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InterCity-VPN - Metadata registry (BGP, DNS, Subnet Allocations in

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InterCityVPN meta information

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The data in this repository can be used for automatic configuration of routing daemons and DNS servers. You may leave out fields that do not apply to your community (e.g. asn, domains and nameservers).

Stick to one file per community. The filename must match your communityname on the freifunk-api. You may add stub DNS zones (e.g. dn42, rzl, hack) by leaving out everything but domains and nameservers.

Scripts for the automatic configuration generation and provisioning of various services (bird, bind, dnsmasq, ...) are kept in a separate repository: icvpn-scripts

Notes on IPv4 allocations

  • There is only a limited amount of usuable IPv4 space available.
  • 10/8 is used for connections between community networks across the ICVPN.
  • Previously, people just took a /16, which means space is exhausted after 255 communites picked a network.
  • Thus: think before you allocate a v4 network here: do you really need IPv4 connectivity between your and other Freifunk networks? If not, consider to use IPs from or internally and do NOT announce them to ICVPN.
  • If you think you do, please be conservative; rule of thumb: Meshes might not size well beyond 2000 concurrent users, double that for decent DHCP timings => a /20 (4k IPs) per Mesh sounds reasonable. For additional systems outside the Mesh, an additional /22 (1024 IPv4 addresses) might be sufficient.
  • If you use mostly routing (OLSR), things might look different, you might look into e. g. an /21 to distribute to clients and another /22 for p2p-links if needed.
  • Again, please plan ahead, than take your pick. Be prepared to be questioned on why, if you took e. g. more than /18 directly. But remember as well, that renumbering IS a pain.
  • If you need more than a /18 in one community or city you need a very good explaination, why you do need it.
  • Minimum net size is /22, round up if you need less.


  # This is your ASN.
  asn: 65052

  # A list of people to contact in case of technical emergency.
  # Automated monitoring systems might use this.
  # Prefixes announced by your AS. This may be used for filtering
  # routes. Keep the prefixes a short as possible. If you're
  # assigned while you're using just a subnet of it
  # (e.g. you must include here. The details
  # will be taken care of by the routing daemons.
      - fdef:ffc0:3dd7::/48
      - 2001:bf7:110::/44

  # A list of BGP peers in IC-VPN announcing your AS.
      ipv6: fec0::a:cf:0:82
      ipv6: fec0::a:cf:0:83

  # If you're using custom TLDs, include them here.
  # Don't forget reverse zones!
    - ffhl

  # A list of nameservers capable of resolving your domains. 
  # All nameservers must be able to handle all domains listed above!
    - fdef:ffc0:3dd7::a01
    - fdef:ffc0:3dd7::e01

  # Delegate part of our network allocations to another community
  # this needs to be a subnet to an already allocated network in the
  # networks section.
    65038: # Darmstadt
      - fdef:ffc0:3dd7:ffda::/64


InterCity-VPN - Metadata registry (BGP, DNS, Subnet Allocations in






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