how can I know since when has a BGP prefix been allocated?

ℕʘʘḆḽḘ asked:

I am a bit confused.

I would like to know since when a current ASN (and its corresponding prefixes) have been in place.

When I look at the example at team-cymru ( I see:

$ whois -h " -v 2005-12-25 13:23:01 GMT"

AS      | IP               | BGP Prefix          | CC | Registry | Allocated  | Info                    | AS Name
23028   |    |     | US | arin     | 1998-09-25 | 2005-12-25 13:23:01 GMT | TEAMCYMRU - SAUNET
You may also query for some basic AS information directly:

$ whois -h " -v AS23028"

AS      | CC | Registry | Allocated  | AS Name
23028   | US | arin     | 2002-01-04 | TEAMCYMRU - SAUNET

So, the ASN 23028 and it BGP prefix have been allocated in 1998 or in 2002?


My answer:

The netblock the IP address is in was originally allocated on 1998-09-24.

The autonomous system number 23028 was registered on 2002-01-04.

Their registration dates have no relation to each other, nor is there any reason for them to. IP netblocks and AS numbers are independent. Routes can change at any time. So can ASNs.

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