I’ve built Meds, a high-performance Linux firewall written in Golang, integrating with Netfilter NFQUEUE. It inspects inbound packets in user space and blocks malicious traffic in real time — completely lock-free and built for speed.
Key features:
- NFQUEUE-based packet interception
- Lock-free packet pipeline using atomic ops only
- Per-IP token bucket rate limiting
- TLS SNI & JA3 fingerprint filtering
- Blacklist/whitelist (FireHOL, Spamhaus, Abuse.ch, StevenBlack)
- Prometheus metrics ready
- HTTP API for runtime configuration (add/remove IPs/domains)
Repo: https://github.com/cnaize/meds
Any feedback is very welcome!