Tool

Scapy

Script packet dissection, construction, request/reply matching and capture-file analysis in Python. Custom packet fields and layer bindings let analysts encode understood wire formats and investigate protocol behavior.

Targets: Protocol
Category: Protocol analysis tools
Relationship: Foundation tool
Sources reviewed: 2026-10-17

Requirements & limits

Reviewed stable release: 2.8.0, published 2026-10-02. Its package metadata requires Python >=3.7,<4; upstream says the 2.8 major version is the last to support Python 3.7 and 3.8. Use release-matched documentation rather than older cached version pages.
Linux, macOS and BSD have documented platform support; Windows requires Npcap. Live capture or packet transmission needs suitable interfaces and privileges. Offline capture analysis is a separate workflow, and libpcap requirements vary by platform and feature.
Optional features have additional dependencies, such as cryptography for cryptographic functionality and plotting tools for visual reports. Unknown formats require suitable custom Packet/Field definitions and bindings; dissection does not automatically infer complete protocol semantics or peer implementations.
GPL-2.0-only in the reviewed package metadata, with dependency and capture-driver licenses separate. The 2.8.0 release notes describe security fixes.