# appneta/tcpreplay

Edit and replay captured network traffic at arbitrary speeds — a suite of pcap tools for *NIX and Windows.

Repository: https://github.com/appneta/tcpreplay
Canonical: https://ross.abutalabs.com/products/tcpreplay
Homepage: https://tcpreplay.appneta.com
Language: C
License: GPL-3.0
License Family: copyleft
Topics: tcpreplay, pcap, netmap, c, replays-pcap-files, flow, traffic, netflow, performance, performance-testing, packet-generator
Last push: 2026-08-15T16:15:36+00:00

## Health v2 (maintenance only)
Score: 98/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 97, release rhythm 98, longevity 100
- inputs: {"age_days": 4670, "days_push": 18, "days_rel": 19, "gap_med": 3, "n_releases_24m": 6}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1344, forks 295 (observed 2026-08-28T04:04:27.087973+00:00)

## What it is
Tcpreplay is a suite of GPLv3 command-line utilities for editing and replaying captured network traffic (pcap files) back onto the network at speeds from a trickle to full wire rate. It includes tools for classifying client/server traffic, rewriting Layer 2-4 headers, and replaying captures through firewalls, IDS/IPS, and NetFlow appliances for testing.

## Use cases
- replay a pcap capture onto a test network at original timing or line rate
- rewrite MAC/IP addresses and ports in a capture to retarget it at a lab device
- test firewall, IDS/IPS, or NetFlow appliances with realistic repeatable traffic
- split a capture into client and server sides for two-NIC in-line testing
- replay a captured TCP session against a live server
- measure flows-per-second performance of flow-based network appliances

## When to choose
- you need to push real captured packets back onto the wire for device testing
- you want to tune IDS/IPS or NetFlow appliances against realistic traffic at controlled rates
- you need to rewrite packet headers to retarget captures at a lab environment
- you need high-rate packet injection with netmap, AF_XDP, or io_uring fast paths

## When to avoid
- you need to synthesize new traffic rather than replay existing captures
- you need protocol-aware TCP session synchronization against arbitrary servers (only tcpliveplay handles a single TCP stream)
- you want a GUI-based traffic generator

## Facets
- artifact type: cli-tool
- maturity: active
- function: networking, benchmarking, security, developer-tools
- domain: networking, security, performance, developer-tools
- platform: windows, bsd, cli
- tags: pcap, packet-replay, traffic-generation, netflow, ids-testing, firewall-testing, packet-crafting, netmap, af-xdp, linux, macos

## Member repositories
- appneta/tcpreplay (main) score 98

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:27.087973+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T04:42:49.228456+00:00, confidence not recorded.
  - readme: https://github.com/appneta/tcpreplay (fetched 2026-08-28T04:04:27.087973+00:00, sha 22481e2322fc)
  - homepage: https://tcpreplay.appneta.com (fetched 2026-08-29T12:02:10.680106+00:00, sha cef9d12926f9)
  - site_page: https://tcpreplay.appneta.com/getting-started (fetched 2026-08-29T12:02:10.689702+00:00, sha a204d4c891e7)
  - site_page: https://tcpreplay.appneta.com/about (fetched 2026-08-29T12:02:10.694356+00:00, sha 727d1121fc21)
  - site_page: https://tcpreplay.appneta.com/getting-started/installation (fetched 2026-08-29T12:02:10.695938+00:00, sha e8226df9fea3)
  - site_page: https://tcpreplay.appneta.com/getting-started/quickstart (fetched 2026-08-29T12:02:10.697633+00:00, sha c67d8a0340f5)
  - site_page: https://tcpreplay.appneta.com/about/history (fetched 2026-08-29T12:02:10.699441+00:00, sha 7a49191747be)
  - site_page: https://tcpreplay.appneta.com/about/support (fetched 2026-08-29T12:02:10.701042+00:00, sha 2372840fc484)
  - site_page: https://tcpreplay.appneta.com/faq (fetched 2026-08-29T12:02:10.691703+00:00, sha 3c6d19a3b565)
- Data as of 2026-08-30T08:39:29.467469+00:00.