BGP communities
What AS218836 tags routes with, and what it acts on.
Informational
Every route we accept is tagged with large communities saying where it came from. Anything a peer, route server or upstream sends in the 218836:*:* namespace is stripped on import, so a tag always means what this page says. How many routes carry each one right now is on Communities in use.
| 218836:1:100 | learned from transit |
|---|---|
| 218836:1:200 | learned from a route server |
| 218836:1:300 | learned from a bilateral peer |
| 218836:1:400 | learned from a downstream |
| 218836:2:<ix> | PeeringDB id of the exchange it was learned at, 0 outside an exchange (26 AMS-IX, 3512 Frys-IX, 5106 Clue-IX) |
| 218836:3:<asn> | the neighbour ASN it was learned from |
| 218836:1000:1 | from a bilateral peer, covered by the peer's AS-SET |
| 218836:1000:0 | from a bilateral peer, not covered by the peer's AS-SET (or it has none); local preference lowered by 100 |
Well-known communities we honour
| 65535:0 | GRACEFUL_SHUTDOWN (RFC 8326): your route drops to the lowest preference |
|---|---|
| 65535:666 | BLACKHOLE (RFC 7999): traffic to the prefix is dropped. From a peer, RPKI applies first, so the length must be covered by a ROA |
| 65535:65281 | NO_EXPORT (RFC 1997): not announced to any other AS |
| 65535:65282 | NO_ADVERTISE (RFC 1997): not announced to anyone |
Action communities, for downstreams
If you buy transit from us, you can steer what happens to your routes with these. They are honoured on downstream sessions only, acted on per neighbour, and stripped before a route leaves AS218836. Where a community takes an <asn>, it is the neighbour's AS number; <ix> is the exchange's PeeringDB id.
| 218836:10:<asn> | do not announce to that AS |
|---|---|
| 218836:11:<ix> | do not announce at that exchange |
| 218836:12:100 | do not announce to transit |
| 218836:12:200 | do not announce to route servers |
| 218836:12:300 | do not announce to bilateral peers |
| 218836:21:<asn> | prepend once toward that AS; 0 means every neighbour |
| 218836:22:<asn> | prepend twice toward that AS; 0 means every neighbour |
| 218836:23:<asn> | prepend three times toward that AS; 0 means every neighbour |
| 218836:30:<asn> | announce only to the ASes named this way |
| 218836:40:<n> | set our local preference for the route to n, for a backup link; it is only ever lowered (customers default to 300, peers 200, route servers 150, transit 100) |
Blackholing, for downstreams
Announce any prefix inside your own space, down to a single address, with one of these. We drop the traffic at our edge and pass the blackhole on to our neighbours, always marked with 65535:666, so it is discarded before it reaches us. Withdraw the route to end it.
| 65535:666 | blackhole, announced to every neighbour |
|---|---|
| 218836:666:0 | the same as 65535:666 |
| 218836:666:<asn> | blackhole, announced to that AS only |
The same list is on bgp.tools. Questions go to the NOC.