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Autonomous System

AS2500 · WIDE Project

Overview

AS2500 is announced on the Internet: RIPE RIS route collectors currently see 3 IPv4 prefixes and 1 IPv6 prefix originated by this network. Together, its IPv4 prefixes cover 65,536 addresses, with overlapping prefixes counted once. In the paths the collectors record, it has 12 upstream neighbours (transit providers or peers) and 22 downstream neighbours (customers or networks it carries). Its most visible upstreams are NTT America, Inc. (AS2914), SoftBank Corp. (AS17676), and Hurricane Electric LLC (AS6939). AS2500 was assigned by ARIN, and its registration country is Japan.

Source: RIPEstat (RIPE NCC), RIS route collectors. Read on October 16, 2026 at 8:57 PM UTC. This page is refreshed at most every 12 hours.

Go further

Trace a route to this networkOpen in the BGP viewerWHOIS of 203.178.128.1

The trace goes to 203.178.128.1, the first address of 203.178.128.0/17. 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 (3 prefixes)

PrefixAddresses
133.4.128.0/1816,384
202.249.0.0/1816,384
203.178.128.0/1732,768

IPv6 prefixes (1 prefix)

Prefix
2001:200::/32

Neighbours

Upstreams (transit or peers) (12)

ASNetworkVisibility
AS2914NTT America, Inc.77,050
AS17676SoftBank Corp.32,947
AS6939Hurricane Electric LLC25,561
AS7660Asia Pacific Advanced Network - Japan6,639
AS9002RETN Limited1,688
AS2516KDDI CORPORATION219
AS141682APIDT Infrastructure Pty Ltd163
AS24482SG.GS139
AS7530BroadBand Tower, Inc.134
AS9583Sify Limited42
AS20326TeraSwitch Networks Inc.36
AS132132-16

Downstreams (customers) (22)

ASNetworkVisibility
AS141682APIDT Infrastructure Pty Ltd602
AS4690WIDE Project479
AS55384Japan Advanced Institute of Science and Technology373
AS17932Japan Advanced Institute of Science and Technology358
AS7660Asia Pacific Advanced Network - Japan288
AS23799National Defense Academy254
AS63783Chiba University of Commerce254
AS4717WIDE Project242
AS131158Nara Institute of Science and Technology, National University Corporation205
AS38635Keio University36
AS2907Research Organization of Information and Systems, National Institute of Informatics29
AS4718-22
AS4777Asia Pacific Network Information Centre20
AS7667-17
AS9367-14
AS2501-13
AS2515-13
AS10014-10
AS23634-8
AS2516KDDI CORPORATION6
AS6939Hurricane Electric LLC4
AS7500WIDE Project1

317 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.