asn.dev

Observed topology

AS21430 WIA-AS

Upstreams 12 carry this network
Downstreams 8 this network carries
Adjacent (IPv4) 21
Adjacent (IPv6) 12

Transit

Upstream networks

inferred

Networks observed carrying traffic for AS21430: 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
AS1299Arelion Sweden ABTransitIPv41,524
AS3491PCCW Global (HK) Ltd.TransitIPv4 IPv6702
AS6939Hurricane Electric LLCTransitIPv4 IPv6667
AS39392SH.cz s.r.o.HostingIPv4 IPv6468
AS3257GTT Communications Inc.TransitIPv4 IPv6442
AS29504Freenet Liberec, z.s.UnclassifiedIPv4 IPv670
AS24482SG.GSHostingIPv4 IPv670
AS37721Virtual Technologies & SolutionsResidentialIPv4 IPv666
AS57463NetIX Communications JSCUnclassifiedIPv465
AS1764Next Layer Telekommunikationsdienstleistungs- und Beratungs GmbHUnclassifiedIPv4 IPv611
AS8218Zayo Infrastructure France SAUnclassifiedIPv4 IPv66
AS47200NIX.CZ z.s.p.o.UnclassifiedIPv41

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.

Transit

Downstream networks

inferred

Networks for which AS21430 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS203376Mailkit s.r.o.UnclassifiedIPv4 IPv6144
AS33943Eri Internet s.r.o.UnclassifiedIPv4 IPv694
AS15614Dragon Internet a.s.ResidentialIPv487
AS12608IGLG Network CZ s.r.o.HostingIPv460
AS209369The Cloud Provider s.r.o.HostingIPv447
AS48451Prazska energetika, a.s.UnclassifiedIPv4 IPv638
AS42189Druzstvo EUROSIGNALUnclassifiedIPv432
AS39761ABAK, Co.Ltd.UnclassifiedIPv410

Adjacency

Adjacent networks

33 shown

Every AS seen directly next to AS21430 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS1299Arelion Sweden ABTransitIPv41,612
AS3491PCCW Global (HK) Ltd.TransitIPv4 IPv6894
AS6939Hurricane Electric LLCTransitIPv4 IPv6715
AS3257GTT Communications Inc.TransitIPv4 IPv6621
AS39392SH.cz s.r.o.HostingIPv4 IPv6515
AS203376Mailkit s.r.o.UnclassifiedIPv4 IPv6144
AS15614Dragon Internet a.s.ResidentialIPv4135
AS33943Eri Internet s.r.o.UnclassifiedIPv4 IPv694
AS24482SG.GSHostingIPv4 IPv678
AS29504Freenet Liberec, z.s.UnclassifiedIPv4 IPv678
AS37721Virtual Technologies & SolutionsResidentialIPv4 IPv677
AS209369The Cloud Provider s.r.o.HostingIPv468
AS57463NetIX Communications JSCUnclassifiedIPv467
AS12608IGLG Network CZ s.r.o.HostingIPv460
AS48451Prazska energetika, a.s.UnclassifiedIPv4 IPv638
AS42189Druzstvo EUROSIGNALUnclassifiedIPv432
AS39761ABAK, Co.Ltd.UnclassifiedIPv420
AS1764Next Layer Telekommunikationsdienstleistungs- und Beratungs GmbHUnclassifiedIPv4 IPv616
AS8218Zayo Infrastructure France SAUnclassifiedIPv4 IPv68
AS47200NIX.CZ z.s.p.o.UnclassifiedIPv41
AS15935ha-vel internet s.r.o.UnclassifiedIPv41

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.

Interconnection

Exchange presence

recorded

Internet exchanges where Packet Clearing House has a port recorded for AS21430, largest fabric first. An exchange is shared switching where networks interconnect directly rather than paying a transit provider to carry traffic between them, so turning up at one is a deliberate choice about how this network wants to be reached. Each name opens that exchange's own page, with its peering LANs and every other network recorded on it. Recorded at 1 exchange across 1 country and 1 region.

ExchangeLocationTheir addressMember ports
Peering.czPrague, Czech Republic185.0.20.26212

Unlike the tables above, this is recorded rather than inferred. An address on a peering LAN is at that exchange by definition. Two carve-outs all the same. Member ports counts every participant at the exchange, not this network's ports, so read it as a size proxy. And an absent exchange means PCH has no record of it, not that the network is not there.

Provenance

Where this comes from

Derived from routing tables collected at 2026-08-08 10:00 UTC by route-views2,rrc00, as seen from 75 BGP vantage points across 74.02M route entries. These are observations from those vantage points, not a complete or authoritative view of the internet.

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

Exchange presence comes from a separate dataset: the directory collected 2026-08-09 by Packet Clearing House (https://www.pch.net/ixp/data), covering 1,327 exchanges and 93,164 recorded member ports, licensed CC BY-NC-SA 3.0.

PeeringDB is the better-known directory and is deliberately not the source here: its acceptable-use policy forbids the bulk storage this needs. The two answer different questions anyway. PeeringDB reports what an operator declares about itself; this reports what PCH has recorded.