Policies

These are Routing-Policies, there are no real Usage Policy.

Routing

Transit AS

Prepend your one AS one time if you participate from an DSL and an other time if you have less than a 10 mbit/s full-duplex connection.

Assuming you have all your dn42 peers in one group this can be implemented with OpenBGPd by appending this to your bgpd.conf:
match to group "DN42" set prepend-self 2
Read man 5 bgpd.conf vor details.

The quagga command is: set as-path prepend 9578 9578 (while 9578 is your own AS)

Subnet sizes

  • Networks smaller than /28 are being filtered by some people, /28 is meant to be the "smallest safe net size"
    • You may choose to use smaller subnets nevertheless. But please round up to /28 in your BGP configuration.
  • Host routes are being filtered. See above.

It is reasonable to use smaller subnets for yourself. You'll be having free addresses when you add more subnets.

IPv4 routes

  • 172.22.0.0/15 is the the dn42 range. All people should accept these routes. We don't want to think about intended collisions...
    • 172.23.0.0/16 isn't in use currently and for the foreseeable future. This is reserve.
  • Foreign  RFC1918 networks:
    • 192.168.x.0/24 where x = {0, 1, 2, 10, 100, 200, 254} is not welcome, collides with any ADSL/cable modem, home networks, default settings and causes disputes
    • 10.10.10.0/24 is being blocked by at least one user, ISP Kabel Deutschland has their DHCP servers there
    • Everything else depends on a peer's individual filters
    • Because of Freifunk peerings, keep your net out of 10.0.0.0/8 to avoid collisions
  • Foreign global-scoped networks:
    • Please announce in this Wiki to allow people update their filter lists

At all anyone may announce whatever he wishes to. It always depends on a peer's filters.

IPv6 routes

The Ranges mentioned in Topology are being used. Everything else may be filtered. It always depends on a peer's filters.

MTU

The smalles "regular" MTU is 1460, a "safe reserve" from some years ago. Also usual are 1472 (DSL - GRE) and 1476 (Ethernet - GRE). Some routers (OpenVPN) fragment automagically.

Firewalling

You MUST NOT filter routed traffic!

Whoever filters shall not announce routes.