n3n

n3n is a light VPN software which makes it easy to create virtual networks bypassing intermediate firewalls.

In order to start using n3n, two elements are required:

A supernode: it allows edge nodes to announce and discover other nodes. It must have a port publicly accessible on internet.
edge nodes: the nodes which will be a part of the virtual networks

A virtual network shared between multiple edge nodes in n3n is called a community. A single supernode can relay multiple communities and a single computer can be part of multiple communities at the same time. An encryption key can be used by the edge nodes to encrypt the packets within their community.

n3n tries to establish a direct peer-to-peer connection via udp between the edge nodes when possible. When this is not possible (usually due to special NAT devices), the supernode is also used to relay the packets.

n3n was originally based on an older n2n project and hopes to keep protocol compatiblilty with that.

License

Any new self-contained tools or modules are licensed GPL-2.0-only.
Existing code is licensed GPL-3-only.
There are multiple distinct copyright holders throughout the codebase.
There is no Contributor Licence Agreement and thus there is no single body that can take ownership of the code and/or change the licensing.

Quick Setup

Up-to-date binaries and packages for most distributions are available as part of the latest stable release.

(Since the n3n is protocol compatible with the older n2n, you might be tempted to try and install a package provided by your distribution. At the least Debian has a package called n2n, however it is based on the antique 1.2 version from 2008 and that has not been compatible with n2n for many years, and thus is also not able to interoperate with n3n.)

On host1 run:

$ sudo edge start \
    -c mynetwork \
    -k mysecretpass \
    -a 192.168.100.1 \
    -l supernode.ntop.org:7777

On host2 run:

$ sudo edge start \
    -c mynetwork \
    -k mysecretpass \
    -a 192.168.100.2 \
    -l supernode.ntop.org:7777

Now the two hosts can ping each other. For a longer-term setup, we suggest you use a config file with the settings.

IMPORTANT It is strongly advised to choose a custom community name (the community.name option) and a secret encryption key (the community.key option) in order to prevent other users from connecting to your computer. For the privacy of your data sent and to reduce the server load of supernode.ntop.org, it is also suggested to set up a custom supernode as explained below.

Setting up a Custom Supernode

You can create your own infrastructure by setting up a supernode on a public server (e.g. a VPS). You just need to open a single port (1234 in the example below) on your firewall (usually iptables).

Install the n3n package
Edit /etc/n3n/supernode.conf and add the following:
```
[connection]
bind=1234
```
Start the supernode service with sudo systemctl start supernode
Optionally enable supernode start on boot: sudo systemctl enable supernode

Now the supernode service should be up and running on port 1234. On your edge nodes you can now specify -l your_supernode_ip:1234 to use it. All the edge nodes must use the same supernode (or be part of the same supernode federation)

Manual Compilation

On Linux, compilation from source is straight forward:

./autogen.sh
./configure
make

# optionally install
make install

For compiling under Windows or MacOS, enabling various optimizations and generally other options available to build, please check the Building documentation

The project main branch is used for development work and reflects the code that is expected to go into the next release - it is thus possible that it has not been fully tested and may contain bugs or partially implemented features. If you wish to help with testing or to implement a new feature, you are encouraged to compile from main. Feedback in the issues tracker is appreciated.

Once a release is stable, it will be tagged - and if a bug fix needs to be backported to a stable release a branch will be created for the patch releases containing these backported patches.

Security Considerations

When payload encryption is enabled (provide a key using community.key), the supernode will not be able to decrypt the traffic exchanged between two edge nodes but it will know that edge A is talking with edge B.

There are multiple encryption options to choose from. Please have a look at Crypto description for a quick comparison chart to help make a choice. n3n edge nodes use AES encryption by default. Other ciphers can be chosen using the community.cipher option.

A benchmark of the encryption methods is available when compiled from source with tools/n3n-benchmark.

The header which contains some metadata like the virtual MAC address of the edge nodes, their IP address, their real hostname and the community name optionally can be encrypted applying the community.header_encryption=true option to the edges.

Advanced Configuration

More information about communities, support for multiple supernodes, routing, traffic restrictions and on how to run an edge as a service is available in the more detailed documentation.

Contribution

You can contribute to n3n in various ways:

Update an open issue or create a new one with detailed information
Propose new features
Improve the documentation
Provide pull requests with enhancements

For details about the internals of n3n check out the Hacking guide.

docyc / n3n

n3n