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Autonomous System

AS51248 ยท Host-Telecom.com s.r.o.

Overview

AS51248 is announced on the Internet: RIPE RIS route collectors currently see 20 IPv4 prefixes and 5 IPv6 prefixes originated by this network. Together, its IPv4 prefixes cover 13,824 addresses, with overlapping prefixes counted once. In the paths the collectors record, it has 23 upstream neighbours (transit providers or peers) and 8 downstream neighbours (customers or networks it carries). Its most visible upstreams are RETN Limited (AS9002), Voxility LLP (AS3223), and Arelion Sweden AB (AS1299). AS51248 was assigned by RIPE NCC, and its registration country is Czechia.

Source: RIPEstat (RIPE NCC), RIS route collectors. Read on October 16, 2026 at 10:56 PM UTC. This page is refreshed at most every 12 hours.

Go further

The trace goes to 5.43.224.1, the first address of 5.43.224.0/21. 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 (20 prefixes)

PrefixAddresses
5.43.224.0/212,048
13.143.234.0/24256
45.10.191.0/24256
45.129.142.0/24256
85.137.25.0/24256
85.137.26.0/24256
89.125.237.0/24256
91.209.77.0/24256
135.106.134.0/23512
153.52.69.0/24256
158.255.32.0/212,048
158.255.39.0/24256
176.74.216.0/212,048
185.8.56.0/221,024
188.124.56.0/212,048
193.161.84.0/221,024
194.87.52.0/24256
194.87.126.0/24256
195.133.35.0/24256
212.192.210.0/24256

IPv6 prefixes (5 prefixes)

Prefix
2a03:1840::/48
2a03:1840:1::/48
2a03:1840:2::/48
2a03:1840:3::/48
2a10:9687::/32

Neighbours

Upstreams (transit or peers) (23)

ASNetworkVisibility
AS9002RETN Limited887
AS3223Voxility LLP820
AS1299Arelion Sweden AB477
AS3257GTT Communications Inc.344
AS174Cogent Communications, LLC315
AS6939Hurricane Electric LLC255
AS25091IP-Max SA57
AS8218Zayo Infrastructure France SA21
AS14840BR.Digital Telecom19
AS49434FBW NETWORKS SAS19
AS50629LWLcom GmbH18
AS61049Exascale Ltd17
AS1764Next Layer Telekommunikationsdienstleistungs- und Beratungs GmbH16
AS33891Core-Backbone GmbH15
AS34927iFog GmbH14
AS9198JSC Kazakhtelecom9
AS286GTT Communications Inc.7
AS21030Cluster LLC7
AS4455IX Reach Ltd6
AS6204INTERKVM HOST SRL6
AS6663Euroweb Romania S.R.L.6
AS137409GSL Networks Pty LTD2
AS263444Open X Tecnologia Ltda1

Downstreams (customers) (8)

ASNetworkVisibility
AS62212SmartApe OU1,905
AS215305Mastersoft S.R.L.318
AS216024ALEKSEI FEDOROV PR KRUSEVAC261
AS199669Okay-Telecom Ltd.250
AS3223Voxility LLP15
AS174Cogent Communications, LLC3
AS202984Chernyshov Aleksandr Aleksandrovich3
AS3257GTT Communications Inc.2

14 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.