DNSCache

Simple and High-Performance DNS Caching resolver

This tool is a simple DNS Cache system that can be used when you have a lot of DNS queries and want to reduce the latency by caching the results. It is implemented in Rust for performance and safety.

I am also developing it to be safe and robust against DNS poisoning attacks, so it includes several verification checks to ensure the integrity of the cached data.

CI Status

Features

• Caches DNS query results for a specified duration.
• Supports both IPv4 and IPv6 addresses.
• Provides a simple command-line interface for querying and managing the cache.
• Uses a HashMap to store the cached results with expiration times.
• Provides Cache auto clean up to remove expired entries.
• Provides stats to check the number of cached entries and cache hit/miss ratio.
• Provides rate-limiter to prevent abuse and protect the upstream DNS server.
• Supports multiple threads to handle concurrent DNS queries efficiently.
• Provides a configuration file to customize the cache behavior and parameters.
• Implements quite a few DNS verification checks to ensure the integrity of the cached data and prevent poisoning attacks.

Supported platforms

• Linux
• macOS
• Windows
• BSD (should build on both FreeBSD and NetBSD)

CPU Architectures supported:

• Tested on ARM64
• Tested on x86_64

Usage

1. Clone the repository and navigate to the project directory:

   git clone https://github.com/pzaino/dnscache
   cd dnscache

2. Build the project using Cargo:

   cargo build --release

3. Edit the configuration file dnscache.toml to set the cache duration and other parameters:

   bind = "127.0.0.1:6363"
   upstream = "8.8.8.8:53"
   threads = 20
   upstream_timeout_secs = 2
   max_cache_ttl_secs = 3600
   cleanup_interval_secs = 120

4. Run the DNS Cache server:

   ./target/release/dnscache

5. You can query the DNS Cache using dig or any DNS client:

   dig @localhost -p 6363 example.com

6. To run system stress test use:

   ./tests/system_test.sh <FQDN>

License

This project is copyright (c) 2026 by Paolo Zaino, all rights reserved. It is licensed under the MPL 2.0 License. See the LICENSE file for more details.

Contributing

Contributions are welcome! If you have any ideas for improvements or want to report a bug, please open an issue or submit a pull request.

Enjoy and happy caching! Paolo :)