MyDNS

MyDNS is a DNS server application written in Go. It is designed to be simple, efficient, and easy to use.

Features

• Lightweight and fast
• Easy to configure
• Basic DNS functionalities: query and block domains
• Load balancing

Requirements

• Go 1.16 or later
• Redis 6.0 or later (optional)

Installation

1. Clone the repository:

   git clone https://github.com/darwineee/MyDNS.git
   cd mydns

2. Build the application:

   make build

   The executable file will be generated in the bin directory.

Usage

1. Create a configuration file named config.yaml in the root directory of the application. Available options are demonstrated in source code config.yaml file as default values. If you want to use the default values, you can skip this step.

2. Create blacklist and known_hosts files in the root directory of the application. The blacklist file contains a list of domain names only, whereas known_hosts contains a map of domain names and IP addresses. Put each entry one per line. The blacklist file can be used to block access to certain domains, while the known_hosts file can be used to resolve them. Both files are optional. Skip this step if you don't need them.

3. Run the application:

   make run

4. The application will start and listen for DNS queries on port 2053 using UDP by default. You can change these settings in the configuration file. However, in practice, you don't need to change them.

5. To stop the application, press Ctrl + C or type the command stop. More commands will be supported in the future.

6. This application uses the system resolver. You can add more foreign name servers to the OS's resolver configuration file. For example, it is /etc/resolv.conf on Unix-like systems.

Development

This application implements the RFC-1035 specification.

                           Local Host          |    Foreign
                                               |
+---------+               +----------+         |  +--------+
|         | user queries  |          |queries  |  |        |
|  User   |-------------->|          |---------|->| Foreign|
| Program |               |  MyDNS   |         |  |  Name  |
|         |<--------------|          |<--------|--| Server |
|         | user responses|          |responses|  |        |
+---------+               +----------+         |  +--------+
                            |     A            |
            cache additions |     | references |
                            V     |            |
                          +----------+         |
                          |  Redis   |         |
                          +----------+         |

Redis is used as a caching layer.

To handle high QPS, I implemented an event loop to handle incoming DNS queries concurrently. The event loop is as simple as below: