The article explains that the entire 127.0.0.0/8 block consists of loopback addresses, shows how addresses like 127.0.0.2 and 127.0.1.1 are reachable, and demonstrates practical uses such as isolating services, simulating clusters, and the special role of 127.0.1.1 on Debian systems.
This article introduces pwru, Cilium's eBPF‑based packet‑tracing tool, explains kernel requirements, shows how to install the pre‑built binary, details command‑line options, and provides practical examples for filtering, output customization, and debugging dropped packets in Linux networking.
This guide explains how to use curl and wget for fetching web content and downloading files, outlines Linux bonding modes for network interface aggregation, and provides step‑by‑step nmcli commands to configure both bonded and regular network interfaces on Linux systems.
This article explains the concepts, mechanisms, and primary uses of SNAT and DNAT in network address translation, and provides step‑by‑step iptables commands and example scenarios for implementing source and destination NAT in Linux environments.
At Netdev 0x19, ByteDance's STE team presented two technical talks: a NUMA‑aware MPTCP flow‑selection strategy that boosts Redis benchmark throughput by up to 30% and cuts tail latency by 6%, and a DPDK‑based user‑space MPTCP stack that halves latency and doubles throughput in data‑center tests.
This article explains the concept of IPVS (IP Virtual Server) as a layer‑4 load balancer, compares ipvs with iptables, details LVS scheduling algorithms, and provides step‑by‑step commands for configuring ipvsadm on both load‑balancer and real‑server nodes, including VIP setup and client testing.
This guide walks through CentOS7 network configuration, explaining interface naming conventions, using NetworkManager tools like nmcli, editing ifcfg files, changing hostnames, renaming interfaces to eth0, adding kernel parameters, and applying changes with service restarts.
This guide walks through CentOS 7 network setup, explaining interface naming conventions, using NetworkManager tools like nmcli and nmtui, editing configuration files, renaming interfaces, adjusting kernel parameters, and applying changes to achieve reliable connectivity.
This comprehensive guide explains Linux Virtual Server (LVS) fundamentals, its general architecture, various load‑balancing modes (NAT, DR, TUN, FULL‑NAT), scheduling algorithms, persistent‑connection options, and provides step‑by‑step ipvsadm commands and scripts for deploying and managing LVS clusters on CentOS 7.
This guide demonstrates how to set up a two‑node Keepalived configuration in dual‑host mode, creating two VRRP instances that act as master and backup to enable seamless VIP address migration between the servers.
This article explains the VXLAN protocol, its advantages over VLAN, the underlying encapsulation process, essential configuration commands, and hands‑on demos using Linux network namespaces, multicast groups, and bridge networking to build scalable overlay networks for cloud environments.
The article introduces xcap, an eBPF‑based next‑generation kernel network packet capture tool that overcomes the limitations of traditional utilities like tcpdump by providing flexible hook points, customizable filtering, and support for diverse network scenarios such as AF_XDP and DPDK, thereby dramatically improving packet‑loss debugging efficiency.
Tcpdump is a classic Linux network packet capture tool that intercepts and displays TCP/IP and other packets, works on most Unix-like systems, and offers powerful command‑line options and filter expressions for selective monitoring, with numerous examples covering interfaces, output formats, and common use cases.
This article explains the advantages of epoll over select for I/O multiplexing in Linux, covering its event-driven design, edge-triggered vs level-triggered modes, core APIs, practical code examples, and performance considerations for high‑concurrency network servers.
This guide presents the most frequently used nmcli commands for displaying, modifying, adding, activating, deactivating, and configuring network interfaces on Linux, including examples for renaming interfaces, setting static IPs, and switching to DHCP mode.
This article outlines five frequent mistakes in C socket programming—ignoring return values, mishandling peer closures, address‑in‑use errors, endianness issues when sending structured data, and false assumptions about TCP framing—while providing concrete code examples and Linux debugging tools to help developers write more reliable network code.
The article explains how the Linux ss command provides comprehensive socket statistics, lists its most useful options, demonstrates performance advantages over netstat with timing examples, and shows how to filter by state, address, or port for efficient system monitoring.
This article explains why TCP and UDP can share the same port number, how multiple TCP processes handle binding, client port reuse, TIME_WAIT implications, and practical solutions like SO_REUSEADDR and tcp_tw_reuse to avoid address‑in‑use errors.
This article explains how Linux servers handle binding to 0.0.0.0, detailing the internal mechanisms of socket binding, listening, and packet processing, with source code analysis to clarify the differences between binding to 0.0.0.0 versus specific IP addresses.
XDP (eXpress Data Path) is a Linux kernel eBPF hook that enables ultra‑fast packet processing at the driver level, offering multiple action codes, three deployment modes, and advantages over DPDK such as lower CPU usage, security, and seamless integration with existing networking tools.
This article explains the internal mechanics of Unix Domain Sockets, shows how they differ from traditional 127.0.0.1 TCP loopback, provides sample code for server and client, and presents benchmark results demonstrating significantly lower latency and higher throughput for local IPC.
This guide shows how to configure one CentOS machine as a NAT gateway using iptables, enabling nine other LAN servers to access the Internet via SNAT or MASQUERADE, with step‑by‑step commands, kernel settings, and client configuration tips.
This guide explains how to use tcpdump’s command‑line options and filter expressions to capture and analyze network packets, covering common flags, syntax for specifying interfaces, hosts, ports, protocols, and practical examples for various scenarios.
This guide explains how to manually configure IP addresses using ifconfig or ip commands, the role of DHCP in dynamic IP allocation, and how PXE leverages DHCP to automate OS installation, covering packet flow, ARP handling, lease renewal, and boot processes.
This guide explains how to view and interpret IP addresses on Windows and Linux, compares net‑tools with iproute2, clarifies IPv4 classful addressing versus CIDR, distinguishes public and private IP ranges, and details MAC addresses and network device flags for reliable networking.
This article explains the principles, advantages, and limitations of various load‑balancing techniques—including HTTP redirection, DNS‑based balancing, reverse‑proxy, LVS‑NAT, LVS‑DR, and LVS‑TUN—while providing practical Linux commands and configuration examples for building scalable systems.
This article explains how to detect whether inbound or outbound packets are being dropped on a Linux system, shows how to use netstat, dropwatch, and perf to pinpoint the cause, and provides step‑by‑step commands and example outputs for debugging packet loss.
This article explains what a SYN Flood DoS attack is, shows how to diagnose it using system logs and netstat, and provides practical mitigation steps such as iptables blocking, F5 load‑balancer filtering, and kernel parameter tuning to protect Linux web servers.
This article explains common load‑balancing solutions, details Linux Virtual Server (LVS) architecture, types, scheduling algorithms, and provides practical ipvsadm command examples for configuring NAT, DR, TUN, and FULLNAT models in a Linux environment.
This guide explains why bandwidth and latency matter for network servers, introduces the qperf tool, shows how to install and run it on Linux, and demonstrates advanced options for testing different message sizes and protocols to uncover performance bottlenecks.
