Route server

What is a route server

A route server redistributes BGP routes received from its BGP clients to other clients according to a policy. By peering with a route server, customers can avoid separate BGP sessions with all their peers and instead limit the number of sessions to one with each route server.

NIX offers redundant route servers on the NIX1 peering VLAN. Route server configuration is generated by ixpmanager, and hence is based on information entered here, allowing ixpmanager to be the center of our universe.

NIX Route Server Details

Name nix-rs1 nix-rs2
ASN 44997 44997
IPv4 185.1.55.251 185.1.55.252
IPv6 2001:7f8:12:1:0:1:4:4997 2001:7f8:12:1:0:2:4:4997
Platform BIRD BIRD

Route Server Filtering

Basic filtering blocks RFC1918 address ranges, martian prefixes, and too long and too short routes.

BIRD config:

# This function excludes weird networks
#  rfc1918, class D, class E, too long and too short prefixes
function avoid_martians()
prefix set martians;
{
        martians = [
                10.0.0.0/8+,
                169.254.0.0/16+,
                172.16.0.0/12+,
                192.0.0.0/24+,
                192.0.2.0/24+,
                192.168.0.0/16+,
                198.18.0.0/15+,
                198.51.100.0/24+,
                203.0.113.0/24+,
                224.0.0.0/4+,
                240.0.0.0/4+,
                0.0.0.0/32-,
                0.0.0.0/0{27,32},
                0.0.0.0/0{0,7}
        ];

        # Avoid RFC1918 and similar networks
        if net ~ martians then
                return false;

        return true;
}

Filtering is further done based on IRRdb lookup, so that only prefixes present in AS’s announced AS/AS-SET are allowed.

Controlling outbound routing information can be done by sending BGP communities as as follows:

  • block announcement of a route to certain peer (0:<peer AS>)
  • announce a route to a certain peer (44997:<Peer AS>)
  • block announcement of a route to all peers (0:44997)
  • announce a route to all peers (default behavior)

 

Publisert 27. apr. 2018 11:55 - Sist endret 28. mai 2018 09:13