asn.dev

Observed topology

AS21309 CASAWEB-AS Via Molino Rosso 8 IMOLA BO ITALY

Residential RIPE

Upstreams 9 carry this network
Downstreams 10 this network carries
Adjacent (IPv4) 18
Adjacent (IPv6) 7
Upstream graph Who carries AS21309, and who carries them, drawn as a map up to the transit-free core. 1 exchange Where AS21309 physically turns up to peer, and its address on each fabric.

Transit

Upstream networks

inferred

Networks observed carrying traffic for AS21309: 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
AS174Cogent Communications, LLCTransitIPv4 IPv6782
AS9002RETN LimitedUnclassifiedIPv4 IPv6700
AS6939Hurricane Electric LLCTransitIPv4 IPv6523
AS6762TELECOM ITALIA SPARKLE S.p.A.TransitIPv4 IPv6383
AS24482SG.GSHostingIPv4 IPv647
AS59919Brainbox S.r.l.ResidentialIPv446
AS29075IELO-LIAZO SERVICES SASUnclassifiedIPv420
AS31543myNet GmbHResidentialIPv420
AS13030Init7 (Switzerland) Ltd.HostingIPv61

Transit

Downstream networks

inferred

Networks for which AS21309 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS197807Eos sistemi s.r.l.UnclassifiedIPv4 IPv6412
AS31495HERABIT S.p.A.UnclassifiedIPv458
AS211102Previnet S.p.A.UnclassifiedIPv452
AS214164Interporto Padova S.p.A.UnclassifiedIPv435
AS49535E-Mind SrlResidentialIPv424
AS42933Aeroporto G. Marconi di Bologna s.p.a.UnclassifiedIPv414
AS35514GEOX S.P.A.UnclassifiedIPv412
AS15923Logos S.P.A.UnclassifiedIPv49
AS207157CAME S.P.A.UnclassifiedIPv44
AS8884CRIF S.p.A.UnclassifiedIPv43

Adjacency

Adjacent networks

All 19

Every AS seen directly next to AS21309 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS174Cogent Communications, LLCTransitIPv4 IPv61,067
AS9002RETN LimitedUnclassifiedIPv4 IPv6871
AS6939Hurricane Electric LLCTransitIPv4 IPv6630
AS197807Eos sistemi s.r.l.UnclassifiedIPv4 IPv6412
AS6762TELECOM ITALIA SPARKLE S.p.A.TransitIPv4 IPv6407
AS59919Brainbox S.r.l.ResidentialIPv463
AS24482SG.GSHostingIPv4 IPv661
AS31495HERABIT S.p.A.UnclassifiedIPv458
AS211102Previnet S.p.A.UnclassifiedIPv452
AS214164Interporto Padova S.p.A.UnclassifiedIPv435

All 19 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.