This guide demonstrates how to configure routers, firewalls, NAT, and IPSec policies to establish a site‑to‑site VPN between a headquarters and branch office when both use NAT devices, enabling mutual access and internet connectivity.
This tutorial walks through designing a network topology, configuring static and DHCP IPs, disabling the default firewall, installing and initializing iptables and DHCP services, setting up NAT and port forwarding, and persisting the configuration on a Linux server.
This guide walks through expanding an e‑commerce website from 1,000 QPS to 3,000 QPS by deploying an LVS load‑balancing cluster, covering NAT and DR modes, IPVS configuration, kernel tuning, persistent connections, and SSL termination with step‑by‑step commands and diagrams.
This comprehensive guide explains the fundamentals of iptables, covering its architecture, chain and table concepts, rule syntax, matching modules, actions, and practical examples for filtering, NAT, and port forwarding, enabling readers to configure Linux firewalls effectively in virtual or container environments.
This article introduces Session Border Controllers (SBC), outlines three typical deployment scenarios, and shares detailed practical experiences—including architecture, implementation steps, and common pitfalls—of building software‑based SBC solutions such as VAG, VIG, and VTG for VoIP services.
This comprehensive tutorial explains the fundamentals of Linux Virtual Server (LVS), its architecture, scheduling algorithms, and detailed step‑by‑step configurations for NAT, DR, and Tun modes, including scripts, iptables rules, and keepalived HA integration, with testing procedures and reference links.
This guide details how to configure a Huawei AR2220 router with a single WAN port to enable PPPoE dial‑up, set up default routing, NAT, and DHCP services so that internal LAN users can access the Internet using the specified credentials.
This guide demonstrates how to configure ACL and NAT on Huawei AR series routers to block internal hosts from accessing external web interfaces and to restrict web management access to specific subnets, including step‑by‑step command examples and verification procedures.
This guide walks through setting up a LAN with a static‑IP server, configuring iptables firewall rules, enabling NAT and port forwarding, and deploying a DHCP server on CentOS, complete with sample configuration files and command‑line steps.
This document provides a comprehensive set of Huawei router configuration commands covering system settings, SNMP, time, portal loading, security policies, ACL rules, user authentication, firewall zones, interface definitions, IP addressing, NAT, static routes, and user interface configurations.
This article details a troubleshooting case on an AR2240 device where policy routing and NAT redirection prevented an internal host from reaching a server via a public IP, explains the root cause of missing ACL rules, and provides the configuration changes that resolved the issue.
This article explains how to combine source NAT and NAT Server to implement bidirectional NAT on Huawei firewalls, classifies inter‑zone and intra‑zone NAT types, provides detailed configuration examples, and discusses the benefits and packet flow of each scenario.
This article explains how to split a NAT server across two ISPs using zone or no‑reverse parameters, addresses source‑return path issues with redirect‑reverse or reverse‑route commands, and shows how adding VRRP resolves ARP conflicts and intermittent connectivity in dual‑firewall deployments.
This guide explains how to set up NAT server and NAT outbound on a Huawei router so that internal users can access a server via the router's WAN IP on port 80 and external users can reach the same server using port 8089, including required ACL and interface configurations.
This guide details step‑by‑step configuration of ACL and static NAT on the web interface for same‑subnet and different‑subnet scenarios, explains a VPN routing problem on an AR2200 LAC, identifies the NAT‑related root cause, and provides the corrective actions.
This article explains why a denied PC can still access the Internet on an AR device due to ACL rule ordering and missing external‑interface application, and provides step‑by‑step configuration changes, including revised ACL statements and the required traffic‑filter command.
This guide explains how to configure a Huawei router to automatically differentiate China Telecom and China Unicom traffic, route each to its respective ISP, and enable seamless failover to the Telecom line if the Unicom link fails, using NAT, ACLs, and policy routing.
This article explains why accessing an internal web server via its public NAT address fails, analyzes the current Huawei router configuration, and provides step‑by‑step NAT and ACL adjustments along with alternative access methods to resolve the issue.
This article explains the architecture of Linux Virtual Server (LVS) load balancers, detailing the roles of the Director server, Real servers, shared storage, and the three primary IPVS scheduling modes—DR, NAT/FULL NAT, and TUN—including their mechanisms, advantages, and configuration considerations.
This article provides a comprehensive technical guide to Linux Virtual Server (LVS) architecture, covering the load‑balancer layer, server array, shared storage, and detailed explanations of DR, NAT, Full NAT, and IP‑tunnel modes along with their scheduling algorithms and practical deployment considerations.
This article explains how DNS hijacking and dynamic NAT can cause cross‑operator network slowdowns, illustrates real‑world examples, and presents practical solutions such as httpDNS and flow‑302 redirection to improve connectivity and user experience.
LVS (Linux Virtual Server) is a core kernel module for load balancing that forwards client requests to backend servers using three main mechanisms—Network Address Translation (NAT), IP tunneling (TUN), and Direct Routing (DR)—each with distinct packet handling and performance characteristics.
This article provides a step‑by‑step configuration example for a router, detailing external and internal interface settings, NAT server and static NAT rules, outbound NAT policies, and corresponding ACLs to control traffic between multiple subnets.
This guide provides detailed commands to configure a switch for user access VLANs, set up a firewall as both a layer‑3 and layer‑2 device with VLAN interfaces, DHCP/DNS, security zones, static routing, and NAT to enable internal users to reach external networks.
This article discusses whether PC1 can successfully access PC2’s web service when outbound traffic passes through a NAT router but the return packets bypass the router via a core switch, examining potential TCP connection issues caused by asymmetric routing and providing relevant ACL and NAT configuration examples.
This article explains how Linux hosts use TAP/TUN to simulate virtual switches and layer‑3 devices, detailing four common single‑host virtual network models—NAT, routing, bridge, and isolation—and how they enable communication between virtual machines and external networks.
This guide explains how VMware Workstation simulates physical network devices, sets up virtual NICs and switches, and uses DHCP and NAT services to enable guest VMs to communicate internally, bridge to the host network, or access the Internet.
This article explains how to configure ACLs and NAT on a campus router, including static global NAT, outbound NAT with Easy‑IP, loopback interface setup, and verification steps to ensure internal users can reach the server via the public IP address.
This guide demonstrates how to configure NAT with an ACL, set up internal and external interface IP addresses, define a default static route, and create an ACL‑based traffic policy to block specific internal hosts from accessing a given external IP address.
This guide details step‑by‑step router configuration to assign interface IPs, set up VLANs, create NAT server mappings for web and FTP services, define a default static route, and enable FTP NAT ALG so external users can reach internal servers securely.
This guide explains the fundamentals of Linux Virtual Server (LVS), covering cluster concepts, types, scheduling algorithms, ipvsadm commands, and detailed configuration examples for NAT and DR models, culminating in a complete web‑server load‑balancing deployment with Discuz on CentOS.
This guide outlines how to diagnose and resolve slow internet on AR routers by checking CPU usage, TCP MSS settings, traffic load, uplink bandwidth, link negotiation, NAT resource limits, and potential network virus infections, providing specific commands and configuration steps for each issue.
This article provides a step‑by‑step network configuration example showing how to set external and internal IP addresses, enable DHCP, define static routes, create ACL rules, and configure NAT outbound translation on a router.
This comprehensive guide explains Linux firewall concepts, the evolution and operation of iptables, rule chains, policies, command syntax, matching criteria, state tracking, NAT/DNAT techniques, and practical exercises, providing readers with the knowledge to configure and manage secure network access effectively.
