This article walks through a systematic network troubleshooting workflow on Linux, detailing how to use ss to inspect sockets, ip for routing and address information, tc for traffic control at the link layer, and ethtool for hardware diagnostics, with concrete command examples and practical tips.
This guide walks Linux administrators through nine core networking utilities—ip, netstat, nmap, traceroute, tcpdump, ssh, wget, netplan, and nmtui—explaining their purpose, key options, and example commands to configure interfaces, inspect routes, capture packets, and manage remote connections.
In multi‑node OCP deployments, accessing monitoring data via the master node IP/VIP can trigger a 401 "invalid VIP" error, and this guide explains the root cause, how OCP validates source IPs, and provides two reliable methods to correct the source IP configuration.
This guide walks through Linux network fundamentals, covering hostname, IP address, netmask, gateway, DNS, interface status, routing tables, and tools like ifconfig, ip, route, ss, netstat, traceroute, nslookup, tcpdump, as well as temporary and permanent IP changes, interface renaming, dual‑NIC bonding, and practical command examples.
This comprehensive guide walks readers through the fundamentals of computer networking, covering architecture models, TCP and UDP protocols, HTTP basics, socket programming, IP addressing, ICMP, Ping, and related concepts such as routers, cookies, and token authentication, all illustrated with clear diagrams.
This article explains the fundamentals of Network Address Translation (NAT), including IPv4 address exhaustion, private IP ranges, NAT principles, roles, classifications such as static NAT, dynamic NAT, NAPT, Easy IP, NAT Server, and provides detailed configuration examples and a typical network experiment to illustrate practical deployment.
This article explains the structure of IP packets, the role and encapsulation process of the ICMP protocol, the function and operation of ARP, and how ARP spoofing attacks manipulate MAC addresses to disrupt network communication.
This comprehensive guide walks you through Linux routing fundamentals, table structures, static and dynamic configurations, as well as advanced techniques like policy routing and ECMP, as well as troubleshooting, performance tuning, security measures, and best practices, enabling you to become a network expert in just three days.
This guide walks through Linux network fundamentals—including hostname, IP address, netmask, gateway, DNS, interface status, temporary and permanent IP changes with ifconfig and ip, routing adjustments, bond interface setup, and diagnostic utilities like ethtool, ss, netstat, traceroute, nslookup, and tcpdump—providing step‑by‑step commands and examples for effective system administration.
This article explains Linux routing fundamentals, describing how routing tables are used to select interfaces and next hops, detailing the six-step packet routing process, and providing step‑by‑step commands and examples for adding and removing host, network, and default routes on Linux systems.
This article explains the fundamentals of IP routing in data communication networks, covering how routers use routing tables, route information, direct routes, priority and metric calculations, longest‑prefix matching, and the step‑by‑step forwarding process with practical examples and command snippets.
This article explains the structure of IP packets, the role and encapsulation of the ICMP protocol, how ARP resolves IP addresses to MAC addresses, and the principles behind ARP spoofing attacks, providing a concise overview of essential network-layer concepts.
This article explains how IP packets are encapsulated, how TTL limits their lifespan, and how traceroute (or tracert) leverages TTL to reveal each network hop, illustrated with a step‑by‑step trace from a personal computer to GitHub’s servers.
This guide explains what network‑card promiscuous (promisc) mode is, why it matters for receiving packets across different subnets, and provides step‑by‑step Linux commands and a C program example to enable, disable, and verify the mode on an interface.
The article walks through every stage of a web request—from IPv4 addressing, NAT, and DNS resolution through CDN proximity and TCP stream handling, to HTTP framing, CGI versus FastCGI processing, stateless versus stateful server models, and finally database scaling techniques such as sharding and Redis caching.
This guide explains how to install, use, and interpret the Linux route command for displaying and manipulating the kernel IP routing table, covering options, output fields, persistence tricks, and practical examples for querying, adding, deleting, and rejecting routes.
This guide explains how to enable VLAN tagging on a Linux server, create VLAN interfaces for different subnets, assign IP addresses, and make the configuration persistent on CentOS/RHEL systems using kernel modules, ip commands, and network‑script files.
The IPv4 loopback address 127.0.0.1 (also reachable via the hostname localhost) is reserved for internal communication, so pinging it never leaves the host and works even with the network cable unplugged, while 0.0.0.0 is an unspecified address used only for binding to all interfaces and cannot be pinged.
This comprehensive guide covers the network layer fundamentals, including classful and classless IP addressing, IP packet structure, routing concepts, ARP/RARP, ICMP, DHCP, major routing protocols, multicast mechanisms, VPN, NAT, mobile IP, and essential command‑line tools.
This article provides a comprehensive overview of core network protocol structures—including TCP, UDP, IPv4/IPv6, IPSec, Ethernet, 802.1Q, 802.11, SSL, RTP, and OpenFlow—detailing their header fields, functions, and security mechanisms to help readers grasp essential networking concepts.
This article explains the technical distinction between bandwidth and broadband, shows how to convert bandwidth to download speed, clarifies upstream and downstream rates, discusses server bandwidth usage, and compares private and public IP addresses with practical examples and calculations.
This guide explains how to retrieve the true client IP in environments with multiple proxy layers by understanding remote_addr, X-Forwarded-For, and X-Real-IP headers, and configuring HAProxy and Nginx Ingress with appropriate options to forward and preserve the original IP.
This article explains Suricata's packet‑decoding pipeline, detailing how Ethernet frames, IP datagrams, TCP segments and UDP datagrams are parsed from raw traffic, and shows the relevant source‑code structures used in the open‑source IDS.
This article explains what happens when a client attempts a TCP connection to an IP address that does not exist or to a valid IP where the target port is not listening, covering ARP failures, SYN retransmissions, RST responses, and the importance of solid networking fundamentals for interview preparation.
This article explains why home networks use private 192.168.x.x addresses, how NAT devices translate private to public IPs, the roles of SNAT and DNAT, the extension to NAPT with port translation, and techniques such as NAT traversal and hole punching that enable inbound connections from the Internet.
This guide lists six Linux networking commands that have been deprecated—ifconfig, netstat, scp, route, egrep/fgrep, and arp/iptunnel/nameif—and shows the modern ip, ss, sftp/rsync, and grep alternatives with usage examples and brief explanations.
This article explains the two kinds of broadcast IP addresses—local broadcast (255.255.255.255) and directed broadcast (e.g., 10.1.1.255)—detailing their Layer‑2 and Layer‑3 behaviors, packet structures, Wireshark analysis, security implications, and how they are used in real networks.
This comprehensive guide explains the TCP/IP model’s four layers, key protocols such as IP, ARP, ICMP, DNS, and the differences between TCP and UDP, and details connection setup, termination, flow and congestion control mechanisms like slow start, fast retransmit, and fast recovery.
This guide details how to modify Ceph monitor (MON) IP addresses when moving a Ceph cluster to a new data center, covering both same‑network IP changes by adding and removing MON nodes and full‑network IP updates using monmaptool, with step‑by‑step commands and troubleshooting tips.
This article uses vivid school analogies and detailed diagrams to explain how computers communicate over networks, covering concepts such as hosts, subnets, IP and MAC addresses, subnet masks, ARP, DHCP, routing, and NAT, helping readers grasp both basic and advanced networking principles.
The article explains how chiplet technology, as a modular semiconductor IP solution, reduces design cost and time, expands market opportunities, and faces challenges such as standardization, packaging testing, and software integration, while outlining its market outlook and impact on business models.
This article explains the layered structure of computer networks, the role of IP, TCP, HTTP and DNS, and dives into Ethernet basics, collision handling, switches, and how diverse networks interconnect to form the Internet, providing a comprehensive overview for developers.
This article explains how computers communicate over networks by introducing MAC addresses, the role of hubs and switches, the function of routers, IP addressing, subnet masks, ARP, and routing tables, illustrating the process of data transmission across different network layers.
This guide explains how to use Linux networking commands—including ip, ifconfig, netstat, ping, traceroute, host, dig, systemd-resolve, and dhclient—to inspect interfaces, check connectivity, trace routes, query DNS, and manage DHCP leases for effective troubleshooting.
This tutorial walks through creating and configuring a Linux bridge, connecting it to veth pairs and a physical NIC, assigning IPs, troubleshooting ARP issues, and demonstrates common use cases for virtual machines and Docker containers.
This article explains the fundamental mechanisms of computer networking—including IP addressing, MAC addresses, ARP, DHCP, subnetting, routing, and NAT—using clear analogies and detailed diagrams to help readers grasp how data travels from one host to another across local and wide-area networks.
This article explains how to obtain a user's city from their IP address in a Java Spring backend, using the QQWry IP database, custom utility classes, and a login interceptor to count visits per city, with complete code examples and deployment considerations.
This article explains the fundamentals of IP addressing, the role of NAT, static and dynamic NAT, NAPT, Easy IP, NAT Server, and NAT ALG, and provides step‑by‑step lab exercises with configuration commands and packet‑capture verification for network engineers.
This article explains how to configure Linux network interfaces, interpret configuration files, set up DNS and hosts, understand routing (static and dynamic), examine IP and MAC header structures, apply CIDR subnetting, differentiate private and public addresses, and choose common virtual networking methods such as bridge, NAT, and host‑only.
This article explains how to configure Linux network settings, describes the contents of key configuration files such as ifcfg, /etc/resolv.conf, and /etc/hosts, and introduces routing concepts, static and dynamic routes, gateways, IP/MAC headers, CIDR, and common virtual networking methods.
This article explains how the OSI network layer moves packets between hosts, covering forwarding, routing algorithms, router architecture, queueing, IPv4 and IPv6 header structures, address classes, and practical migration strategies from IPv4 to IPv6.
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 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.
Despite IPv6 offering vastly larger address space and improved performance, its adoption remains slow due to NAT’s mitigation of IPv4 scarcity, lack of backward compatibility, and complex address management, prompting engineers to rely on dual stacks, tunneling, and resource reclamation strategies to extend IPv4’s lifespan.
This article explains the four primary IP transmission methods—unicast, multicast, broadcast, and anycast—detailing their address ranges, typical use cases, and how they differ in delivering data to one, many, or a selected recipient within a network.
This comprehensive guide explains the fundamentals of IP networking, covering IP address structure, classful and classless addressing, subnetting techniques, public and private address allocation, routing, fragmentation, IPv6 features, and essential protocols such as DNS, ARP, DHCP, NAT, ICMP and IGMP.
This article explains how web load balancing distributes HTTP/HTTPS requests across multiple servers to improve concurrency, availability, and scalability, covering DNS round‑robin, CDN acceleration, IP load balancing, reverse proxy, and layer‑4 techniques with practical insights and diagrams.
This article introduces the OSI model, IP and UDP protocols, explains the structure of IP and UDP packet headers, demonstrates how to create a simple UDP server and client in Python, and shows how to capture and analyze the traffic with Wireshark.
This article uses a playful campus love story to illustrate how messages travel over a network, explaining the role of IP addresses, MAC addresses, broadcast domains, and the ARP protocol in translating an IP to a physical address so data can reach the recipient’s device.
This article explains the structure and fields of IP packets, including version, header length, TOS, total length, ID, flags, fragment offset, TTL, protocol, checksum, source and destination addresses, as well as the formats and key functions of TCP and UDP headers, highlighting their differences.
Understanding website traffic involves distinguishing IP (unique visitors) from PV (page views), interpreting their relationship, and using these metrics to estimate bandwidth needs, with formulas that factor in average page size, peak traffic multiples, and conversion from bytes to bits for accurate capacity planning.
