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Autonomous System

AS25151 ยท Cyso Group B.V.

Overview

AS25151 is announced on the Internet: RIPE RIS route collectors currently see 15 IPv4 prefixes and 3 IPv6 prefixes originated by this network. Together, its IPv4 prefixes cover 15,872 addresses, with overlapping prefixes counted once. In the paths the collectors record, it has 57 upstream neighbours (transit providers or peers) and 2 downstream neighbours (customers or networks it carries). Its most visible upstreams are Level 3 Parent, LLC (AS3356), Arelion Sweden AB (AS1299), and Stichting NBIP-NaWas (AS200020). AS25151 was assigned by RIPE NCC, and its registration country is Netherlands.

Source: RIPEstat (RIPE NCC), RIS route collectors. Read on October 16, 2026 at 11:43 PM UTC. This page is refreshed at most every 12 hours.

Go further

The trace goes to 81.24.0.1, the first address of 81.24.0.0/20. An address picked inside a prefix may not answer (nothing listens there, or the network filters probes): the trace then shows the path up to the last network that replies.

Announced prefixes

IPv4 prefixes (15 prefixes)

PrefixAddresses
2.57.56.0/24256
37.46.136.0/212,048
37.72.138.0/24256
45.134.223.0/24256
62.129.139.0/24256
62.129.149.0/24256
80.85.160.0/23512
81.24.0.0/204,096
85.158.200.0/212,048
93.94.224.0/212,048
109.235.72.0/212,048
130.193.5.0/24256
185.54.112.0/221,024
185.123.55.0/24256
193.33.220.0/24256

IPv6 prefixes (3 prefixes)

Prefix
2001:678:c50::/48
2a01:518::/32
2a05:6cc0::/29

Neighbours

Upstreams (transit or peers) (57)

ASNetworkVisibility
AS3356Level 3 Parent, LLC257
AS1299Arelion Sweden AB175
AS200020Stichting NBIP-NaWas131
AS2914NTT America, Inc.109
AS6939Hurricane Electric LLC104
AS13030Init7 (Switzerland) Ltd.20
AS33891Core-Backbone GmbH15
AS6777Amsterdam Internet Exchange B.V.14
AS9002RETN Limited13
AS25091IP-Max SA13
AS34019Hivane Association11
AS5405Inter.link GmbH8
AS8298IPng Networks GmbH8
AS50673Serverius Holding B.V.8
AS35280F5 Networks SARL7
AS37497Network Platforms (PTY) LTD7
AS61049Exascale Ltd7
AS14840BR.Digital Telecom6
AS20764CJSC RASCOM6
AS24961WIIT AG6
AS29632Netassist International EOOD6
AS34177Celeste SAS6
AS34927iFog GmbH6
AS3935131173 Services AB6
AS41327Fiber Telecom S.p.A.6
AS48362Stadtwerke Feldkirch6
AS12779IT.Gate S.p.A.5
AS47147Anexia Cloud Solutions GmbH5
AS1267WIND TRE S.P.A.4
AS3216PJSC "Vimpelcom"4

The 30 most visible of 57.

Downstreams (customers) (2)

ASNetworkVisibility
AS15535Virtual Access Internet BV262
AS210728Cyso Group B.V.45

49 more neighbours appear on both sides of this network depending on the path, so they are counted in neither list.

Visibility is RIPEstat's count of how often the route collectors observed the link. It compares neighbours with each other; it is not a traffic volume.

How to read this page

An Autonomous System (AS) is a network run under one routing policy: an internet provider, a cloud, a content network, a university. Each one has a number, its ASN, assigned by a regional registry (ARIN, RIPE NCC, APNIC, LACNIC, AFRINIC), and uses BGP, the protocol networks use to tell each other where addresses are, to announce the blocks of addresses it delivers to.

A prefix such as 203.0.113.0/24 is a block of addresses: the number after the slash says how many bits are fixed, so a /24 holds 256 IPv4 addresses and a /16 holds 65,536. Networks often announce a large block and smaller pieces of it at the same time, which is why the address total counts each address once.

Neighbours come from the paths themselves. A network that appears just before this one in a path, on the collector's side, is an upstream: a transit provider or a peer. One that appears just after it is a downstream, usually a customer. Peering at an internet exchange also shows up as an upstream, so the upstream list is not a list of paid transit.

The data comes from RIPEstat, run by the RIPE NCC, which gathers the routing tables of hundreds of networks through its RIS route collectors. This page reads it when it is visited and keeps it for 12 hours at most; the BGP viewer reads it live.

Frequently asked questions

How do I find the ASN of an IP address?
Type the address in the BGP viewer: it shows the prefix that covers it, the AS that originates that prefix and the paths seen towards it. A traceroute also names the network of each hop, so you can see every AS a connection crosses.
Why does one company have several ASNs?
Large operators split their network by region, by activity or by history: a cloud may use one number for its backbone and another for a region, and every acquisition brings its own numbers. Each number has its own page, with its own prefixes and neighbours.
Why do prefix counts differ from one site to another?
Each source sees the routing table from different collectors, at a different time, and counts differently: some include prefixes withdrawn in recent weeks, some merge a block and its pieces. This page counts the prefixes RIPE RIS collectors see originated by the network at the end of the latest two-week window, and counts each IPv4 address once.
Is this the list of IP ranges of a cloud provider?
It is what its networks announce, which is what the Internet routes to them. Many providers also publish an official list of ranges per service and region; that list is the reference for firewall rules, because a range can be announced before it is used, or announced by another of their AS numbers.