You want to join dn42, but you don't know where to start. This guide gives general guidelines about dn42 and routing in general, but it assumes that you are knowledgeable with routing.


  • you have at least one router running 24/7. Any Linux or BSD box can be turned into a router. If your home router runs OpenWRT, you might consider using it for dn42.
  • your router is able to establish network tunnels over the Internet (Wireguard, GRE, OpenVPN, IPSec, Tinc…). Beware, your network operator might filter this kind of traffic, e.g. in schools or universities.
  • you are generally knowledgeable with networking and routing (i.e. you've heard about BGP, IGP, forwarding, and you're willing to configure a BGP router such as FRR or Bird)


Don't worry, it's not as tedious as registering with a RIR ;)

Subscribe to the mailing list

This is important, as it allows to stay up-to-date on best practices, new services, security issues…

See Contact to subscribe.

Fill in the registry

You must create several objects in the DN42 registry:

The registry is a git repository, objects are created by forking the main repository, making your changes and then submitting a pull request for review. There are detailed instructions in the registry README how to do this. See also the the generic git documentation git documentation and guides on github for how to use git to work with remote repositories.

While filling out the objects in the DN42 registry make sure to refer to the schema to speed up the review process.

When submitting your pull request, you must squash multiple changes to a single commit, again there are instructions in the README for how to do this.

Remember to add authentication to your mntner object, and sign your commit

The registry includes a number of scripts to help check your request:

  • fmt-my-stuff <FOO>-MNT: automatically fixes minor formatting errors
  • check-my-stuff <FOO>-MNT: validates your objects against the registry schema
  • check-pol origin/master <FOO>-MNT: checks for policy violations
  • squash-my-commits: automatically update and squash your local commits
  • sign-my-commit: sign your commit using a pgp key or standard SSH signing

The registry maintainers run the checking scripts against each request, so please run these yourself first to check for simple errors.

Do browse through the registry and look at the pull request queue to see examples, understand how the process works and see the types of questions asked by the registry maintainers.

You should not use the gitea web interface to edit files, doing so would create a large number of commits and prevents running of the registry scripts

This example assumes that your name is <FOO>, part of an organisation called <FOO-ORG> (for instance, your hackerspace). Organisation objects are not required if your are registering as an individual. Obviously, these should be replaced by the appropriate values in all examples below.

We will create several types of objects:

  • maintainer objects, which are authenticated so that only you can edit your own objects
  • person objects, which describe people or organisations and provide contact information
  • and resource objects (AS number, IP subnet, DNS zone, etc).

All objects are simple text files in the specific subfolders, but the files do have a particular format. The files should use spaces and not tabs, and the attribute values must start on the 20th column.

Create a maintainer object

Create a mntner object in data/mntner/ named <FOO>-MNT. It will be used to edit all the objects that are under your responsibility.

  • use <FOO>-MNT as mnt-by, otherwise, you won't be able to edit your maintainer object.
  • Add an 'auth' attribute so that changes to your objects can be verified.

The auth attribute is used to verify changes to your object. There is a separate page on registry authentication which details what to include in your mntner object, how to sign and verify your commits.

Common authentication methods are:

  • PGP Key: auth: pgp-fingerprint <pgp-fingerprint>
  • SSH Key: auth: ssh-{rsa,ed25519} <key>

Example: data/mntner/FOO-MNT

mntner:             FOO-MNT
admin-c:            FOO-DN42
tech-c:             FOO-DN42
mnt-by:             FOO-MNT
auth:               pgp-fingerprint 0123456789ABCDEF0123456789ABCDEF01234567
source:             DN42

Create person objects

Create a person object in data/person/ for yourself (not your organisation/hackerspace/whatever).

  • use something like <FOO>-DN42 as nic-hdl, it should end with -DN42.
  • the person field is more freeform, you may use your nickname or even real name here.
  • provide an email.
  • you may provide additional ways of contacting you, using one or more contact field. For instance xmpp:[email protected], irc:luke42@hackint, twitter: TheGreatLuke.
  • you may wish to add other fields, such as pgp-fingerprint, remarks, and so on.
  • don't forget to set mnt-by to <FOO>-MNT.

Data Privacy

Contact attributes are optional but DN42 is a dynamic network and being able to contact users is really important if there are changes or problems. However, please also be aware that the DN42 registry is a public resource and you must assume that any details provided will be made public and cannot be fully removed. If this is a concern for you, please do not provide bogus contact details; simply provide anonymous details that are specific for use within DN42 or leave them out entirely.

Example: data/person/FOO-DN42

person:             John Doe
nic-hdl:            FOO-DN42
mnt-by:             FOO-MNT
source:             DN42

Organisations are not required if you are joining dn42 as an individual

If you intend to register resources for an organisation (e.g. your hackerspace), you must also create an organisation object for your organisation:

  • organisation is of the form <ORG-FOO>.
  • org-name should be the name of your organisation.
  • e-mail should be a contact address for your organisation, or maybe a mailing list (but people should be able to send email without subscribing).
  • admin-c, tech-c, and abuse-c may point to person objects responsible for the respective role in your organisation.
  • you may provide a website (www field).
  • don't forget to set mnt-by to <FOO>-MNT, since you're managing this object on behalf of your organisation.

Example: data/organisation/ORG-EXAMPLE

organisation:       ORG-FOO
org-name:           Foo Organisation
admin-c:            FOO-DN42
tech-c:             FOO-DN42
mnt-by:             FOO-MNT
source:             DN42

Guidelines for resource objects

From now on, you should use:

  • admin-c: <FOO>-DN42 and tech-c: <FOO>-DN42 for your own resources.
  • admin-c: <FOO>-DN42, tech-c: <FOO>-DN42 and org: <ORG-FOO> for the resources of your organisation.
  • mnt-by: <FOO>-MNT for all objects, so that you can edit them later.

This applies to AS numbers, network prefixes, routes, DNS records…

Register an AS number

To register an AS number, create an aut-num object in data/aut-num/.
as-name should be a name for your AS.

Your AS number can be chosen arbitrarily in the dn42 ASN space, see the as-block objects in the registry.

You should allocate your AS number in the 4242420000-4242423999 range

dn42regsrv includes a page for finding free ASN. For a list of currently assigned AS numbers browse the registry data/aut-num/ directory or online.

If you intend to use an ASN outside of the native dn42 ranges, please check that it doesn't clash with the [Freifunk AS-Numbers] ( or other networks (ChaosVPN, etc).

Internet ASNs may be used, but you must take care to clearly separate Internet and DN42 routes and prevent routes leaking between the networks. For Internet ASNs, the source attribute must be the originating registry and you will be required to prove you are the owner of the ASN.

If unsure, ask on the mailing list or IRC.

Example: data/aut-num/AS4242423999

aut-num:            AS4242423999
as-name:            AS-FOO-DN42
admin-c:            FOO-DN42
tech-c:             FOO-DN42
mnt-by:             FOO-MNT
source:             DN42

Register a network prefix


To register an IPv6 prefix, you create an inet6num object. dn42 uses the fd00::/8 (ULA) range. A single /48 allocation is typical and will likely provide more than enough room for all devices you will ever connect.

dn42 is interconnected with other networks, like icvpn, which also use the same ULA range so a registration in the dn42 registry can't prevent IPv6 conflicts. A fully random prefix (see RFC4193) is recommended; finding a conflict and needing to renumber your network is no fun.

A few websites can generate random ULA prefixes for you:

or a small script is available:

example: data/inet6num/fd35:4992:6a6d::_48

inet6num:           fd35:4992:6a6d:0000:0000:0000:0000:0000 - fd35:4992:6a6d:ffff:ffff:ffff:ffff:ffff
cidr:               fd35:4992:6a6d::/48
netname:            FOO-NETWORK
descr:              Network of FOO
country:            XD
admin-c:            FOO-DN42
tech-c:             FOO-DN42
mnt-by:             FOO-MNT
status:             ASSIGNED
source:             DN42

IPv4 (Legacy)

If you also want to register an IPv4 network prefix, simply create an inetnum object.

You may choose your network prefix in one of the currently open netblocks. You can get a list of unassigned subnets on the following site, please mind the allocation guideline below.

If there are no free subnets of the size you want, you may split a larger block as required.

Check the registry (data/inetnum) to make sure no-one else has allocated the same prefix. There are some IP ranges that are not open for assignments or are reserved for specific uses, so you should also check that the parent block has an 'open' policy. A quick and simple way to see the block policies is to run grep "^policy" data/inetnum/*.

Size Comment
/29 starter pack
/28 usually enough
/27 default allocation
/26 usually enough
/25 still a lot of IPs!
/24 are you an organization?

The current guideline is to allocate a /27 or smaller by default, keeping space for up to a /26 if possible. Don't allocate more than a /25 worth of addresses and please think before you allocate.

dn42 typically uses point-to-point addressing in VPN tunnels making transit network unnecessary, a single IP address per host should be sufficient. If you are going to have 2-3 servers, a /28 is plenty; same will go for most home-networks. dn42 is not the public internet, but our IPv4-space is valuable too!

If you need a /24 or larger, please ask in the IRC chan or on the mailing list and expect to provide justification. You should also ensure the range you've requested is in a suitable block.

Note: Reverse DNS works with any prefix length, as long as your recursive nameserver supports RFC 2317. Don't go for a /24 just to have RDNS.

example: data/inetnum/

inetnum:   -
netname:            FOO-NETWORK
descr:              Network of FOO
country:            XD
admin-c:            FOO-DN42
tech-c:             FOO-DN42
mnt-by:             FOO-MNT
status:             ASSIGNED
source:             DN42

Create route objects

If you plan to announce your prefixes in dn42, which you probably want in most cases, you will also need to create a route6 object for ipv6 prefixes and a route object for ipv4 prefixes. This information is used for Route Origin Authorization (ROA) checks. If you skip this step, your network will probably get filtered by most major peers. Checking ROA will prevent (accidental) hijacking of other people's prefixes.

example: data/route6/fd35:4992:6a6d::_48

route6:             fd35:4992:6a6d::/48
origin:             AS4242423999
max-length:         48
mnt-by:             FOO-MNT
source:             DN42

example data/route/

origin:             AS4242423999
max-length:         27
mnt-by:             FOO-MNT
source:             DN42
Note: the "max-length" should be the same as the prefix length (i.e. 27 for default ipv4 allocation size and 48 for default ipv6 allocation size) except if you have special needs in announcing larger prefixes

DNS and Domain Registration

To register a domain name, create a dns object in the data/dns directory.
Domain names and nserver attributes must be lowercase.

example: data/dns/foo.dn42

domain:             foo.dn42
admin-c:            FOO-DN42
tech-c:             FOO-DN42
mnt-by:             FOO-MNT
nserver:   fd35:4992:6a6d:53::1
nserver:   fd35:4992:6a6d:53::2
source:             DN42

You can also add DNSSEC delegations using ds-rdata attributes to your domain:

ds-rdata:           61857 13 2 bd35e3efe3325d2029fb652e01604a48b677cc2f44226eeabee54b456c67680c

For reverse DNS, add nserver attributes to you inet{,6}num objects:

inet6num:           fd35:4992:6a6d:0000:0000:0000:0000:0000 - fd35:4992:6a6d:ffff:ffff:ffff:ffff:ffff
cidr:               fd35:4992:6a6d::/48
netname:            FOO-NETWORK
descr:              Network of FOO
country:            XD
admin-c:            FOO-DN42
tech-c:             FOO-DN42
mnt-by:             FOO-MNT
status:             ASSIGNED
source:             DN42

Get some peers

In dn42, there is no real distinction between peering and transit: in most cases, everybody serves as an upstream provider to all their peers. Note that if you have very slow connectivity to the Internet, you may want to avoid providing transit between your peers, which can be done by filtering or prepending your ASN. For the sake of sane routing, try to peer with people on the same continent to avoid inefficient routing, <50ms is a good rule of thumb. You can also look into Bird communities if you are using Bird to mark the latency for the link.

You can use the peerfinder to help you find potential peers close to you:

You can then contact them on IRC or by email. In case you're really at loss, you can also ask for peers on the mailing list.

Establishing tunnels

Unless your dn42 peers are on the same network, you must establish tunnels. Choose anything you like: Wireguard, OpenVPN, GRE, GRE + IPSec, IPIP, Tinc, …

There is some documentation in this wiki, like gre-plus-ipsec.

Running a routing daemon

You need a routing daemon to speak BGP with your peers. People usually run Bird or FRR, but you may use anything (OpenBGPD, XORP, somebody even used an old hardware router ). See the relevant FAQ entry.

You can find configuration examples for Bird here.

Configuration Examples

Configure DNS

See Services DNS.

Use and provide services

See internal for internal services.

Don't hesitate to provide interesting services, but please, document them on the wiki! Otherwise, nobody will use them because nobody can guess they even exist.