131.143.87.0/24

Currently announced by AS200454 Tomas Oliveira Valente Leite de Castro, in the routed prefix 131.143.87.0/24.

Routing data · Nov 11, 2026, 20:24 UTC

ASN historyEvery routed prefix covering 131.143.87.0/24

Prefix	ASN	Name	Registered country	First seen (UTC)	Last seen (UTC)	Status
131.143.87.0/24	AS200454	Tomas Oliveira Valente Leite de Castro	Portugal	Before monitoring	2026-11-11 20:24	Announcing

No more specific routes inside this prefix.

Detected (UTC)	Prefix	Change	ASN	Name	Previous ASN	Country
2026-10-29 18:21	131.143.87.0/24	WithdrawalAnnounced again	AS200454	Tomas Oliveira Valente Leite de Castro	—	Portugal

From the RIRs’ delegated statistics files. Shows where the addresses are registered, not where they are used.

Every 2 hours ASNBase takes the bgp.tools global routing table (prefix → origin ASN) and compares it with the previous one. The detected time is the time of that comparison; the actual change can be up to about 2 hours earlier.
Only routes seen by more than 100 bgp.tools peers are listed as changes; routes with less visibility are only kept in the history.
A new announcement counts only if it is still in the next routing table, and a withdrawal only if the prefix is missing from two tables in a row, so short flaps are ignored.
ASNBase has been monitoring since 2026-10-19. “Before monitoring” under “First seen” means the route was already announced when monitoring started; the earlier date is unknown.
Prefixes first seen during the first day of monitoring do not count as new announcements: most of them were simply missing from the table at the moment monitoring started.
Countries and regions follow the ASN’s registration, not the actual location of the IP addresses.