Ultra-Fast DNS Caching Server (Go)

This project is a high-performance DNS caching server written in Go. Its primary goal is microsecond-level response latency on cache hits. It supports both A and AAAA record types and uses an in-memory LRU cache. It forwards uncached queries to a trusted upstream DNS resolver.

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Features

• ⚡ Microsecond-level cache latency
• 📦 LRU cache with TTL-aware expiration
• 🔀 Supports A and AAAA DNS queries
• 🌐 Upstream fallback to 1.1.1.1 (Cloudflare)
• 🛠️ Deployable via systemd

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Upstream DNS Provider

• Provider: Cloudflare
• Address: 1.1.1.1
• Port: 53

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Performance Benchmark

Tool Used

• Tool: dnsperf
• Command:

dnsperf -s 127.0.0.1 -d formatted_domains.txt -l 20

Result:

Queries sent:         2,611,659
Queries completed:    2,611,659
Queries lost:         0
Response codes:       NOERROR 100%
QPS:                  130,578
Average latency:      740 µs
Latency min:          23 µs
Latency max:          530 ms

This benchmark was conducted under ideal cache-hit conditions with optimized network stack settings on a local machine.

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How to Build

go build -o dnscache main.go

How to Run

./dnscache

Listens on UDP port 5523.

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Systemd Service Setup

1. Install the binary

sudo cp dnscache /usr/bin/
sudo chmod +x /usr/bin/dnscache

2. Create a service file

# /etc/systemd/system/dnscache.service
[Unit]
Description=Ultra-fast DNS caching server written in Go
After=network.target

[Service]
ExecStart=/usr/bin/dnscache
Restart=on-failure
User=nobody
Group=nogroup

[Install]
WantedBy=multi-user.target

3. Enable and Start

sudo systemctl daemon-reexec
sudo systemctl daemon-reload
sudo systemctl enable dnscache
sudo systemctl start dnscache

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Notes

• Only queries with A and AAAA types are currently cached.
• Uncached queries are resolved via Cloudflare (1.1.1.1:53).
• Cache TTL is derived from the lowest TTL of all Answer RRs.
• Default cache size is 1024 entries (LRU).