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Autonomous System

AS209 · CenturyLink Communications, LLC

Overview

AS209 is announced on the Internet: RIPE RIS route collectors currently see 1,587 IPv4 prefixes and 32 IPv6 prefixes originated by this network. Together, its IPv4 prefixes cover 19,845,632 addresses, with overlapping prefixes counted once. In the paths the collectors record, it has 1 upstream neighbour (transit providers or peers) and 291 downstream neighbours (customers or networks it carries). Its most visible upstream is Level 3 Parent, LLC (AS3356). AS209 was assigned by ARIN, and its registration country is United States.

Source: RIPEstat (RIPE NCC), RIS route collectors. Read on October 16, 2026 at 6:59 PM UTC. This page is refreshed at most every 12 hours.

Go further

The trace goes to 65.128.0.1, the first address of 65.128.0.0/11. 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 (1,587 prefixes)

PrefixAddresses
8.15.5.0/24256
24.223.60.0/24256
24.223.74.0/23512
52.119.16.0/204,096
52.119.26.0/24256
52.119.28.0/24256
63.144.0.0/121,048,576
63.152.0.0/1665,536
63.153.0.0/1816,384
63.153.128.0/1732,768
63.155.0.0/1665,536
63.155.0.0/198,192
63.224.0.0/121,048,576
63.224.0.0/212,048
63.224.10.0/23512
63.224.16.0/212,048
63.224.25.0/24256
63.224.26.0/23512
63.224.32.0/212,048
63.224.40.0/221,024
63.224.44.0/24256
63.224.46.0/23512
63.224.48.0/24256
63.224.51.0/24256
63.224.54.0/23512
63.224.56.0/221,024
63.224.62.0/24256
63.224.64.0/24256
63.224.68.0/23512
63.224.70.0/24256
63.224.79.0/24256
63.224.84.0/23512
63.224.86.0/24256
63.224.89.0/24256
63.224.100.0/221,024
63.224.128.0/221,024
63.224.132.0/24256
63.224.134.0/23512
63.224.136.0/23512
63.224.140.0/23512
63.224.145.0/24256
63.224.146.0/23512
63.224.148.0/23512
63.224.156.0/221,024
63.224.180.0/221,024
63.224.184.0/221,024
63.224.188.0/24256
63.224.190.0/24256
63.224.194.0/23512
63.224.200.0/212,048
63.224.208.0/221,024
63.224.214.0/23512
63.224.216.0/23512
63.224.218.0/24256
63.224.220.0/221,024
63.224.226.0/23512
63.224.231.0/24256
63.224.232.0/212,048
63.224.240.0/23512
63.224.248.0/212,048
63.225.0.0/24256
63.225.4.0/221,024
63.225.8.0/24256
63.225.18.0/23512
63.225.28.0/24256
63.225.29.0/24256
63.225.32.0/24256
63.225.37.0/24256
63.225.38.0/23512
63.225.41.0/24256
63.225.42.0/23512
63.225.44.0/24256
63.225.62.0/24256
63.225.72.0/23512
63.225.72.0/24256
63.225.73.0/24256
63.225.76.0/221,024
63.225.80.0/204,096
63.225.96.0/23512
63.225.98.0/24256
63.225.100.0/221,024
63.225.104.0/212,048
63.225.112.0/204,096
63.225.124.0/221,024
63.225.131.0/24256
63.225.132.0/23512
63.225.138.0/23512
63.225.140.0/23512
63.225.144.0/212,048
63.225.152.0/221,024
63.225.161.0/24256
63.225.162.0/23512
63.225.164.0/221,024
63.225.168.0/212,048
63.225.172.0/221,024
63.225.176.0/204,096
63.225.192.0/204,096
63.225.208.0/212,048
63.225.218.0/23512
63.225.220.0/221,024

Showing the first 100 of 1,587, in address order. Complete list on RIPEstat

IPv6 prefixes (32 prefixes)

Prefix
2001:428::/32
2001:460::/32
2602::/24
2604:8c0::/32
2606:5000::/32
2606:5000::/39
2606:5000:200::/39
2606:5000:400::/39
2606:5000:600::/39
2606:5000:800::/39
2606:5000:a00::/39
2606:5000:e00::/39
2606:5000:1200::/39
2606:5000:1600::/39
2606:5000:1800::/39
2606:5000:1a00::/39
2606:5000:2000::/39
2606:5000:2400::/39
2606:5000:2600::/39
2606:5000:2e00::/39
2606:5000:3000::/39
2606:5000:3400::/39
2606:5000:3600::/39
2606:5000:3800::/39
2606:5000:3a00::/39
2606:5000:4000::/39
2606:5000:4200::/39
2606:5000:4400::/39
2606:5000:4a00::/39
2606:5000:4c00::/39
2606:5000:5a00::/39
2620:13d:2060::/46

Neighbours

Upstreams (transit or peers) (1)

ASNetworkVisibility
AS3356Level 3 Parent, LLC62,335

Downstreams (customers) (291)

ASNetworkVisibility
AS22561CenturyLink Communications, LLC3,367
AS6223CenturyLink Communications, LLC2,352
AS18530Isomedia, Inc.1,441
AS297National Aeronautics and Space Administration1,419
AS4297CenturyLink Communications, LLC1,361
AS6224CenturyLink Communications, LLC1,191
AS30221T3 Communications, Inc.789
AS32083Omnispring, LLC787
AS396908Laurens Technologies Internet Services588
AS11857Money Services, Inc.508
AS19800-505
AS46182-504
AS26848-503
AS3561-456
AS4296-395
AS3909-366
AS7359-352
AS7743-346
AS4015-344
AS11985-344
AS62645-343
AS13866Computer Country326
AS397045-304
AS13684-303
AS400008-296
AS10695-276
AS27013-274
AS32904-271
AS14921-270
AS396402MultiCare Health System269

The 30 most visible of 291.

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.