# conntrack-tools

> set of tools for Linux targeting the conntrack kernel subsystem

**Wikidata**: [Q114589277](https://www.wikidata.org/wiki/Q114589277)  
**Source**: https://4ort.xyz/entity/conntrack-tools

## Summary
conntrack-tools is a set of free software utility tools designed for Linux to interact with the conntrack kernel subsystem. Developed by Pablo Neira Ayuso as part of the Netfilter project, it provides userspace utilities and a daemon to manage and monitor connection tracking systems. The software is licensed under the GNU General Public License version 2.0 or later.

## Key Facts
- **Creator:** Pablo Neira Ayuso, a Spanish computer scientist.
- **License:** GNU General Public License, version 2.0 or later.
- **Component Of:** Netfilter project.
- **Latest Stable Version:** 1.4.8 (released September 29, 2023).
- **Platform:** Linux kernel and Linux-libre.
- **Software Type:** Free software; utility software.
- **Aliases:** conntrack, conntrackd, nfct.
- **Source Repository:** https://git.netfilter.org/conntrack-tools/
- **Official Website:** https://conntrack-tools.netfilter.org/

## FAQs
### Q: What is the primary function of conntrack-tools?
A: It is a set of tools targeting the conntrack kernel subsystem, allowing users to modify conntrack tables and interact with the connection tracking system.

### Q: Who developed conntrack-tools?
A: The tools were created by Pablo Neira Ayuso, a Spanish computer scientist and researcher.

### Q: What are the main components included in conntrack-tools?
A: The set includes `conntrack` (a program to modify conntrack tables), `conntrackd` (a connection tracking daemon), and `nfct` (a tool to interact with the connection tracking system).

## Why It Matters
conntrack-tools plays a critical role in Linux network administration by providing the primary userspace interface to the Netfilter connection tracking system. This subsystem is fundamental to stateful packet inspection, which allows firewalls and network utilities to understand the context of network traffic (such as active connections) rather than just inspecting packets in isolation.

By offering tools to monitor, modify, and synchronize connection tracking states, conntrack-tools enables advanced networking features such as high-availability clusters where connection states must be replicated between nodes. As a part of the wider Netfilter ecosystem, it serves as an essential utility for system administrators managing Linux-based firewalls and routers.

## Notable For
- Being the designated userspace toolset for the Netfilter conntrack kernel subsystem.
- Providing `conntrackd`, a daemon specifically designed for connection tracking synchronization and high availability.
- Inclusion in major Linux distribution repositories, including Debian, Ubuntu, and Gentoo.
- Development by Pablo Neira Ayuso, a prominent figure in the Linux networking community.

## Body

### Components and Functionality
connact-tools is a suite containing multiple specific utilities designed to manage the connection tracking subsystem of the Linux kernel. The software suite includes three primary tools distributed as Debian packages:
*   **conntrack:** A program used to modify the conntrack tables.
*   **conntrackd:** A connection tracking daemon, likely used for synchronization and state replication.
*   **nfct:** A tool specifically designed to interact with the connection tracking system.

### Development and History
The project was created by **Pablo Neira Ayuso**, a Spanish computer scientist, university teacher, and researcher. It is classified as **free software**, allowing users to freely run, study, change, and distribute it. The source code is maintained in a Git repository hosted at `git.netfilter.org`.

The software operates on the **Linux kernel** and is also compatible with **Linux-libre** (a version of the Linux kernel without binary blobs, inception 2008).

### Version History
The project has seen regular updates, with recent stable releases including:
*   **Version 1.4.8:** Released on September 29, 2023.
*   **Version 1.4.7:** Released on October 6, 2022.

### Distribution and Availability
conntrack-tools is widely available across various Linux distributions under specific package names:
*   **Debian:** Source package `conntrack-tools` (active since 2015); binary packages `conntrack`, `conntrackd`, and `nfct`.
*   **Ubuntu:** Packages `conntrack`, `conntrackd`, and `nfct`.
*   **Gentoo:** Package `net-firewall/conntrack-tools`.
*   **Guix:** Package variable `conntrack-tools`.

## References

1. Free Software Directory
2. [conntrack-tools 1.4.7 release. 2022](https://marc.info/?l=netfilter&m=166506855929074&w=2)
3. [conntrack-tools 1.4.8 release. 2023](https://marc.info/?l=netfilter&m=169598613909790&w=2)
4. [Source](https://packages.debian.org/source/bookworm/conntrack-tools)
5. [conntrack-tools 1.4.6](https://guix.gnu.org/en/packages/conntrack-tools-1.4.6/)