This guide explains how to protect a shared development TCP port—used as a sidecar proxy for a Unix Domain Socket—by applying per‑IP rate limiting with iptables' hashlimit module, including full command examples, parameter details, and practical calculations.
This article provides a concise tutorial on using iptables to reset, delete, flush, list, and configure firewall rules on a Linux node, covering port blocking, IP blocking, rule negation, multi‑port matching, stateful filtering, and default policies.
This article explains firewalls by defining their purpose, describing how they monitor and filter network traffic, outlining their architecture—including screening routers and proxy servers—and listing their key security functions such as access control, traffic filtering, logging, and attack detection.
This article explains the security risks of early Internet protocols, the evolution of SSL/TLS and DTLS, fundamental cryptographic concepts such as symmetric and asymmetric encryption, hashing, MACs, digital signatures, AES modes and padding, and how these technologies are applied in TLS handshakes, DTLS, and WebRTC.
This article explains the fundamentals of the HTTP protocol, illustrates how plain‑text communication enables man‑in‑the‑middle attacks, and describes how symmetric and asymmetric encryption, SSL/TLS handshakes, and CA certificate chains are used in HTTPS to secure web traffic.
The article examines why conventional next‑generation firewalls (NGFW) struggle with sophisticated, unknown attacks, and explains how Huawei’s AI firewall leverages cloud‑trained and on‑premise unsupervised learning models, dedicated hardware, and encrypted‑traffic analysis to automatically detect and mitigate advanced threats across the attack chain.
SSL/TLS protects internet traffic by encrypting data, verifying integrity, and authenticating parties, and this article outlines its purpose, historical evolution, core operation using public‑key and symmetric keys, and details each step of the handshake process that establishes a secure session.
The article explains how IPv6 addresses the address shortage, security, and scalability challenges of government external networks, outlines IPv6 advantages such as abundant address space, extensibility, and higher security, and describes the emerging IPv6+ ecosystem with SRv6, network slicing, and AI-driven operations.
This guide explains the architecture of iptables—including tables, chains and rules—covers common targets, shows how to list, flush, persist and modify rules, and provides complete examples for SSH, HTTP, NAT port forwarding and source‑IP restrictions on Linux firewalls.
This article explains how Tigera’s Calico integrates the open‑source WireGuard VPN with Azure Kubernetes Service using Azure CNI, detailing packet flow, encryption benefits, configuration steps, MTU handling, and RPF considerations to achieve secure, high‑performance intra‑cluster communication.
This tutorial walks through building both command‑line and Tkinter‑based Python tools that scan nearby Wi‑Fi networks, read password dictionaries, and perform brute‑force attacks using the pywifi library, while also showing how to package the script as an executable and discussing potential multithreading improvements.
This article explains how HTTPS uses SSL/TLS to encrypt data, authenticate servers, and protect integrity, then examines the handshake process, certificate authority verification, man‑in‑the‑middle attacks, and why HTTPS alone cannot guarantee absolute security.
This article demonstrates how to use Python and the pywifi library to scan nearby Wi‑Fi networks and perform a dictionary‑based brute‑force attack, then improves the tool with a command‑line version, a more flexible script, and two Tkinter graphical interfaces for easier operation.
This article explains the DNS hijacking threat, shares a real incident affecting NetEase Cloud IM, and details a comprehensive high‑availability architecture—including HttpDNS, laddered HTTP requests, caching strategies, and SNI handling—that protects the SDK from DNS attacks and ensures reliable service.
This article investigates whether a company can monitor WeChat conversations by analyzing the web and mobile protocols, detailing how SSL/TLS, MMTLS, private TCP connections, and embedded cryptographic keys affect the visibility of chat messages on corporate networks.
This guide demonstrates how to use Python's Scapy library to extract IP addresses from PCAP files, sniff usernames and passwords from mail traffic, discover live hosts via SYN packets, launch MAC address table flooding attacks, and conduct ARP spoofing for man‑in‑the‑middle attacks, providing complete code examples.
In the post‑pandemic era, remote work and multi‑cloud adoption have exposed the limits of traditional perimeter defenses, prompting a shift toward zero‑trust models where Software‑Defined Perimeter (SDP) plays a pivotal role in safeguarding enterprise networks.
The article provides a comprehensive overview of white‑box switches, covering their rapid evolution over the past three decades, open‑source ecosystems, hardware‑software decoupling, programmable networking, hardware acceleration, security challenges, and emerging trends shaping future network architectures.
This article provides a comprehensive guide to iptables, covering its underlying netfilter architecture, the five built‑in chains and tables, rule syntax, common match and target options, and practical command examples for adding, deleting, querying, and managing firewall rules on Linux systems.
This article presents a curated list of network security utilities—including anti‑malware, scanners, encryption, IDS, port scanners, exploit frameworks, monitoring, proxies, wireless, rootkit detectors, and packet sniffers—each with brief descriptions and download links for aspiring security practitioners.
The 2020 Global Network Trends Report analyzes how large‑scale automation, intent‑based networking, AI‑driven assurance, multi‑cloud connectivity, wireless evolution, and shifting security roles are reshaping enterprise networks, highlighting adoption statistics, technical challenges, and strategic recommendations for IT leaders.
The paper introduces a community‑encoding, GraphSAGE‑based detection framework that embeds whole user‑account, IP, device, and phone‑number graphs—both homogeneous and heterogeneous—to identify previously unseen black‑gray industry attacks, achieving about 95% IP‑risk accuracy via an asynchronous near‑real‑time system, though computational and automation challenges persist.
This article provides concise explanations of core networking concepts, covering everything from basic link definitions, OSI model layers, and backbone networks to LANs, nodes, routers, point‑to‑point links, FTP, subnet masks, UTP cable limits, data encapsulation, network topologies, VPN, NAT, TCP/IP layers, routing protocols, security measures, and many other fundamental topics essential for understanding computer networks.
This comprehensive tutorial explains what tcpdump is, how it differs from Wireshark, walks through its core parameters, output format, common and advanced filtering rules, optional flags, and provides dozens of practical command‑line examples for precise packet capture on Unix systems.
This article explains how mid‑size enterprises can inventory their network assets, understand complex zone structures, and apply full‑traffic network analysis and tracing techniques—such as SPAN, tunneling, and real‑time monitoring—to improve the effectiveness of security drills.
This article examines whether a company can monitor WeChat conversations on its network by dissecting the web and mobile versions' protocols, demonstrating how tools like Fiddler and Wireshark can decrypt web chats while mobile traffic remains secure through private protocols and embedded server keys.
This guide reviews the most frequent TCP/IP attacks—including IP spoofing, SYN flooding, UDP flooding, TCP reset hijacking, man‑in‑the‑middle, and DDoS—explains their underlying protocols, demonstrates practical exploitation with Python/Scapy and Netcat, and outlines mitigation techniques and cryptographic fundamentals.
The article commemorates Dan Kaminsky, the renowned information‑security researcher who uncovered the critical DNS vulnerability in 2008, outlines his career, explains the impact of his discovery and coordinated patch, and dispels rumors surrounding his death.
Learn comprehensive MySQL security strategies covering storage RAID configurations, network whitelisting, OS hardening, account management, privilege restrictions, audit logging, regular backups, data encryption, and disaster recovery to protect enterprise data against breaches and ensure stable, high‑performance operations.
This comprehensive guide explains remote‑control trojans—covering their basic concepts, classifications, infection methods, communication techniques, typical functionalities, their role in APT attacks, and practical detection strategies—providing security professionals with essential knowledge to defend against these sophisticated threats.
This article explains how increasing network attacks exploit vulnerabilities across TCP/IP layers, detailing ARP spoofing, DoS techniques, and DNS hijacking, while outlining detection methods and defensive measures to protect information security.
This article introduces the Netwox network tool suite, explains its installation and extensive command modules, demonstrates how to perform ARP cache poisoning and TCP SYN flood attacks with concrete code examples, and highlights the importance of responsible usage in network security testing.
This article explains the inherent insecurity of plain HTTP, illustrates man‑in‑the‑middle attacks, shows why simple symmetric encryption is insufficient, and details how HTTPS (SSL/TLS) with asymmetric key exchange and CA verification protects data transmission.
This article explains the Zero Trust security model, its advantages over traditional perimeter defenses, core technologies such as SDP, IAM, and micro‑segmentation, implementation principles, essential components, real‑world deployment scenarios, future trends, and Tencent's practical contributions to the industry.
This article explains the fundamentals of the HTTP protocol, illustrates its susceptibility to man‑in‑the‑middle attacks, discusses mitigation techniques using symmetric and asymmetric encryption, and describes how HTTPS with TLS and a CA certification system protects data integrity and confidentiality.
This article presents a comprehensive study on using graph representation learning, particularly GraphSAGE and its optimizations, to identify and mitigate black‑market accounts in virtual networks, covering background, algorithm design, handling isolated nodes and heterogeneity, and evaluation results.
This guide explains how the scp command works as a secure copy tool built on SSH, covering its basic syntax, three main copy scenarios, essential options for encryption, compression, bandwidth control, and practical examples for transferring files and directories between local and remote hosts.
This article explains why plain HTTP is insecure, illustrates man‑in‑the‑middle attacks, discusses symmetric and asymmetric encryption attempts, and details how HTTPS (SSL/TLS) with CA certificate verification protects data integrity and confidentiality.
This article explains the insecurity of plain HTTP, demonstrates how man‑in‑the‑middle attacks can intercept and modify traffic, and details how HTTPS using SSL/TLS, asymmetric key exchange, and CA‑based certificate verification secures web communications.
This article explains how HTTPS secures web communication by combining asymmetric certificate verification with symmetric data encryption, details the role of Certificate Authorities, illustrates the handshake process, and clarifies common misconceptions about its safety and vulnerability to packet capture.
This guide introduces SSH, explains its encryption-based login mechanism, demonstrates common commands for remote access, local and remote port forwarding, dynamic tunneling, and highlights security risks such as man‑in‑the‑middle attacks, providing practical examples for Linux environments.
This article explains a passive method that captures SYN packet IP headers in user space, extracts OS‑specific features to build a fingerprint database, and uses the results to improve human‑machine detection while discussing implementation details on Linux kernels and typical network architectures.
This guide explains what SSH is, its login principles, basic commands, remote login examples, and detailed usage of local, remote, and dynamic port forwarding, as well as common security concerns and practical tips for Linux environments.
This article explains why plain HTTP is insecure, outlines the four fundamental principles of secure communication, and details how HTTPS uses symmetric encryption, asymmetric encryption, digital certificates, and digital signatures to establish confidentiality, integrity, authentication, and non-repudiation for web traffic.
This article introduces SSH, explains its encryption-based login mechanism, demonstrates basic command syntax, shows practical examples of remote login, local/remote/dynamic port forwarding, remote command execution, and discusses common security concerns such as man‑in‑the‑middle attacks.
This article presents the complete PPT from Zhu Yanyong’s CSDN live session, detailing offensive and defensive practices for ensuring network security during large‑scale events, covering threat modeling, DDoS mitigation, WAF deployment, incident response, and post‑event analysis.
This article provides a comprehensive guide to using iptables for port forwarding, explains the four tables and five chains, details common command syntax, match criteria, actions, additional modules, and includes practical examples for NAT configuration and protecting against small‑scale attacks.
This guide explains how to configure a router to block selected LAN hosts from accessing the Internet by applying source‑MAC‑address based ACLs while still permitting those hosts to reach the gateway, using VLAN, traffic classifiers, and traffic policies.
An imaginative tale reveals how two covert agents exploit the Linux kernel’s DelayedACKLost counter via /proc/net/netstat, using it to infer TCP sequence numbers and perform a side‑channel hijack, while illustrating the underlying delayed ACK mechanism, related kernel functions, and the security implications of this hidden metric.
The article explains DDoS attack fundamentals, illustrates escalating real‑world incidents and their mitigation, and compares Tencent Cloud’s free, high‑defense package, and high‑defense IP solutions, guiding readers on selecting appropriate protection based on attack history, bandwidth needs, and budget constraints.
This tutorial walks through creating a multi‑node KIND Kubernetes cluster, disabling the default CNI, installing Cilium 1.8.2 via Helm with Hubble enabled, demonstrating eBPF‑based network security and observability, deploying a test application, and verifying CiliumNetworkPolicy effects.
Learn to uncover concealed Wi‑Fi networks by capturing router signals with a wireless adapter, using Ubuntu’s airodump-ng and Python’s Scapy library to monitor packets, identify hidden SSIDs, and display them when a client connects, complete with step‑by‑step setup and screenshots.
This guide explains what SSH is, its login mechanism, basic command syntax, and demonstrates remote login, local and remote port forwarding, dynamic forwarding, and common SSH operations with practical examples and troubleshooting tips for Linux environments.
This article presents a series of algorithmic innovations—including efficient NFA construction, reduced epsilon‑transitions, prefix/suffix optimizations, fast NFA‑to‑DFA conversion, space‑compressed automata, hybrid finite automata, and large‑scale regex matching techniques—designed to improve regular‑expression matching speed and memory usage in deep packet inspection systems.
The article explains how the DNS system works, why there are only 13 logical root servers, how anycast and global mirrors keep the system resilient, and evaluates the realistic risk of a nation‑state like the United States tampering with root zone data, especially for Chinese .cn domains.
This article explains how DNS works, why there are only 13 logical root servers, how root mirrors and anycast keep the system resilient, the historical control of root zones, and why the United States cannot easily block Chinese domains despite its dominance in root server ownership.
The article explains how DNS works, why there are only 13 logical root servers, how anycast and mirror servers provide resilience, recounts historical cases of domain shutdowns, examines US control over root zones, and discusses mitigation strategies for protecting national domains.
This article explains the differences between Next‑Generation Firewalls and Web Application Firewalls, highlighting the additional protection that a WAF—especially F5’s solution—provides for complex web applications and why combining both technologies offers comprehensive security.
This article explains why HTTP is insecure, demonstrates a plain‑text attack using Wireshark, and then details the encryption types, certificate issuance, digital signatures, and the combined asymmetric‑symmetric handshake that make HTTPS a secure protocol for web communication.
This article explains why HTTPS is essential, compares symmetric and asymmetric encryption, illustrates how encryption keys are securely exchanged, and outlines the three core reasons HTTPS reliably protects data from eavesdropping and man‑in‑the‑middle attacks.
This article explains why HTTPS is considered secure, details its underlying cryptographic processes—including certificate verification, asymmetric and symmetric encryption, and the role of Certificate Authorities—while also addressing common misconceptions such as man‑in‑the‑middle attacks and packet capture.
The article explains why data security governance is essential for rapidly growing businesses, outlines technical goals across the data lifecycle, describes data classification and labeling methods, and details approval processes, network security zones, and management controls to protect data throughout its lifecycle.
This article breaks down the fundamental iptables command syntax, explains each option and parameter, provides practical examples for adding, inserting, listing, deleting, and managing firewall rules, and covers common modules, backup, and restoration techniques for effective Linux network security.
This article introduces iptables, explains its tables, chains, and packet‑processing flow, and provides step‑by‑step commands for installing and configuring the Linux firewall, offering a solid foundation for anyone new to network security on Linux systems.
The article explains recent GitHub access issues, defines man‑in‑the‑middle (MITM) attacks, describes how they work, lists common attack methods such as DNS spoofing and SSL stripping, and provides open‑source tools and blog resources for security professionals.
In late March, users in China reported errors accessing GitHub Pages and the main site, prompting investigations that suggest a possible man‑in‑the‑middle attack affecting GitHub’s services, with evidence such as a suspicious certificate issued to a QQ email, network hijacking on port 443, and similar disruptions across major Chinese ISPs, while the issue resolved by mid‑afternoon.
This guide explains multiple practical methods for discovering which ports are open on a Linux system, covering Nmap scans, Netcat probing, and Bash pseudo‑device checks, complete with command examples, option details, and output interpretation.
This guide explains what open ports are and provides step‑by‑step commands using Nmap, Netcat, and Bash pseudo‑devices to discover which TCP or UDP ports are listening on a Linux system, along with safety tips and example outputs.
iQIYI built QNSM, a DPDK‑based full‑traffic analysis engine for complex multi‑zone network boundaries, delivering high‑performance (10+ Gbps per NIC) real‑time detection of DDoS, IDPS, and DLP, with modular pipelines, Kafka integration, and open‑source deployment across 22 clusters.
This guide walks you through configuring OPNsense’s built-in OpenVPN module to create a site-to-site tunnel that securely connects the LANs of Beijing and Shanghai data centers, covering network architecture, server and client settings, firewall rules, NAT mapping, and verification steps.
This tutorial explains how to detect hidden Wi‑Fi networks by capturing router signals with airodump-ng, analyzing them with Python's Scapy library on Ubuntu, and extracting the SSID when a client connects, providing step‑by‑step instructions and essential tools.
This article explains the fundamentals of HTTPS by clarifying HTTP, SSL/TLS, and encryption types, describing HTTP's relationship with TCP and connection models, and outlining HTTPS's compatibility, extensibility, confidentiality, integrity, authenticity, and performance considerations.
This article explains the fundamentals of Linux iptables—including its role with netfilter, rule ordering, tables and chains—then walks through packet‑processing flows and three practical scenarios such as Envoy traffic hijacking, massive long‑connection handling, and bastion‑host security.
The article explains why enterprises adopt multi‑cloud strategies, outlines essential multi‑cloud management functions, discusses cloud‑network collaboration and security measures, and highlights future trends such as deep cloud‑network integration, data‑layer unification, consistent management, and edge‑cloud adoption.
Azure Virtual Network (VNet) is a private network in Azure that provides scalable, isolated address spaces, subnets, and region or subscription scopes, with best‑practice design guidelines, internet connectivity, inter‑resource communication, on‑premises integration via VPN or ExpressRoute, traffic filtering, routing options, and quota limits.
This guide explains how to set up Squid as an explicit or implicit forward proxy on Linux, covering SSL/TLS termination, required build tools, user creation, compilation options, CA generation, detailed squid.conf settings, and necessary iptables NAT rules.
On the internet’s 50th anniversary, UCLA professor Leonard Kleinrock recounts the pioneering packet‑switching breakthrough, the first ARPANET transmission, and warns that the original open, ethical ethos has been eclipsed by commercialization, security threats, and the urgent need for collective responsibility.
Tencent led the creation of the world’s first zero‑trust security standard at the ITU‑T SG17 meeting, detailing the concept, its industry impact, and real‑world deployments across sectors such as government, healthcare, transportation, and finance.
This article explains what HTTPS is, why it adds encryption to HTTP, how SSL/TLS, symmetric and asymmetric cryptography, certificates, and handshakes work together to ensure confidentiality, integrity, and authenticity, and discusses the performance impact of HTTPS connections.
The 7th Internet Security Conference in Beijing gathered international experts to discuss the merging of cyberspace and physical space, the heightened impact of 5G and industrial IoT on cyber attacks, and collaborative strategies among China, Israel, Russia, and Singapore to build a comprehensive security ecosystem.
The article explains the fundamental differences between intrusion detection systems (IDS), intrusion prevention systems (IPS), and unified threat management (UTM) devices, covering their detection methods, placement strategies, operational trade‑offs, and maintenance requirements to help security professionals choose and manage the appropriate solution.
In a Sanya digital summit speech, Zhou Hongyi warned that cyber warfare has become a major national‑level threat, outlined four key shifts in enterprise security, and described 360's big‑data security brain and future plans to build a nation‑wide defensive ecosystem.
This document outlines the background, challenges, and a comprehensive enterprise intrusion detection solution that combines host‑based and network‑based monitoring, automated CVE and GitHub leak collection, a modular agent‑middle‑display architecture, and future plans for multi‑dimensional threat modeling to enhance preventive security capabilities.
This guide walks you through using Linux's two main firewall tools—firewalld for CentOS 7+ and iptables for older versions—covering installation, service control, rule management, port handling, and useful commands with clear examples and screenshots.
The article explains the security risks of plain HTTP, introduces symmetric and asymmetric encryption, describes digital certificates, certificate authorities, digital signatures, and how they combine in HTTPS to protect data confidentiality, integrity, and authenticity during web communication.
The paper examines novel TCP reflection DDoS methods that exploit CDN IP ranges and increasingly use pure ACK responses, outlines their handshake‑state behavior, and proposes a per‑connection tracking defense algorithm—implemented in Tencent’s DaYu platform—to detect and mitigate SYN/ACK, ACK, and RST reflection flows without affecting legitimate traffic.
This guide explains seven practical SSH techniques—including basic login, custom ports, compression, debugging, source address binding, remote command execution, and mounting remote filesystems—providing clear examples and command syntax for secure and efficient Linux server administration.
This article explains what proxy servers are, why they are used to improve speed, enhance security, and bypass restrictions, and details the concepts, functions, and distinctions between forward proxies and reverse proxies, including their roles in caching, load balancing, and network protection.
This article explains the definitions, real‑world analogies, practical applications, and fundamental differences between forward (client‑side) and reverse (server‑side) proxy servers, helping developers and operators grasp why these concepts matter for access control, performance, and security.
This article presents a comprehensive collection of network security mind maps covering introductory concepts, scanning and defense techniques, monitoring, password cracking, deception attacks, denial-of-service, buffer overflow, web, trojan, virus threats, and future trends, guiding learners through a structured technical roadmap.
Google Public DNS now fully supports DNS over HTTPS, enhancing privacy and security with minimal performance impact, while the article explains why DNS needs encryption, how DoH works, browser support, and practical considerations for adoption.
This article explains the concept of operations security, why it has become critical, enumerates common mis‑configurations and vulnerabilities such as open ports, weak permissions, insecure scripts and supply‑chain risks, and provides a comprehensive set of best‑practice guidelines and an enterprise‑level framework to build a resilient operations security posture.
This guide presents a collection of commonly used Linux iptables rules—ranging from deleting existing rules and setting default policies to allowing specific services like SSH, HTTP, HTTPS, and configuring port forwarding, logging, and DoS protection—so you can tailor firewall settings to your environment.
The 2018 second‑quarter report by the Ministry of Industry and Information Technology details the monitoring of approximately 18.4 million internet security threats, highlighting compromised user email accounts, attacks on industrial IoT platforms and devices, the rise of illegal cryptocurrency mining, and outlines the major mitigation actions taken, including vulnerability remediation, network protection for major events, and coordinated emergency drills.
This article explains the principles of port scanning, lists common service ports and their states, demonstrates nmap usage, and provides both single‑threaded and multithreaded Python scripts for port scanning, followed by three Python‑based subdomain collection methods and two approaches for CMS fingerprinting, complete with code examples.
This article explains the fundamentals of HTTPS by clarifying key terms such as HTTP, SSL/TLS, and encryption, describing how HTTP works over TCP, the differences between symmetric and asymmetric cryptography, and the core security requirements of confidentiality, integrity, authenticity, and performance.
In the first half of 2018 DDoS attacks surged, with IoT‑based SSDP and newly dominant Memcached reflection amplifications reaching 1.7 Tbps, gaming becoming the top‑targeted sector, SYN and HTTP floods rising, attack infrastructure shifting abroad, and automated, low‑cost services enabling teenage operators, prompting recommendations for high‑bandwidth cloud and BGP defenses.
Recent DDoS campaigns are using UPnP protocol flaws to hide source‑port information, allowing amplification attacks such as DNS spoofing to evade traditional defenses by routing traffic through compromised IoT routers and manipulating port‑forwarding rules via SOAP requests.
This tutorial explains two practical methods for cracking Wi‑Fi passwords using Python—first by leveraging the pywifi library with custom dictionaries and scanning scripts, and second by employing the Wifiphisher tool to create a rogue access point and capture credentials.
This article explains what a Man‑in‑the‑Middle (MITM) attack is, illustrates it with a classic mailbox analogy, and describes how HTTPS, digital certificates, and the HSTS policy work together to prevent such attacks and ensure secure web communications.
