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Encrypted networking for regular people.

Cjdns implements an encrypted IPv6 network using public key cryptography for address allocation and a distributed hash table for routing. This provides near zero-configuration networking without many of the security and robustness issues that regular IPv4 and IPv6 networks have.


To give regular people more power over their communications.

Why are we lacking power and what does that mean? The Internet is in many ways the great equalizer, bringing to everyone the powers once reserved to those wealthy enough to own a radio station or a newspaper. Still the ownership of the actual infrastructure of the net is exclusive for many reasons, mostly because the protocols involved are simply too complex for regular people to use. (For instance, how many isolated wifi networks are in your neighbourhood - why are they not meshed and providing backhaul transit amongst each other in a robust, secure fashion : complexity).

The centralization of power is seen in closure of websites such as wikileaks amid public outcry. Without speaking to the validity of one type of speech or another, it is fair to say that in a truly democratic world, only the most unpopular content such as child abuse, fraud and spam would be censored.

How close is it to complete?

A live testing network exists with roughly 300 active nodes. The software has been tested and is known to work on x86, amd64, ARMv5, ARMv7, MIPS, PowerPC32 and PowerPC64. It is continually tested on Linux systems. While the software itself is stable, the protocols and algorithms are new inventions and we still don't understand how they work in the real world. Please update early and often to give developers the maximum latitude to make tweaks to the protocol and algorithms.

You Can Help!

We are in desperate need for buildbots running on Apple OSX systems. If you would like to donate one, you could mail it or set it up to run all of the time and provide remote shell access. Please join the IRC channel (see the end of this document) and ask about this and other ways you can help. :)


Unlike TOR, I2P and Freenet, cjdns was not designed to provide anonymity against a determined adversary, cjdns does not use sub-optimal routing to bolster anonymity the at cost of performance. Cjdns users do have a measure of anonymity based on the fact that information is only shared between nodes on a need-to-know basis and only those peers who you have manually connected to need to know your IPv4 address.

The most obvious way to get someone's identifying information would be to trace the path through the network between you and them, then demand that each operator along the path reveal the identity of the next. If your directly linked peers have secure computers and are beyond pain then you have very little to worry about.


When you receive a packet of information from the Internet, it seems logical to assume that it was meant for you, that it came from the computer which it says it came from and that nobody else has been reading or modifying it on the way. While many popular software applications are designed around these assumptions, the existing Internet does not guarantee any of them and a number of network security exploits come from the cases where these assumptions break down. Cjdns aims to guarantee these assumptions by using modern cryptography in a non-intrusive way.

Cjdns protects your information from being altered en-route and while you can create arbitrary identities, you cannot impersonate another existing node on the network, making man-in-the-middle attacks unfeasible.


Imagine a network where all the engineer has to do was plug in the wires, the computers instinctively know how to find each other. This is the ultimate goal of cjdns. It is understood that some network engineering will always be necessary but reducing it and simplifying what remains are top priorities.


Cjdns is built around a bold and unproven assumption. It is assumed that a non-hierarchical network can scale. Cjdns uses a technique similar to Distributed Hash Tables in order to spread the load of routing among a number of nodes rather than requiring every node to know the full path to every other node.

How does routing work?

In order to understand how cjdns routing works, it is important to understand how the existing Internet works when you send a packet. At each "intersection in the road" the router reads the address on the packet and decides which turn it should take.

In the cjdns net, a packet goes to a router and the router labels the packet with directions to the router best able to handle it. That is, a router which is physically nearby and has an address numerically close to the destination address of the packet. The directions are added to the packet to allow it to go through a number of routers with minimal handling, a verifiable form of source routing. They just read the label and bounce the packet wherever the next bits in the label tell them to. Routers have a responsibility to "keep in touch" with other routers that are physically close by and numerically near to their address.

The router engine is a modified implementation of the Kademlia DHT design.

What about DNS?

DNS is a complex system to implement and highly complex to implement without central authority. If you would like to offer help with this part, I invite you to come join.

Where did the name cjdns come from?

Cjdns was based on a codebase which was originally intended to handle name resolution (DNS) and so it was a combination of 'cjd' and 'dns'. The project changed direction early on and currently is still lacking DNS resolution but the name stuck. Make up your own acronym for it if you like.

Further Reading & Discussion

Please read the Whitepaper, or at least skim it:

If you are still interested in this project and want to follow it, get in the channel on IRC:

Thank you for your time and interest, Caleb James DeLisle == cjdelisle == cjd

How to install cjdns

These instructions are for Debian / Debian derived distributions. They should be informative enough for user on other distributions - just don't expect them to work verbatim.

0. Install the build tools you will need.

sudo apt-get install cmake git build-essential

1. Retrieve cjdns from GitHub.

Clone the repository from GitHub and change to the source directory:

git clone cjdns
cd cjdns

2. Build.


Look for Build completed successfully, type ./cjdroute to begin setup., then proceed below:


Run cjdroute without options for HELP:


0: Make sure you've got the stuff.

cat /dev/net/tun

If it says: cat: /dev/net/tun: File descriptor in bad state Good!

If it says: cat: /dev/net/tun: No such file or directory

Create it using:

sudo mkdir /dev/net ; sudo mknod /dev/net/tun c 10 200 && sudo chmod 0666 /dev/net/tun

Then cat /dev/net/tun again.

If it says: cat: /dev/net/tun: Permission denied You're probably using a VPS based on the OpenVZ virtualization platform. Ask your provider to enable the TUN/TAP device, this is standard protocol so they should know exactly what you need.

1: Generate a new configuration file.

./cjdroute --genconf >> cjdroute.conf

2: Find a friend.

In order to get into the network you need to meet someone who is also in the network and connect to them. This is required for a number of reasons:

  1. It is a preventative measure against abuse because bad people will be less likely to abuse a system after they were, in an act of human kindness, given access to that system.
  2. This is not intended to overlay The Old Internet, it is intended to replace it. Each connection will in due time be replaced by a wire, a fiber optic cable, or a wireless network connection.
  3. In any case of a disagreement, there will be a "chain of friends" linking the people involved so there will already be a basis for coming to a resolution.

tl;dr Get out and make some human contact once in a while!

You can meet people to peer with in the IRC channel:

NOTE: If you're just interested in setting up a local network between your own computers, this step is not necessary.

3: Fill in your friend's info.

In your cjdroute.conf file, you will see:

        // Nodes to connect to.
            // Add connection credentials here to join the network
            // Ask somebody who is already connected.

After adding their connection credentials, it will look like:

        // Nodes to connect to.
                "password": "thisIsNotARealConnection",
                "publicKey": "thisIsJustForAnExampleDoNotUseThisInYourConfFile.k"

You can add as many connections as you want to your "connectTo" section.

Your own connection credentials will be shown in a JSON comment above in your "authorizedPasswords" section. Do not modify this but if you want to allow someone to connect to you, give it to them.

It looks like this:

    /* These are your connection credentials
       for people connecting to you with your default password.
       adding more passwords for different users is advisable
       so that leaks can be isolated.

            "password": "thisIsNotARealConnectionEither",
            "publicKey": "thisIsAlsoJustForAnExampleDoNotUseThisInYourConfFile.k"
    */ is to be replaced with the IPv4 address which people will use to connect to you from over The Old Internet. contains more details on configuration, including how to peer with other cjdns nodes over ethernet (including wifi).

4: Start it up!

sudo ./cjdroute < cjdroute.conf

If you want to have your logs written to a file:

sudo ./cjdroute < cjdroute.conf > cjdroute.log

To stop cjdns:

sudo killall cjdns

If you are having problems use killall cjdns to return to sanity. Use pgrep cjdns or top to see if it running.

5: Get in IRC

Welcome to the network, you are now a real network administrator. There are responsibilities which come with being a network administrator which include being available in case there is something wrong with your equipment. You can connect to irc via The channel to join is #cjdns and you should stay there so that we are able to reach you.


This starts cjdroute as the root user so cjdroute can configure your system and shed permissions. If you really want to start cjdroute as a non-root user, see Non-Standard Setups below.

Protect your conf file! A lost conf file means you lost your password and connections and anyone who connected to you will nolonger be able to connect. A compromised conf file means that other people can impersonate you on the network.

chmod 400 cjdroute.conf
mkdir /etc/cjdns && cp ./cjdroute.conf /etc/cjdns/

Self-Check Your Network

Once your node is running, you're now a newly minted IPv6 host. Your operating system may automatically reconfigure network services to use this new address. If this is not what you intend, you should check to see that you are not offering more services then you intended to. ;)

1: Obtain IP address.

Use ifconfig -a to find your TUN device's IPv6 address. (Same as above.)

2: Scan for open services.

Run nmap to discover which services are accessible from this address. For example, to scan the address fcf7:75f0:82e3:327c:7112:b9ab:d1f9:bbbe:

nmap -6 -n -r -v -p1-65535 -sT fcf7:75f0:82e3:327c:7112:b9ab:d1f9:bbbe

This should result in an output like the following.

Starting Nmap 5.61TEST2 ( ) at 2011-12-29 20:40 EST
Initiating Connect Scan at 20:40
Scanning fcf7:75f0:82e3:327c:7112:b9ab:d1f9:bbbe [65535 ports]
Completed Connect Scan at 20:40, 4.38s elapsed (65535 total ports)
Nmap scan report for fcf7:75f0:82e3:327c:7112:b9ab:d1f9:bbbe
Host is up (0.00073s latency).
All 65535 scanned ports on fcf7:75f0:82e3:327c:7112:b9ab:d1f9:bbbe are closed

Read data files from: /usr/local/bin/../share/nmap
Nmap done: 1 IP address (1 host up) scanned in 4.60 seconds
    Raw packets sent: 0 (0B) | Rcvd: 0 (0B)

3: If you see anything open, fix it.

Examples for SSH and Samba are below.


Edit /etc/ssh/sshd_config:


^ Replace in the example above with your STATIC IP (or map DHCP via MAC).


Edit /etc/samba/smb.conf:

interfaces = eth0
bind interfaces only = Yes

^ This will cause Samba to not bind to tun0 (or whichever TUN device you are using).

Thats it for now! Got More? Tell us on IRC.

Non-Standard Setups

Most Users Don't Need This

Instructions for building or installing in non-default ways.

Start cjdroute as non-root user.

If you're using an OpenVZ based VPS then you will need to use this as OpenVZ does not permit persistent tunnels.

Create a cjdns user:

sudo useradd cjdns

Create a new TUN device and give the cjdns user authority to access it:

sudo /sbin/ip tuntap add mode tun user cjdns dev cjdroute0

4b-1: Setup the interface manually

Run those commands to prepare your TUN device:

sudo /sbin/ip addr add <your ipv6 address>/8 dev cjdroute0
sudo /sbin/ip link set cjdroute0 up

These commands should be executed as root now every time the system restarts.

Old versions of iproute2

If you see an error when running /sbin/ip, your version of iproute2 might be old.

sudo /sbin/ip tuntap add mode tun user cjdns
Object "tuntap" is unknown, try "ip help".

The fix: for now grab a copy of a newer ip binary and copy it to your home directory. Replacing the system binaries is not likely a good idea.

4b-2: Fire it up!

sudo -u cjdns ./cjdroute < cjdroute.conf

To delete a tunnel, use this command:

sudo /sbin/ip tuntap del mode tun <name of tunnel>

Installing cjdns on OpenIndiana

currently broken by recent changes

In order to install cjdns on an OpenIndiana system, do the following:

sudo pkg set-publisher -p
sudo pkg install runtime/gcc@4.6.2,5.11-0.151.1:20111222T011404Z
sudo pkg install gnu-make
sudo pkg install header-math
sudo pkg install git
sudo pkg install tuntap
git clone git://
cd cjdns

Once it has completed successfully, simply type ./cjdroute and follow the normal instructions

Accessing the cjdns admin interface

When cjdnroute is up and running, an administrative interface will listen on localhost:11234 (this can be changed in the cjdroute.conf configuration file).

You can access this api using the following tools, to get interesting information.

More information about the Admin interface:

python library

cjdns comes with a python library to access the api. For more information, read the readme.

perl library

The perl port of the python api library is maintained by Mikey. For usage instructions, head over to the readme.

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