codecopy / tinc

a VPN daemon

tinc

This is the README file for tinc version 1.1pre18. Installation instructions may be found in the INSTALL file.

tinc is Copyright © 1998-2021 Ivo Timmermans, Guus Sliepen [email protected], and others.

For a complete list of authors see the AUTHORS file.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. See the file COPYING for more details.

Nightly builds

You can download pre-built binary packages for multiple Linux distributions and Windows here:

• development version
• latest release

Note that these packages have not been heavily tested and are not officialy supported by the project. Use them at your own risk. You are advised to use tinc shipped by your distribution, or build from source.

This is a pre-release

Please note that this is NOT a stable release. Until version 1.1.0 is released, please use one of the 1.0.x versions if you need a stable version of tinc.

Although tinc 1.1 will be protocol compatible with tinc 1.0.x, the functionality of the tinc program may still change, and the control socket protocol is not fixed yet.

Security statement

This version uses an experimental and unfinished cryptographic protocol. Use it at your own risk.

When connecting to nodes that use the legacy protocol used in tinc 1.0, be aware that any security issues in tinc 1.0 will apply to tinc 1.1 as well. On September 6th, 2018, Michael Yonly contacted us and provided proof-of-concept code that allowed a remote attacker to create an authenticated, one-way connection with a node using the legacy protocol, and also that there was a possibility for a man-in-the-middle to force UDP packets from a node to be sent in plaintext. The first issue was trivial to exploit on tinc versions prior to 1.0.30, but the changes in 1.0.30 to mitigate the Sweet32 attack made this weakness much harder to exploit. These issues have been fixed in tinc 1.0.35 and tinc 1.1pre17. The new protocol in the tinc 1.1 branch is not susceptible to these issues. However, be aware that SPTPS is only used between nodes running tinc 1.1pre* or later, and in a VPN with nodes running different versions, the security might only be as good as that of the oldest version.

Compatibility

Version 1.1pre18 is compatible with 1.0pre8, 1.0 and later, but not with older versions of tinc.

When the ExperimentalProtocol option is used, tinc is still compatible with 1.0.X, 1.1pre11 and later, but not with any version between 1.1pre1 and 1.1pre10.

Requirements

In order to compile tinc, you will need a GNU C compiler environment. Please ensure you have the latest stable versions of all the required libraries:

• LibreSSL (http://www.libressl.org/) or OpenSSL (https://openssl.org/) version 1.1.0 or later.

The following libraries are used by default, but can be disabled if necessary:

• zlib (https://zlib.net/)
• LZO (https://www.oberhumer.com/opensource/lzo/)
• ncurses (https://invisible-island.net/ncurses/)
• readline (https://cnswww.cns.cwru.edu/php/chet/readline/rltop.html)

Features

Tinc is a peer-to-peer VPN daemon that supports VPNs with an arbitrary number of nodes. Instead of configuring tunnels, you give tinc the location and public key of a few nodes in the VPN. After making the initial connections to those nodes, tinc will learn about all other nodes on the VPN, and will make connections automatically. When direct connections are not possible, data will be forwarded by intermediate nodes.

Tinc 1.1 support two protocols. The first is a legacy protocol that provides backwards compatibility with tinc 1.0 nodes, and which by default uses 2048 bit RSA keys for authentication, and encrypts traffic using AES256 in CBC mode and HMAC-SHA256. The second is a new protocol which uses Curve25519 keys for authentication, and encrypts traffic using Chacha20-Poly1305, and provides forward secrecy.

Tinc fully supports IPv6.

Tinc can operate in several routing modes. In the default mode, "router", every node is associated with one or more IPv4 and/or IPv6 Subnets. The other two modes, "switch" and "hub", let the tinc daemons work together to form a virtual Ethernet network switch or hub.

Normally, when started tinc will detach and run in the background. In a native Windows environment this means tinc will install itself as a service, which will restart after reboots. To prevent tinc from detaching or running as a service, use the -D option.

The status of the VPN can be queried using the "tinc" command, which connects to a running tinc daemon via a control connection. The same tool also makes it easy to start and stop tinc, and to change its configuration.