blockchecks

Asynchronous DPI (Deep Packet Inspection) strategy testing framework for nfqws2 / zapret2.

It runs thousands of desync strategies against target domains inside isolated network namespaces, using a browser-grade TLS fingerprint (JA4 via curl_cffi), and reports which combinations actually work on a given network. Results are stored in SQLite and can be exported to ready-to-use nfqws2 configuration files for Keenetic / OpenWrt / Linux routers.

Features

• Fast: ~1 test/sec (33× faster than the reference blockcheck.sh) via asyncio + a reused netns pool.
• Accurate: browser-grade JA4 TLS fingerprint (Chrome BoringSSL), content validation, DPI fake-detection.
• TCP + UDP: TCP strategy families, HTTP :80, QUIC/HTTP3, and Discord Voice UDP endpoint discovery (STUN + IP Discovery).
• Resilient: checkpoint/resume, SQLite state, adaptive priority queue.
• Tooling: static strategy validator (offline, 9+ rules), custom Lua registry, MCP server for LLM agents.
• Portable: installs on x86_64, arm64 and armv7l (Raspberry Pi 2+) without compiling native dependencies.

Requirements

• Linux with root (needed for network namespaces + iptables)
• Python 3.10+
• nfqws2 / zapret2 (auto-fetched on first run)

Quick start

pip install blockchecks

# First scan — ~30 strategies against discord.com
sudo bs scan -d discord.com --generate --parallel 4

# Resume after interruption (checkpoint/resume)
sudo bs scan -d discord.com --generate --resume

Export a router config

# default: ~/.local/share/blockcheckS/export/nfqws2_<ts>.conf (+ raw, user.list)
bc-nfconf --db logs/run.db --out-dir /path/to/out

# optional: add an IP filter from the DNS cache (no DNS needed on the router)
bc-nfconf --db logs/run.db --out-dir /path/to/out --ipset

Documentation

• User guide
• Architecture
• MCP server
• Changelog

License

MIT — see LICENSE.

Disclaimer

This software is an open-source analytical tool for educational, academic and network-research purposes, intended for network administrators and systems engineers to study DPI behaviors. Use entirely at your own risk.