docker-dns

README

Docker DNS Resolver

A lightweight DNS server that resolves Docker container names to their IP addresses, enabling seamless networking between containers and the host.

Features

• Automatic DNS Resolution: Resolve Docker container names with a custom TLD to their respective IP addresses.
• Caching Mechanism: Configurable TTL for DNS cache entries to improve performance.
• Simple Configuration: Minimal setup with command-line options.
• Lightweight and Fast: Built with Go for high performance.

Installation

Prerequisites

• Go (version 1.16 or higher)
• Docker installed and running

Build from Source

git clone https://github.com/medunes/docker-dns.git
cd docker-dns
go build -o dockerdns main.go

Download Binary

Download the latest binary from the Releases page and add it to your $PATH.

Usage

Start the DNS server with default settings:

./dockerdns

By default, the server listens on port 5335 and uses the TLD .docker.

Resolving Container Names

Assuming you have a running container named mycontainer, you can resolve its IP using:

dig @localhost -p 5335 mycontainer.docker

This will return the IP address assigned to mycontainer.

Command-Line Options

Usage of DNS resolver:
  -help
        Display help and usage information
  -port string
        Port on which the DNS server will listen (default "5335")
  -tld string
        Top-level domain for container DNS resolution (default "docker")
  -ttl int
        Time-to-live for DNS cache entries in seconds (default 300)

Examples

• Custom Port and TLD

  ./dockerdns -port 5353 -tld local
  

  Resolves containers like mycontainer.local on port 5353.

• Custom TTL

  ./dockerdns -ttl 600
  

  Sets DNS cache entries to expire after 600 seconds.

Configuration

To integrate the DNS resolver with your system:

1. Update DNS Settings

   Modify your system's DNS settings to include localhost on the port you're using (e.g., 127.0.0.1:5335).

2. Modify /etc/resolv.conf

   Add the following line:

   nameserver 127.0.0.1
   

   Note: Be cautious when modifying system files.

Contributing

Contributions are welcome!

1. Fork the repository.
2. Create a feature branch (git checkout -b feature/YourFeature).
3. Commit your changes (git commit -am 'Add YourFeature').
4. Push to the branch (git push origin feature/YourFeature).
5. Open a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Contact

• Author: medunes
• Email: medunes@protonmail.com

---

Empower your Docker networking with easy-to-use DNS resolution!