewall A firewall is a network security device that monitors and controls incoming and outgoing network traffic based on … Read more
What is Firewalld? It is a front-end management tool for the Linux kernel’s Netfilter/iptables system. It provides a more user-friendly interface for managing firewall rules, simplifying the complexity of directly using iptables. Firewalld supports dynamic updates, allowing modifications to rules without restarting the service, and introduces the concepts of “zones” and “services” for quickly switching … Read more
Dear friends, you must be very curious about what configuration allows the Linux system to dynamically open and close specific ports. I was also quite surprised when I saw this configuration online. Can the system really dynamically switch specific ports?The answer is yes, and this technology is known as port knocking. This is a method … Read more