A short description and history of the strongSwan project

strongSwan - Design by Margo Galas <galas (at) solnet (dot) ch

strongSwan is a comprehensive implementation of the Internet Key Exchange (IKE) protocols that allows securing IP traffic in policy- and route-based IPsec scenarios from simple to very complex.

The focus of strongSwan is on


strongSwan was launched in 2005 as a fork of the discontinued FreeS/WAN open source project, integrating the separate X.509 patch that we had been contributing to FreeS/WAN since the year 2000.

Since then a new IKE daemon has been written from scratch in a modern object-oriented coding style so that the current code base does not share code with its ancestor anymore. The modular design of that daemon allows customization through an increasing number of plugins.

Initially, the new daemon only supported IKEv2, while IKEv1 was handled by an extended version of FreeS/WAN's pluto daemon. But because adoption of IKEv2 by other vendors took longer than anticipated, support for IKEv1 was added to the new daemon with strongSwan 5.0 in 2012, which removed pluto and many other legacy components.

For several years the project was maintained by researchers at the University of Applied Sciences Rapperswil, Switzerland, namely, Andreas Steffen, Martin Willi and Tobias Brunner. In June 2022, the intellectual property rights to the strongSwan project were acquired by secunet Security Networks AG.

Current maintainers of the strongSwan project are: