02 / 04 · Technical Documentation
Filters and BIRD features
Import filters of the route servers in configuration order, and the active BIRD features.
Import filters#
Order of the checks on import, as they appear in the configuration. If a check matches, the route is not passed on, but remains visible in the looking glass together with the reason (community 214591:1101:<reason>, see BGP communities).
| Check | Rule |
|---|---|
| Prefix length IPv4 | longer than /24 is rejected |
| Prefix length IPv6 | longer than /48 is rejected |
| Bogons / martians | RFC 1918, documentation, link-local, multicast and other reserved networks; for IPv6 additionally ULA, 6bone, invalid 6to4 |
| Empty AS path | rejected |
| First AS in path | must be the member's ASN |
| Next hop | must be a peering address of the member; another router of the same member is allowed |
| Transit ASNs in path | rejected for 174, 701, 1299, 2914, 3257, 3320, 3356, 3491, 4134, 5511, 6453, 6461, 6762, 6830, 7018 |
| AS path too long | more than 64 entries |
| RPKI | invalid is rejected; valid and unknown are passed on and tagged |
| IRRDB | prefix and origin AS must be in the member's AS-SET (source: RADB, RIPE, ARIN depending on the member); refreshed every six hours |
Further features#
All active:
- RFC 8092 large communities for steering (see BGP communities). Classic communities cannot be used for steering because AS214591 is a 32-bit ASN.
- RFC 8326 graceful shutdown: routes carrying the community
65535:0get local preference 0. Members can use this to announce maintenance without tearing down the session. - Communities are passed through: the route server does not interpret the well-known communities itself (
interpret communities off), so members see NO_EXPORT and the like exactly as the sender set them. Only exception: all communities with 214591 as the first part are removed on export. - Separate table per member: every session has its own routing table; filter decisions can be traced per peer in the looking glass.
- Delayed session start after a route server restart, so that the RPKI data is available before the first route.
Looking glass: manager.frankonix.net/lg
Technical questions: support@frankonix.net
Last updated: November 2026