Go DNS Server

A simple DNS server written in Go with a web management interface using Fiber. Perfect for learning DNS fundamentals and local network management.

📖 Detailed Blog Post Explaining DNS & This Project

For a deep dive into DNS fundamentals and the development journey behind this server, read my blog post:
DNS Explained: From Basics to Building My Own DNS Server
(Includes DNS resolution flow, record types, and implementation challenges!)

Features

• 🚀 Basic DNS (A record) resolution
• 🌐 Web-based management API (add/remove records)
• 🔧 In-memory DNS record storage
• 🔄 UDP-based DNS server
• 🔒 Custom port support

Prerequisites

• Go 1.16+
• Admin/root access (for port binding)

Installation

1. Clone the repository:

git clone https://github.com/Denyme24/my-dns-server.git
cd go-dns-server

2. Install dependencies:

go get github.com/gofiber/fiber/v2
go get github.com/miekg/dns

Configuration

1. Edit initial DNS records in main.go:

var dnsRecords = map[string]string{
    "example.com.": "192.0.2.1",
    "test.com.":    "203.0.113.42",
}

2.(Optional) Change ports:

// DNS Server port (default: 9090)
server.Addr = ":9090"

// Web Server port (default: 3000)
app.Listen(":3000")

Usage

1. Start the server :

go run main.go

2. Add DNS records via API:

curl -X POST -H "Content-Type: application/json" \
  -d '{"domain":"mysite.com.","ip":"your_ip"}' \
  http://localhost:3000/records

3. Query DNS records:

dig @127.0.0.1 -p 9090 example.com

Replace 127.0.0.1 with your actual windows host IP

ipconfig | findstr /i "IPv4 Address" 

or for Windows:

nslookup -port=9090 example.com 127.0.0.1

4.View all records:

curl http://localhost:3000/records

Troubleshooting

Connection refused?

• Check firewall rules (allow UDP/TCP on 9090):

New-NetFirewallRule -DisplayName "DNS-Server" -Direction Inbound -Protocol UDP -LocalPort 9090 -Action Allow

• Run as admin/root (required for ports < 1024)
• Verify server is running:

netstat -anu | grep 9090  # Linux
Get-NetUDPEndpoint -LocalPort 9090  # PowerShell

Web interface not working?

• Ensure Fiber server is running on port 3000
• Check for port conflicts:

# Check specific port (e.g., 9090):
Get-NetTCPConnection -LocalPort 9090

Things to keep in mind:

• In-memory storage (records lost on restart)
• Only handles A records