Programmable DNS

Overview

This project is a DNS resolver that supports various types of DNS resolution strategies, including basic, static, suffix, and merge resolvers. It allows for flexible configuration of DNS settings through a JSON configuration file, enabling users to define networks, domains, and resolver behaviors.

Features

• Basic Resolver: Resolves DNS queries using a specified DNS server.
• DoT Resolver: Resolves DNS queries using a specified DoT server.
• Static Resolver: Maps domain names to IP addresses based on a static configuration.
• Suffix Resolver: Modifies DNS queries and responses based on specified suffixes.
• Merge Resolver: Combines multiple resolvers and returns the first successful response.

Configuration

The configuration for the DNS resolver is defined in a JSON format. Below is a sample configuration file:

[
  {
    "network": "10.0.0.0/24",
    "domain": "iot.example.com",
    "resolver": {
      "type": "suffix",
      "server": "10.20.0.1:53",
      "oldSuffix": "example.com.",
      "newSuffix": "iot.example.com."
    }
  },
  {
    "domain": "vpn.example.com",
    "network": "10.1.0.0/24",
    "resolver": {
      "type": "static",
      "base": "vpn.example.com",
      "domainsToIPs": {
        "oneiric": "10.1.0.1",
        "focal": "10.1.0.2"
      }
    }
  },
  {
    "domain": "lan.mydomain.org",
    "network": "10.2.0.0/24",
    "resolver": {
      "type": "suffix",
      "server": "10.2.0.254:53",
      "oldSuffix": "lan.",
      "newSuffix": "lan.mydomain.org."
    }
  },
  {
    "network": "192.168.1.0/24",
    "resolver": {
      "type": "merge",
      "resolvers": [
        {
          "type": "basic",
          "server": "10.20.0.1:53"
        },
        {
          "type": "basic",
          "server": "10.21.0.1:53"
        }
      ]
    }
  }
]

Configuration Fields

• network: The CIDR notation of the network.
• domain: The domain name associated with the resolver.
• resolver: An object defining the type of resolver and its specific settings.
  • type: The type of resolver (e.g., basic, static, suffix, merge, dot).
  • server: The DNS server to query (for basic, dot and suffix resolvers).
  • oldSuffix: The suffix to be replaced in DNS queries (for suffix resolvers).
  • newSuffix: The new suffix to be used in DNS queries (for suffix resolvers).
  • base: The base domain for static resolution (for static resolvers).
  • domainsToIPs: A mapping of domain names to IP addresses (for static resolvers).
  • resolvers: An array of resolvers to be merged (for merge resolvers).

Usage

To use this DNS resolver, you need to:

1. Create a JSON configuration file based on the provided sample.