This comprehensive guide answers 100 common networking questions, covering links, the OSI model, backbone networks, LAN, routers, protocols, IP addressing, security measures, cable types, topologies, and many other essential concepts for anyone studying computer networks.
This article explains three IP load‑balancing techniques used in Linux Virtual Server—VS/NAT, VS/DR, and VS/TUN—detailing their architectures, packet‑rewriting processes, configuration examples, performance characteristics, and a comparative analysis of their strengths and weaknesses.
This article examines the difficulties of running stateful services such as Redis, etcd, and MySQL on Kubernetes and presents practical solutions—including workload selection, CRD/operator extensions, scheduling strategies, high‑availability mechanisms, performance‑optimized networking and storage, and chaos‑engineering validation—to achieve reliable, high‑performance containerized deployments.
This comprehensive guide explains when to employ multiple routing protocols, compares distance‑vector and link‑state routing, details access‑list types and creation commands, outlines route redistribution steps and commands, clarifies administrative distance, BGP fundamentals, metric concepts, and provides hardware compatibility notes for Cisco routers and switches.
On Linux, the client port used in a TCP connection is selected either by the kernel during the connect system call—randomly scanning the ip_local_port_range while respecting reserved ports—or by a prior bind call, with detailed kernel functions such as inet_hash_connect and __inet_hash_connect governing the process.
The article provides a full‑length technical exam covering multiple‑choice questions on programming history, algorithms, networking and 5G, short answer queries about design patterns and tree operations, and coding challenges that ask participants to implement solutions for counting ways to eat bread, climb stairs, and analyze a C program that counts cycles in a permutation.
This article provides a comprehensive overview of the Domain Name System (DNS), covering its fundamentals, protocol choices, hierarchical structure, delegation, configuration with BIND, load balancing, debugging tools, and security considerations such as amplification attacks.
This article provides concise explanations of core networking concepts, covering links, OSI model layers, backbone networks, LANs, nodes, routers, point‑to‑point links, FTP, subnet masks, UTP cable limits, data encapsulation, network topologies, VPN, NAT, routing protocols, firewalls, DNS, IPv6, RSA, and many other fundamental topics essential for anyone studying computer networks.
An intermittent 403 error caused by nginx reuseport misrouting on a shared IP was traced to kernel listener hash table ordering; upgrading the Linux kernel from 4.14 to 4.16+ resolved the issue by prioritizing IP+PORT over INADDR_ANY lookups.
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 guide explains DNS fundamentals, its distributed hierarchical database, TCP/UDP usage, top‑level domains, resolution workflow, recursive versus authoritative servers, caching, smart routing, bind configuration, load balancing, sub‑domain delegation, debugging tools, and DNS amplification attacks.
This article provides a comprehensive overview of Kubernetes, covering its core components, container operations, service discovery layers, pod shared resources, common CNI plugins, multi‑layer load balancing, isolation dimensions, network model principles, and various IP address categories for large‑scale deployments.
This guide explains why Python is the de‑facto language for vulnerability development, covering environment isolation with virtualenv/venv, package installation via pip, key libraries for networking, binary manipulation, encoding, and introduces pwntools for exploit creation.
This article provides a comprehensive overview of the Domain Name System (DNS), covering its distributed database design, TCP/UDP usage, hierarchical structure, top‑level domains, resolution workflow, recursive versus authoritative servers, caching, smart routing, BIND configuration, load‑balancing techniques, sub‑domain delegation, debugging tools, and security considerations such as DNS amplification attacks.
This article explains the DNS system, its distributed architecture, protocol details, hierarchical database structure, resolution process, server types, configuration with BIND, load balancing, subdomain delegation, and security considerations such as amplification attacks, providing a comprehensive guide for operations and networking professionals.
This article provides a comprehensive guide to TCP’s core mechanisms, covering connection establishment via the three‑way handshake, graceful termination with the four‑step teardown, half‑open and half‑close scenarios, simultaneous open/close, initial sequence numbers, and detailed state‑transition diagrams, all illustrated with diagrams.
This article explains the complete process from entering a URL to rendering a web page, covering URL parsing, DNS resolution, TCP three‑way handshake and four‑way teardown, HTTP request/response structure, and browser rendering, while also clarifying TIME_WAIT and related socket states.
This article explains the concepts of blocking (BIO), non‑blocking (NIO) and asynchronous (AIO) I/O in Java, introduces the principle of I/O multiplexing, provides a complete Java example with server and client code, and compares system calls like select, poll, and epoll.
This guide explains how kube-proxy in iptables mode, together with Calico BGP routing, translates service IPs to pod IPs, creates custom iptables chains, and routes traffic from external or node ports to the correct pod across a Kubernetes cluster.
The article explains why accessing Zhihu with its raw IP address is blocked while domain access works, covering CDN sharing, the importance of hostnames, and how the TLS SNI extension lets servers identify the intended website before establishing a connection.
This article explains the limitations of NAT and FULLNAT load‑balancing models, introduces DR and TUN modes that let real servers reply directly to clients, and details the required ARP and loopback configurations to hide VIPs and reduce bottlenecks.
This comprehensive guide introduces Python fundamentals, covering file encoding declarations, shebang usage, quicksort implementation, script entry checks with __name__, printing differences between Python 2 and 3, pretty‑printing, module and package structures, control flow statements, data types, string operations, regular expressions, collections, dictionary handling, functional tools, generators, decorators, class definitions, property management, exception handling, unit testing, file and path manipulation, JSON/XML processing, Excel interaction, file system utilities, network requests, and MySQL database access.
At an April 10 technical salon, iQIYI’s Zhao Wei detailed the company’s shift from Mesos‑Marathon to Kubernetes, describing container application scenarios, evolving network stacks from bridge/NAT to Cilium/BGP, the adoption of Containerd with RunC and optional Kata runtimes, performance trade‑offs, and a hybrid scheduling approach that improves resource utilization across offline and online services.
This article explains why real‑time audio/video communication prefers UDP over TCP, compares TCP and UDP characteristics, introduces the RTP and RTCP application‑layer protocols that enable reliable media transport, and provides a quick Wireshark guide for capturing and analyzing RTP/RTCP packets.
This article provides an extensive overview of the HTTP protocol, covering its layered network architecture, request/response processes, detailed header fields, caching directives, status codes, message bodies, as well as related components such as cookies, proxies, and servers.
This article provides a comprehensive overview of the HTTP protocol, covering its definition, stateless nature, connection handling, key characteristics, request/response workflow, header fields, status codes, caching mechanisms, and practical applications such as resumable downloads, multithreaded downloading, proxy servers and virtual hosting.
This article explores three real‑world cases of TCP anomalies that affect database connectivity—ineffective RST packets, unexpected port exhaustion despite tcp_tw_reuse, and ghost connections caused by a full accept queue—explaining the underlying Linux kernel mechanics and offering practical mitigation strategies.
This article explains how two computers locate each other on the Internet using IP, MAC, and port numbers, details the ARP protocol and routing table lookup, and then examines LVS load‑balancing mechanisms, comparing NAT and FULLNAT models and their packet‑translation processes.
An in‑depth guide covering Java reflection fundamentals, three methods to obtain Class objects, and practical code examples, followed by a comprehensive overview of computer networking layers, protocols, TCP/IP versus OSI models, transport protocols, HTTP/HTTPS differences, status codes, GET/POST, cookies, sessions, tokens, and servlet lifecycle.
This article clarifies the differences between Layer‑2 and Layer‑3 interfaces, explains VLANIF and PVID concepts, and details how access, trunk, and hybrid ports handle VLANs, providing practical insights for network engineers dealing with Ethernet switching and routing configurations.
This article explains the origins, types, and inner workings of load balancing—including DNS, hardware, and software solutions—covers the Linux Virtual Server (LVS) architecture, netfilter fundamentals, and compares DR, NAT, and Tunnel modes with their advantages, drawbacks, and ideal use cases.
This article walks through the complete process of how a browser accesses a web resource, from parsing a URL and generating an HTTP request, through DNS name resolution, the construction of MAC, IP, TCP, and application headers, to the TCP three‑way handshake, data transmission, and the four‑step connection termination.
This article reviews the evolution of HTTP from version 1.1 to HTTP/2 and HTTP/3, explaining key features such as persistent connections, pipelining, binary framing, header compression, multiplexing, and QUIC's advantages, while also highlighting the remaining drawbacks like head‑of‑line blocking, TCP connection limits, and security concerns.
This article explains the background of Server Load Balancing (SLB), details its three transmission modes—reverse proxy, transparent, and triangle—illustrates packet interactions with TCP and HTTP flows, and provides analysis of each mode using Wireshark captures.
This article explains Java NIO fundamentals—including Channels, Buffers, and Selectors—compares them with traditional IO, and provides multiple runnable code examples such as FileChannel, SocketChannel, Selector loops, memory‑mapped files, scatter/gather, transferTo/From, Pipe and DatagramChannel to illustrate non‑blocking and high‑performance I/O.
This article explains the Kubernetes pod network concept, describing how each pod receives a unique IP, how intra‑node and inter‑node pod communication works, and the role of the infra container and network bridges in enabling seamless IP addressing across the cluster.
This article provides a comprehensive overview of the Domain Name System, explaining how hostnames map to IP addresses, the hierarchical distributed design of DNS servers, query processes, caching mechanisms, packet structures, common attack vectors, and defensive measures such as DNSSEC.
This article explains how to implement a TCP heartbeat mechanism using Netty's IdleStateHandler, details client and server handler implementations, and demonstrates a robust reconnection strategy with customizable retry policies, providing complete Java code examples for each component.
The article uses a courtyard and gatekeeper metaphor to explain the roles of gateways, DNS, DHCP, routing tables, static and dynamic routing, route selection, IP/MAC addressing, ARP spoofing, DDoS/DoS attacks, and related security concepts in computer networking.
This article explains how KubeVirt extends Kubernetes to manage virtual machines, covering the background of OpenStack‑to‑K8s migration, technical selection, KubeVirt architecture, CRDs, components, common operations, storage and networking choices, SDK usage, and practical deployment experiences within a private cloud platform.
This comprehensive guide explains TCP fundamentals—including the differences between TCP and UDP, the three‑way handshake, four‑way termination, half‑open queues, SYN‑Flood attacks, header fields, Fast Open, timestamps, retransmission timeout calculation, flow and congestion control, Nagle's algorithm, delayed ACKs, and keep‑alive mechanisms—providing clear examples and diagrams for each concept.
This article explains how Linux manages TCP sockets at the kernel level, demonstrates how to adjust port ranges and file‑descriptor limits, and shows the key data structures and lookup functions that enable high‑concurrency TCP connections, providing practical guidance for scaling client connections.
This comprehensive guide explains DNS fundamentals, hierarchical server architecture, query processes, packet structure, caching mechanisms, and common security threats, providing clear examples, diagrams, and practical insights for anyone preparing for networking interviews or deepening their understanding of internet name resolution.
This article provides a detailed overview of Docker, covering its origins, core components such as images, containers, and repositories, the differences between VMs and containers, integration with DevOps and Kubernetes, networking modes, storage layers, and visual management tools, all illustrated with examples and code snippets.
The libp2p‑rs update introduces beta‑value termination for Kad‑DHT queries, timeout mechanisms, routing table refresh, node keep‑alive, identify event handling, outbound sub‑stream reuse, query statistics, a debuggable CLI, and adds experimental floodsub, mdns, parallel dialing, Prometheus exporter, and other enhancements.
This guide shows how to increase the number of concurrent TCP connections on a Linux server by adjusting kernel parameters, expanding file descriptor limits, and understanding the underlying socket structures and lookup mechanisms that govern connection handling.
This article explores Linux’s TCP socket implementation, showing how to adjust system limits, dissecting key kernel structures like sock_common, and walking through the tcp_v4_rcv processing path and inet lookup functions, ultimately revealing methods to scale client connections beyond the traditional 65 535 port limit.
This article explains the background of server load balancing (SLB), compares layer‑4 and layer‑7 approaches, and details the three SLB transmission modes—reverse proxy, transparent pass‑through, and triangle—including packet‑level analysis and practical considerations.
This article traces the evolution of HTTP from its 1991 origins through HTTP/1.0, 1.1, SPDY, and HTTP/2, explaining why the shift to UDP‑based QUIC in HTTP/3 promises faster, more secure web delivery while also highlighting the new protocol’s challenges.
This article explains the principles, use cases, and kernel implementation of Linux connection tracking (conntrack), covering its role in NAT, L4 load balancing, Netfilter hook mechanisms, key data structures, core functions, and performance considerations.
This article explains the fundamentals of the Domain Name System (DNS), covering how domain names map to IP addresses, the hierarchical structure of DNS zones, the roles of root, top‑level, and authoritative servers, query processes, record types, and practical command‑line tools like dig and ipconfig.
This article explains how to adjust Linux kernel port ranges and file descriptor limits, explores the internal structures of TCP sockets, and walks through key kernel functions such as tcp_v4_rcv and __inet_lookup that locate sockets based on IP and port tuples, providing practical guidance for increasing TCP concurrency.
This article explains the definitions and interactions of Trunk, Hybrid, and Access ports, the concepts of VLAN tagging, untagging, and PVID, and demonstrates their behavior on Huawei switches through detailed configuration examples and traffic flow analysis.
This article presents an illustrated comic that explains the basic principles of the TCP protocol, highlighting its connection-oriented reliable transmission, congestion and flow control mechanisms, while noting that some details are simplified and encouraging readers to consult formal RFCs and the TCP/IP Illustrated volume for deeper study.
This guide provides a concise reference of curl's most useful command‑line options, explaining how to customize headers, handle cookies, send data, manage redirects, control output, and debug requests for efficient web and API interactions.
This article explains the fundamentals of the Domain Name System, walks through the multi‑stage DNS query process using the dig tool, describes the hierarchy of domain names, the role of root and authoritative servers, and introduces common DNS record types and useful command‑line utilities.
The article explains how ARP and MAC address table aging, switch learning policies, and LVS tunnel mode can cause unknown unicast flooding, describes the resulting bandwidth issues in a data‑center environment, and proposes configuration changes to eliminate the flooding.
This guide explains how to configure multiple VLAN‑tagged interfaces on a single Linux network card in CentOS/RHEL, covering kernel module loading, creating VLAN interfaces with ip, assigning IP addresses, and persisting the settings via ifcfg files so they survive reboots.
This comprehensive guide walks you through the TCP/IP protocol suite—covering the four‑layer model, key protocols like IP, ARP, ICMP, DNS, the mechanics of ping and traceroute, TCP/UDP differences, connection establishment and termination, flow control, and congestion control—providing the core knowledge needed for networking interviews and solidifying fundamental networking concepts.
This comprehensive guide walks through TCP fundamentals—including its differences from UDP, the three‑way handshake, four‑way termination, half‑open queues, SYN‑Flood attacks, packet header fields, Fast Open, timestamps, RTT/RTO calculations, flow and congestion control, Nagle's algorithm, delayed ACKs, and keep‑alive mechanisms—providing clear explanations and visual diagrams for each concept.
This article demystifies the true maximum number of concurrent TCP connections a single Linux server can sustain, explaining the theoretical limits of the TCP four‑tuple, the practical constraints imposed by file descriptor and memory settings, and walks through a real‑world experiment achieving one million connections.
This article explains what a data center is, its core components of compute, storage, and networking, the operational and architectural considerations for reliability and security, and reviews industry standards and emerging technologies such as edge computing, cloud integration, SDN, HCI, containers, NVMe, and GPU acceleration.
This article uses everyday analogies to compare UDP and TCP, outlines their core characteristics, typical use cases, and describes how to add TCP-like reliability features to UDP such as connection establishment, ordering, loss recovery, flow control, and congestion control.
This article walks through the design and implementation of a Java Socket.IO client library, covering dependency setup, core class architecture, event handling, connection management, performance testing utilities, and a complete usage demo with console output.
This article provides a comprehensive introduction to the transport layer of computer networks, explaining the roles of TCP and UDP, socket APIs, port numbers, multiplexing, packet structures, connection management, three‑way handshake, four‑way termination, and congestion‑control mechanisms.
This article explains how Kubernetes networking components—including the container runtime, CRI, CNI plugins, Flannel, and node IPAM—work together to assign unique IP addresses to each Pod across a cluster, covering both same‑host and cross‑host communication mechanisms.
This article explains the history, standards, layered architecture, and step‑by‑step packet transmission of the TCP/IP suite, detailing each protocol’s role from the physical link up to the application layer and illustrating how data traverses the network.
This article provides a comprehensive overview of the transport layer in the TCP/IP model, explaining the roles of TCP and UDP protocols, socket APIs, port numbers, multiplexing, and how data is encapsulated and transmitted between end systems.
This article walks through the complete lifecycle of a network request, explaining URL structure, HTTP methods and headers, DNS query mechanics, socket programming, TCP/IP communication, firewall filtering, and various load‑balancing strategies in clear, step‑by‑step detail.
Flannel, a Kubernetes CNI plugin, creates a host overlay network using VXLAN to assign unique virtual IPs to pods, encapsulate traffic, and coordinate routing via etcd, with detailed explanations of its components, packet flow, and underlying Linux networking mechanisms.
This guide explains how Docker uses -p and -P options for port mapping, how to bind specific host IPs and protocols, view mappings, combine multiple bindings, and expose un‑mapped containers later via host iptables NAT rules for full network access.
This article explains the TCP three‑way handshake and four‑way termination processes, clarifies the TIME_WAIT state, shows how to inspect socket states with netstat, and provides practical Linux sysctl settings to reduce excessive TIME_WAIT sockets and improve network performance.
This article compiles a series of technical interview questions and answers covering MySQL query best practices, index optimization, B+‑tree storage, binlog recovery, master‑slave replication, design pattern usage in Laravel, a PHP binary‑search insertion algorithm, transport‑layer protocols, TCP three‑handshake, and concurrency control strategies.
This article presents ten practical Linux system‑administration techniques—from ejecting a stuck DVD drive and resetting a frozen console to using screen sharing, SSH tunnels, bandwidth testing, and powerful command‑line scripts—each designed to streamline tasks, reduce downtime, and give administrators more free time.
This article explains the basic networking devices and concepts—including hubs, switches, routers, gateways, routing, static vs. dynamic routing, routing tables, and the differences between bridging and routing—illustrated with diagrams and step‑by‑step examples to clarify how data moves across networks.
This article provides a concise overview of Kubernetes, covering its master‑node architecture, core components such as API server, scheduler, controller, kubelet and kube-proxy, the lifecycle of Deployments and Pods, and explains service types, networking, and service discovery within a cloud‑native environment.
This article explains the fundamental distinctions between HTTP GET and POST requests, covering how parameters are transmitted, browser and server behaviors, length limits, security implications, underlying TCP mechanics, and performance trade‑offs, while also debunking common misconceptions often seen in interview answers.
This guide presents ten practical Linux system‑administration tricks—from unmounting a stuck DVD drive and resetting a frozen console to using screen for collaborative debugging, recovering a lost root password, creating SSH backdoors, tunneling VNC, measuring bandwidth, and automating host‑file generation—helping admins work faster and smarter.
This article details the design and implementation of a Java chat system that uses Netty for server‑side networking, Swing for the client UI, and MySQL with C3P0 for data persistence, covering features such as user authentication, friend management, single‑chat messaging, and online status detection.
This article provides a detailed walkthrough of MySQL protocol analysis using Wireshark, covering SSL disabling, packet capture commands, step‑by‑step examination of handshake, authentication, database selection, query execution packets, and an in‑depth look at related source‑code functions and command enums.
This article provides a comprehensive overview of the TCP/IP protocol suite, covering its historical origins, standardization principles, the four-layer model, detailed functions of each layer, and the step‑by‑step process of how a data packet traverses from the application layer down to the physical link.
RoCE (RDMA over Converged Ethernet) enables lossless, high‑performance data transfer in data‑center networks by extending InfiniBand over Ethernet, with RoCEv1 operating at Layer 2, RoCEv2 adding UDP/IPv4/IPv6 routing, and Soft‑RoCE providing a software‑only solution for environments lacking RDMA‑capable hardware.
This guide explains how Flannel works as a Kubernetes CNI overlay network, detailing its VXLAN mode, the roles of cni0, flannel.1 and flanneld, routing and FDB handling, and provides command‑line examples to trace pod‑to‑pod traffic across nodes.
This article provides a detailed introduction to the TCP/IP model, explaining each layer—from the physical and data link layers up to the application layer—along with key protocols such as IP, ARP, ICMP, TCP, UDP, DNS, and the mechanisms of connection establishment, termination, flow control, and congestion control.
This article explains the fundamentals of the Domain Name System (DNS), detailing how domain names are translated into IP addresses, the multi‑step query process, the role of DNS servers, hierarchical naming, record types, and useful command‑line tools for inspection.
EndpointSlices replace the traditional Endpoints API in Kubernetes, offering a scalable, slice‑based approach that reduces data transfer, enables features like dual‑stack services and topology‑aware routing, and allows clusters to handle hundreds of thousands of network endpoints efficiently.
During high‑concurrency traffic, servers can accumulate large numbers of TCP connections in the TIME_WAIT state, which can exhaust local ports and cause “address already in use” errors; this article explains the phenomenon, its underlying TCP mechanics, and practical configuration and kernel tweaks to mitigate the issue.
This article explains the fundamental distinctions between GET and POST HTTP methods, covering how parameters are transmitted, browser and server constraints, underlying TCP behavior, and why POST often requires two TCP packets while GET typically uses only one.
Linux 5.10 brings a slew of network upgrades—including bundled BPF programs, support for over 255 IPv4 multicast interfaces, MPTCP refinements, Intel IGB XDP support, new Wi‑Fi driver chips, up to 20% performance gains for Mellanox NICs, and a BPF helper that boosts TCP throughput from 10 Gbps to 15 Gbps.
This comprehensive guide explains computer networking fundamentals, covering the OSI seven‑layer model, TCP/IP suite, IP addressing, subnet masks, ARP/RARP, routing protocols, TCP handshakes, UDP, DNS, NAT, DHCP, HTTP methods, and a practical example of accessing a website.
This guide presents an extensive collection of Linux commands covering file and directory operations, content viewing, compression, system information, networking, user management, permissions, process control, and system monitoring, each explained with its purpose and typical usage in clear English.
This article explains the fundamental similarities and practical differences between HTTP GET and POST requests, covering how parameters are transmitted, caching behavior, URL length limits, security considerations, underlying TCP mechanics, and the impact on performance and semantics.
This article explains how modern web services rely on server clusters and a front‑end load balancer, compares the three most popular software balancers—LVS, Nginx, and HAProxy—by describing their architecture, operating modes, advantages, and drawbacks, and offers guidance on selecting the appropriate solution for different traffic scales.
This guide explains multiple practical techniques—including mirror sites, Cloudflare Workers proxies, Chrome extensions, JsDelivr, Gitee forks, and hosts file modifications—to significantly speed up GitHub repository cloning, release downloads, and raw file access for users facing slow connections.
This article provides a thorough introduction to computer networking fundamentals, covering the OSI seven‑layer model, TCP/IP architecture, IP addressing, subnet masks, ARP/RARP, routing protocols, and key application layer protocols such as DNS, HTTP, and DHCP, with practical examples and diagrams.
This article provides a thorough introduction to computer networking, covering its historical evolution, classification, topology, performance metrics, OSI and TCP/IP models, physical and data‑link layer technologies, key protocols such as IP, ARP, NAT, TCP/UDP, and application‑layer services like HTTP, FTP, DNS, and DHCP, offering readers a solid foundation for self‑study and interview preparation.
The article explains why massive TIME_WAIT sockets appear during high‑concurrency traffic, how they can exhaust local ports and cause connection errors, and provides practical server‑side and client‑side configurations to mitigate the issue.
This article offers a comprehensive overview of network switches, detailing their classifications, performance indicators, interface and link methods, virtual LANs, multilayer switching, and product introductions, providing essential knowledge for anyone studying networking fundamentals.
This article explains how Kubernetes Service and Ingress resources work as layer‑4 and layer‑7 schedulers, covering Service types, kube‑proxy modes, YAML definitions, and TLS‑enabled Ingress configuration with practical command‑line examples.
This tutorial introduces Python's Requests library, covering installation, basic GET and POST requests, adding headers and parameters, handling proxies, cookies, sessions, and disabling SSL verification, with clear code examples for each feature.
