Snort 3 – Flexible, Modular Intrusion Detection That Speaks Modern Traffic
What is Snort 3
Snort 3 is the latest iteration of one of the most established intrusion detection and prevention systems out there. Originally built as a packet sniffer with signature-based alerting, Snort has evolved into a full-blown modular IDS/IPS engine. This version — Snort 3 — brings real architectural improvements: dynamic pipelines, better scalability, and a Lua-based configuration system that replaces the old config syntax with something far more flexible.
It still does what Snort always did well — inspect traffic, match patterns, fire alerts. But now it does it faster, more cleanly, and with less pain when managing large rule sets or performance tuning.
Snort 3 is maintained by Cisco and under active development. It’s free, fast, and production-ready.
Technical Overview
| Feature | Description |
| Detection Engine | Rule-based, signature-driven, with protocol decoders and preprocessors |
| Modular Pipeline | Packet flow broken into customizable modules |
| Configuration | Lua scripting (more flexible than Snort 2.x static config) |
| Protocol Support | IPv4/6, TCP, UDP, ICMP, DNS, HTTP, TLS, FTP, SMB, and more |
| Logging Formats | Unified2, JSON, PCAP, custom |
| Performance | Multithreaded, supports CPU pinning, optimized for scale |
| Deployment Modes | IDS (inline or passive), IPS, tap, or bridge |
| Rule Source | Snort community + Talos rulesets (subscription optional) |
| License | GPLv2 |
| Website | https://snort.org |
How It Works in Practice
Snort 3 sits in-line or passively on a span port or mirror tap. It ingests packets, decodes protocols, applies rule logic, and spits out alerts, logs, or drops packets — depending on configuration.
Unlike Snort 2.x, the pipeline in v3 is dynamic. You can define how packets flow through detection stages, what gets logged, and how deep inspection should go. Want to skip TLS decryption and focus on DNS? You can. Want to preprocess HTTP headers only under certain conditions? That’s doable.
The Lua config is different from traditional .conf files, but it’s readable once you get used to it — and much more powerful.
Real-World Scenarios
– Dropping known malicious traffic at the gateway based on community rules
– Monitoring east-west traffic inside a corporate LAN via mirrored switch ports
– Alerting on DNS tunneling or malformed TLS handshakes
– Layered detection alongside Suricata or Zeek in a hybrid NIDS setup
– Testing new rules in passive mode before rolling them out in IPS mode
