tcpreplay ☆

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Description:
Replay saved tcpdump files at arbitrary speeds

Type: Formula | Tracked Since: Dec 28, 2025

Links: Homepage | formulae.brew.sh

Category: Networking

Tags: networking packet-capture testing replay security

Install: brew install tcpreplay

About:
Tcpreplay is a suite of tools for replaying previously captured network traffic from tcpdump or similar packet capture utilities. It allows users to re-inject traffic into a network at different speeds and under various network conditions. This enables detailed testing and analysis of network devices, intrusion detection systems, and security applications in a controlled, repeatable manner.

Key Features:

High-speed packet replay with precise timing control
Supports editing and manipulating packet headers (e.g., source/destination IP)
Can cache packets to disk for faster, consistent replay performance
Integrates with tcprewrite for on-the-fly packet modification

Use Cases:

Testing firewall and IDS/IPS rule sets against real attack traffic
Benchmarking network device performance under load
Validating application behavior with specific network conditions

Alternatives:

ostinato – Ostinato provides a GUI for packet generation and replay, whereas tcpreplay is command-line focused and optimized for replaying existing capture files.
scapy – Scapy is a powerful Python library for packet manipulation that can be scripted for replay, but tcpreplay offers a more specialized and performant solution for bulk replay of large capture files.

Version History

Detected	Version	Rev	Change	Commit
Sep 12, 2025 3:13am		0	VERSION_BUMP	9a21944b