tcpdump
What it is
tcpdump is a network monitoring and data acquisition tool that captures traffic through libpcap, an interface for user-level packet capture. It provides command-line tools and supports PCAP. The project lists AIX, BSD systems, GNU/Linux, macOS, Solaris, QNX, and Windows among the systems where it compiles and works; native packages or ports are available on many systems. The software is free, and its license permits redistribution and use in source and binary forms under stated conditions. Building it requires libpcap and a C99-compliant compiler. Windows builds also require WinPcap or Npcap and Visual Studio with CMake. Whether you can capture traffic depends on your operating system and its configuration. The project warns that capture permissions may allow access to network traffic, including passwords. Native packages can sometimes lag behind; a newer snapshot can be compiled from source.
For and against
For
- Free software with source code available.
- Command-line tools and PCAP support.
- Works across a broad range of listed systems.
- Can capture from local or remote sources.
Against
- Building requires libpcap and a C99 compiler.
- Windows builds require additional tools.
- Capture permissions depend on operating system configuration.
- Native packages may lag behind.
The verdict
tcpdump offers command-line packet capture and network monitoring across many systems. Check build requirements and capture permissions before using it, especially where network traffic may contain passwords.
Who it suits
It suits users who need command-line network monitoring and packet capture. Users should consider their system's capture permissions and the sensitivity of traffic they may be able to capture.
Plans and prices
tcpdump
BSD-licensed software · capture permission depends on operating system and configuration
Read 3 Oct 2026 · github.com
On the record
- Build requirement
- Building tcpdump requires libpcap and a C99-compliant compiler.github.com · read 3 Oct 2026
- Capture library
- tcpdump uses libpcap, a system-independent interface for user-level packet capture.github.com · read 3 Oct 2026
- Capture permissions
- The installation notes say whether a user can capture traffic depends on the operating system and its configuration.github.com · read 3 Oct 2026
- Distribution
- The project provides source code through its public Git repository and describes native operating system packages or ports as available on many systems.github.com · read 3 Oct 2026
- Intended users
- The README describes tcpdump as a tool for network monitoring and data acquisition, and notes its origin in research on TCP and Internet gateway performance.github.com · read 3 Oct 2026
- License
- The project license permits redistribution and use in source and binary forms subject to its listed conditions.github.com · read 3 Oct 2026
- Package versions
- The project notes that native packages are sometimes a few versions behind and that a newer snapshot can be compiled from source.github.com · read 3 Oct 2026
- Purpose
- tcpdump is a tool for network monitoring and data acquisition.github.com · read 3 Oct 2026
- Security consideration
- The installation notes caution that users able to capture traffic may capture network traffic including passwords.github.com · read 3 Oct 2026
- Security reporting
- The project asks users to report security issues by email to [email protected].github.com · read 3 Oct 2026
- Support and contributions
- The project directs users to its source tree contribution guidelines for bugs, patches, feature requests, and general feedback.github.com · read 3 Oct 2026
- Supported systems
- The project lists AIX, several BSD systems, GNU/Linux, macOS, Solaris, QNX, and Windows among platforms on which tcpdump compiles and works.github.com · read 3 Oct 2026
- Windows requirement
- The project says Windows builds require WinPcap or Npcap and Visual Studio with CMake.github.com · read 3 Oct 2026
