Highly Available Enterprise Network Simulation 🌐

This repository contains a comprehensive Cisco Packet Tracer lab simulating a secure, highly available small enterprise network. It demonstrates advanced routing, switching, and core network services required for modern business environments.

📌 Project Topology

![Network Topology]

🎯 Objective

To design and configure a multi-department network (Admin, HR, and IT) with secure internet access, redundant core routing, and centralized server management.

🛠️ Technologies & Protocols Implemented

This lab showcases practical configuration of the following technologies:

• Subnetting (VLSM): Efficient IP allocation from a 192.168.10.0/24 block.
• Layer 2 Switching: VLAN creation (10, 20, 30), 802.1Q Trunking, and Access ports.
• Spanning Tree Protocol: Rapid PVST+ with Primary and Secondary Root Bridge elections.
• Link Aggregation: Layer 2 EtherChannel (LACP) between core switches.
• First Hop Redundancy: HSRP (Hot Standby Router Protocol) for gateway failover.
• Inter-VLAN Routing: Switch Virtual Interfaces (SVIs) on Multilayer Switches.
• Network Address Translation: NAT Overload (PAT) for internet connectivity.
• Core Services: Centralized DHCP pools with excluded addresses and helper-addresses.
• Server Management: Internal DNS resolution, NTP time synchronization, and Syslog monitoring.
• Device Security: Encrypted passwords (secret), localized usernames, and MOTD warning banners.

🏢 Network Architecture

• Edge/Perimeter: A single Cisco ISR router handling NAT and outside routing.
• Core/Distribution: Two Cisco 3560 Multilayer Switches acting as Active/Standby HSRP gateways and Rapid-PVST+ Root Bridges.
• Access Layer: Three dedicated Cisco 2960 switches for Admin, HR, and IT departments with portfast enabled.
• Services: An internal IT server providing DNS, Syslog, and NTP, alongside an external ISP server hosting a custom HTML webpage for connectivity testing.

🚀 How to Run the Simulation

1. Clone this repository to your local machine.
2. Open the Small_Company_Network.pkt file using Cisco Packet Tracer.
3. Test Failover: Run a continuous ping (ping 8.8.8.8 -t) from any PC and delete the physical cable between MLS1 and R1 to observe HSRP seamless failover.
4. Test Services: Open a PC web browser and navigate to google.com to verify DNS resolution and NAT routing.

📂 Repository Structure

• /Configurations - Contains the raw IOS CLI configuration files for every router and switch.
• Small_Company_Network.pkt - The Packet Tracer lab file.
• Network_Topology.png - Visual diagram of the network architecture.