asn.dev

Observed topology

AS43037 SEZNAM-

Upstreams 22 carry this network
Downstreams 1 this network carries
Adjacent (IPv4) 20
Adjacent (IPv6) 17

Transit

Upstream networks

inferred

Networks observed carrying traffic for AS43037: 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
AS5610O2 Czech Republic, a.s.UnclassifiedIPv4 IPv6201
AS6939Hurricane Electric LLCTransitIPv4 IPv6121
AS29208Quantcom, a.s.UnclassifiedIPv4 IPv663
AS34549meerfarbig GmbH & Co. KGHostingIPv4 IPv635
AS17639Converge ICT Solutions Inc.UnclassifiedIPv4 IPv612
AS24482SG.GSHostingIPv4 IPv612
AS29504Freenet Liberec, z.s.UnclassifiedIPv4 IPv612
AS48362Stadtwerke FeldkirchResidentialIPv4 IPv612
AS1836green.ch AGResidentialIPv4 IPv612
AS34019Hivane AssociationUnclassifiedIPv4 IPv612
AS212024Marc SchmittUnclassifiedIPv4 IPv612
AS29632Netassist International EOODUnclassifiedIPv611
AS12859BIT BVHostingIPv4 IPv611
AS37721Virtual Technologies & SolutionsResidentialIPv4 IPv68
AS12779IT.Gate S.p.A.UnclassifiedIPv46
AS20485Joint Stock Company TransTeleComUnclassifiedIPv46
AS56662Marcin GondekUnclassifiedIPv66
AS37100SEACOM LimitedUnclassifiedIPv46
AS57463NetIX Communications JSCUnclassifiedIPv46
AS12552GlobalConnect ABUnclassifiedIPv46
AS47232ISP Alliance a.s.ResidentialIPv46
AS213241TECHIT.BE SRLResidentialIPv66

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 AS43037 was observed as the last hop before the origin, meaning it appears to provide them transit.

ASNetworkTypeFamiliesPaths seen
AS200600Seznam.cz datova centra, s.r.o.HostingIPv4 IPv696

Adjacency

Adjacent networks

37 shown

Every AS seen directly next to AS43037 in a routing path, in either direction.

ASNetworkTypeFamiliesPaths seen
AS5610O2 Czech Republic, a.s.UnclassifiedIPv4 IPv6234
AS6939Hurricane Electric LLCTransitIPv4 IPv6140
AS200600Seznam.cz datova centra, s.r.o.HostingIPv4 IPv696
AS29208Quantcom, a.s.UnclassifiedIPv4 IPv674
AS34549meerfarbig GmbH & Co. KGHostingIPv4 IPv640
AS48362Stadtwerke FeldkirchResidentialIPv4 IPv614
AS1836green.ch AGResidentialIPv4 IPv614
AS34019Hivane AssociationUnclassifiedIPv4 IPv614
AS212024Marc SchmittUnclassifiedIPv4 IPv614
AS29504Freenet Liberec, z.s.UnclassifiedIPv4 IPv614
AS24482SG.GSHostingIPv4 IPv614
AS29632Netassist International EOODUnclassifiedIPv613
AS12859BIT BVHostingIPv4 IPv613
AS17639Converge ICT Solutions Inc.UnclassifiedIPv4 IPv613
AS37721Virtual Technologies & SolutionsResidentialIPv4 IPv611
AS57463NetIX Communications JSCUnclassifiedIPv47
AS47232ISP Alliance a.s.ResidentialIPv47
AS37100SEACOM LimitedUnclassifiedIPv47
AS12779IT.Gate S.p.A.UnclassifiedIPv47
AS20485Joint Stock Company TransTeleComUnclassifiedIPv47
AS56662Marcin GondekUnclassifiedIPv67
AS12552GlobalConnect ABUnclassifiedIPv47
AS213241TECHIT.BE SRLResidentialIPv67

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 AS43037, 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
DE-CIX FrankfurtFrankfurt, Germany80.81.196.1311,073

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.