asn.dev

Observed topology

AS203851 AS_CSD001

Unclassified RIPE

Upstreams 12 carry this network
Downstreams 2 this network carries
Adjacent (IPv4) 14
Adjacent (IPv6) 0
Upstream graph Who carries AS203851, and who carries them, drawn as a map up to the transit-free core. 1 exchange Where AS203851 physically turns up to peer, and its address on each fabric.

Transit

Upstream networks

All 12

Networks observed carrying traffic for AS203851: 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
AS6939Hurricane Electric LLCTransitIPv4205
AS174Cogent Communications, LLCTransitIPv460
AS34549meerfarbig GmbH & Co. KGHostingIPv415
AS3741Dimension DataUnclassifiedIPv45
AS17639Converge ICT Solutions Inc.UnclassifiedIPv45
AS24482SG.GSHostingIPv45
AS37100SEACOM LimitedUnclassifiedIPv45
AS37721Virtual Technologies & SolutionsResidentialIPv45
AS48185team.blue NVUnclassifiedIPv45
AS48362Stadtwerke FeldkirchResidentialIPv45

All 12 upstreams →

Transit

Downstream networks

inferred

Networks for which AS203851 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS205900APC Solutions UK LtdUnclassifiedIPv4195
AS210206Metro Security (GB) PLCUnclassifiedIPv464

Adjacency

Adjacent networks

All 14

Every AS seen directly next to AS203851 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS6939Hurricane Electric LLCTransitIPv4380
AS205900APC Solutions UK LtdUnclassifiedIPv4195
AS174Cogent Communications, LLCTransitIPv4104
AS210206Metro Security (GB) PLCUnclassifiedIPv464
AS34549meerfarbig GmbH & Co. KGHostingIPv427
AS3741Dimension DataUnclassifiedIPv49
AS17639Converge ICT Solutions Inc.UnclassifiedIPv49
AS24482SG.GSHostingIPv49
AS37100SEACOM LimitedUnclassifiedIPv49
AS37721Virtual Technologies & SolutionsResidentialIPv49

All 14 adjacent →

Provenance

Where this comes from

Derived from routing tables collected at 2026-10-26 10:00 UTC by route-views2,rrc00, as seen from 75 BGP vantage points across 73.14M 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.