Advanced DHCP Server

Lightweight DHCP server written in C# (.NET 10 / C# 14). Designed for clarity and ease of use with a clean, modular structure for configuration, lease management, logging, and server logic.

Overview

This server implements core DHCP operations and provides a straightforward configuration and deployment experience.

Key capabilities:

• DHCP Discover / Offer / Request / Ack / Release / Decline handling
• IP assignment from a configurable pool
• Static MAC-to-IP reservations
• Lease persistence to disk (DHCP_Leases.json)
• Basic IP conflict detection using ICMP ping
• Console and file logging (DHCP_Server.log)

Quick facts

• Language: C# 14.0
• Target: .NET 10
• Default config file: DHCP_Config.json
• Default log file: DHCP_Server.log
• Lease file: DHCP_Leases.json
• UDP server port: 67

Requirements

• .NET 10 SDK
• Elevated privileges to bind to UDP port 67 (Administrator or root) when running locally

Build & Run

From the repository root:

1. Build:

dotnet build

2. Run:

dotnet run --project DHCP-Server

On platforms that require privileges to bind privileged ports, run with appropriate elevation (e.g., sudo on Linux).

Configuration

The server loads configuration from DHCP_Config.json in the working directory. If the file does not exist the server will create a default DHCP_Config.json that you can edit.

Example DHCP_Config.json:

{
  "ServerIp": "192.168.2.1",
  "SubnetMask": "255.255.255.0",
  "Gateway": "192.168.2.1",
  "DnsServer": "192.168.2.1",
  "SecondaryDns": "8.8.8.8",
  "StartIp": "192.168.2.100",
  "EndIp": "192.168.2.200",
  "LeaseDuration": 3600,
  "DomainName": "local.net",
  "NtpServer": "",
  "Reservations": {
    "08-00-27-85-FC-2B": "192.168.2.150"
  }
}

• Reservations keys are MAC addresses in hex format (e.g., 08-00-27-85-FC-2B).

Edit DHCP_Config.json and restart the server to apply changes.

File layout

• Program.cs — entry point
• Config/ConfigLoader.cs — reads and writes configuration
• Config/DhcpConfig.cs — configuration model
• Server/DhcpServer.cs — DHCP server and packet handling
• Leases/LeaseManager.cs — lease persistence and management
• Logging/Logger.cs — console and file logging
• Models/ — models such as DhcpLease and DhcpMessageType

Contributing

Contributions are welcome. Please follow the project style and open a pull request with your changes.