asn.dev

Observed topology

AS21453 FLEX-AS Flex Ltd.

Residential RIPE

Upstreams 12 carry this network
Downstreams 12 this network carries
Adjacent (IPv4) 25
Adjacent (IPv6) 12
Upstream graph Who carries AS21453, and who carries them, drawn as a map up to the transit-free core. 1 exchange Where AS21453 physically turns up to peer, and its address on each fabric.

Transit

Upstream networks

All 12

Networks observed carrying traffic for AS21453: the AS immediately before it in a routing path. Ranked by how many paths showed the relationship, which reflects how widely it is used, not how much traffic crosses it.

ASNetworkTypeFamiliesPaths seen
AS35598INETCOM CARRIER LLCUnclassifiedIPv4470
AS12389PJSC RostelecomResidentialIPv4 IPv6194
AS8641LLC "Nauka-Svyaz"UnclassifiedIPv4 IPv6122
AS1299Arelion Sweden ABTransitIPv4 IPv694
AS20764CJSC RASCOMUnclassifiedIPv494
AS28917Fiord Networks, UABUnclassifiedIPv4 IPv667
AS57304JSC "RetnNet"UnclassifiedIPv4 IPv636
AS29076Citytelecom LLCHostingIPv632
AS24482SG.GSHostingIPv4 IPv619
AS37721Virtual Technologies & SolutionsResidentialIPv417

All 12 upstreams →

Transit

Downstream networks

All 12

Networks for which AS21453 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS48149Ivanteevskie telecommunicacii LtdUnclassifiedIPv4 IPv6302
AS57489LLC "Telecom-Uslugi"UnclassifiedIPv4265
AS34975Azimut-R Ltd.UnclassifiedIPv4192
AS41783Informational technologies and electronic communications LLCUnclassifiedIPv4 IPv6164
AS201646Flex-l LtdUnclassifiedIPv4 IPv6163
AS43567UG-TELECOM Ltd.UnclassifiedIPv480
AS50449Limited Liability Company "Kvant"UnclassifiedIPv440
AS35271JSC "AVIEL"UnclassifiedIPv4 IPv637
AS49893Bitrace telecom Ltd.UnclassifiedIPv432
AS216335OOO Kalibr SBUnclassifiedIPv430

All 12 downstreams →

Adjacency

Adjacent networks

All 26

Every AS seen directly next to AS21453 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS12389PJSC RostelecomResidentialIPv4 IPv6773
AS35598INETCOM CARRIER LLCUnclassifiedIPv4564
AS48149Ivanteevskie telecommunicacii LtdUnclassifiedIPv4 IPv6309
AS8641LLC "Nauka-Svyaz"UnclassifiedIPv4 IPv6304
AS57489LLC "Telecom-Uslugi"UnclassifiedIPv4265
AS20764CJSC RASCOMUnclassifiedIPv4229
AS28917Fiord Networks, UABUnclassifiedIPv4 IPv6205
AS1299Arelion Sweden ABTransitIPv4 IPv6196
AS41783Informational technologies and electronic communications LLCUnclassifiedIPv4 IPv6195
AS34975Azimut-R Ltd.UnclassifiedIPv4192

All 26 adjacent →

Provenance

Where this comes from

Derived from routing tables collected at 2026-11-13 10:00 UTC by route-views2,rrc00, as seen from 75 BGP vantage points across 74.40M route entries. These are observations from those vantage points, not a complete or authoritative view of the internet.

Inferred from path position, not from any declaration by either party. A network appearing here is carrying these routes; whether that is a paid transit arrangement, a backup, or something else is not something routing data can tell you. Adjacency is not the same as peering. Being next to each other in a path covers paid transit, settlement-free peering and customer connections alike, and routing data cannot distinguish them. Treat this as "these networks exchange routes", nothing more specific.

Cross-check against RIPEstat or BGP.tools, which observe from a different and larger set of vantage points.