= Policies =

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

== Routing ==
=== AS Number ===
You can use your own RIPE AS # or a private one, which is 64600+n, where n is 172.22.n.0/25. [[BR]]
'''Don't use public AS # which are not yours! [[BR]]
ICANN IS qualified to decide which ASNs belong to whom! '''

=== 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:[[BR]]
{{{ match to group "DN42" set prepend-self 2 }}} [[BR]]
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 [http://tools.ietf.org/html/rfc1918#section-3 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.