Country
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ASN LANDING PAGE
AS21508
COMCAST-21508 - Comcast Cable Communications
Last updated · Apr 4, 2026
Total prefixes
84
IPv4 prefixes
18
IPv6 prefixes
66
ASN summary
How to read the scale of AS21508
COMCAST-21508 - Comcast Cable Communications currently shows 84 prefixes and 41 upstream, downstream, or peer relationships. Larger prefix inventories often indicate broader network footprint, but they should still be read together with country and peering context.
When is an ASN page most useful?
ASN landing pages are more useful than a single IP page when you want cloud provider attribution, routing research, infrastructure comparison, or network topology analysis at the organization level.
How should you read the country, organization, and role of AS21508?
COMCAST-21508 - Comcast Cable Communications is currently associated with an unknown region. Country data is only a starting point; the more important signals are the organization name, website, prefix volume, and peering relationships that reveal whether the network behaves like a cloud platform, ISP, CDN, or enterprise backbone.
What should you inspect next after the AS21508 page?
This page is currently showing live ASN data that can be used for peer, prefix, and network scale analysis. The most useful next step is usually to return to a related IP landing page, then compare that concrete address with this ASN profile and with broader topic pages for routing, cloud attribution, or WHOIS ownership analysis.
Search intents this ASN page helps cover
AS21508 ASN lookupAS21508 BGPAS21508 peersAS21508 prefixesAS21508 upstreamsCOMCAST-21508 - Comcast Cable Communications ASN
Upstreams
Detailed data for this ASN is not available right now.
Downstreams
AS13335
AS13335
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AS400114
AS400114
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AS396083
AS396083
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AS36364
AS36364
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AS40641
AS40641
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AS32540
AS32540
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AS54883
AS54883
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AS399938
AS399938
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AS36040
AS36040
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AS54219
AS54219
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AS15173
AS15173
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AS11739
AS11739
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AS15297
AS15297
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AS399099
AS399099
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AS394276
AS394276
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AS14583
AS14583
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AS36244
AS36244
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AS395772
AS395772
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AS19923
AS19923
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AS397039
AS397039
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AS393591
AS393591
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AS394058
AS394058
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AS397483
AS397483
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AS63468
AS63468
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AS393613
AS393613
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AS18773
AS18773
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AS10794
AS10794
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AS19404
AS19404
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AS46643
AS46643
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AS396452
AS396452
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AS23209
AS23209
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AS11679
AS11679
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AS62971
AS62971
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AS395527
AS395527
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AS399607
AS399607
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AS17381
AS17381
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AS30299
AS30299
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AS397190
AS397190
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AS54391
AS54391
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AS22274
AS22274
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Peers
Prefix inventory
| Prefix | Name | Country |
|---|---|---|
| 141.104.0.0/16 | AS21508 | — |
| 157.240.147.0/24 | AS21508 | — |
| 157.240.148.0/24 | AS21508 | — |
| 173.242.174.0/24 | AS21508 | — |
| 198.90.112.0/22 | AS21508 | — |
| 2001:559:220::/48 | AS21508 | — |
| 2001:559:243::/48 | AS21508 | — |
| 2001:559:280::/48 | AS21508 | — |
| 2001:559:37d::/48 | AS21508 | — |
| 2001:559:3ac::/48 | AS21508 | — |
| 2001:559:3b9::/48 | AS21508 | — |
| 2001:559:3c8::/48 | AS21508 | — |
| 2001:559:40a::/48 | AS21508 | — |
| 2001:559:49a::/48 | AS21508 | — |
| 2001:559:49b::/48 | AS21508 | — |
| 2001:559:53c::/48 | AS21508 | — |
| 2001:559:5c9::/48 | AS21508 | — |
| 2001:559:5db::/48 | AS21508 | — |
| 2001:559:72b::/48 | AS21508 | — |
| 2001:559:73c::/48 | AS21508 | — |
| 2001:559:788::/48 | AS21508 | — |
| 2001:559:78a::/48 | AS21508 | — |
| 2001:559:79d::/48 | AS21508 | — |
| 2001:559:79e::/48 | AS21508 | — |
| 2001:559:7a7::/48 | AS21508 | — |
| 2001:559:7db::/48 | AS21508 | — |
| 2001:559:804c::/48 | AS21508 | — |
| 2001:559:81bf::/48 | AS21508 | — |
| 2001:559:81d7::/48 | AS21508 | — |
| 2001:559:81d8::/48 | AS21508 | — |
| 2001:559:8201::/48 | AS21508 | — |
| 2001:559:82fd::/48 | AS21508 | — |
| 2001:559:833e::/48 | AS21508 | — |
| 2001:559:8416::/48 | AS21508 | — |
| 2001:559:841c::/48 | AS21508 | — |
| 2001:559:8445::/48 | AS21508 | — |
| 2001:559:84a7::/48 | AS21508 | — |
| 2001:559:8535::/48 | AS21508 | — |
| 2001:559:85c1::/48 | AS21508 | — |
| 2001:559:85ff::/48 | AS21508 | — |
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Related lookups and next steps
WHOIS vs ASN Ownership Guide
Continue from this ASN into the differences between WHOIS ownership and ASN ownership.
Routing Troubleshooting and Network Analysis
Continue from this ASN into route troubleshooting and network analysis.
Cloud Network and ASN Comparison
Useful when you want to compare this ASN against larger cloud and edge networks.
WHOIS and IP Ownership Guide
Continue from the ASN page into WHOIS and ownership verification.
Frequently asked questions about this ASN page
What does AS21508 represent?
AS21508 is an autonomous system number used to identify an independently operated network. The current page associates it with COMCAST-21508 - Comcast Cable Communications in an unknown region, which helps determine whether it behaves like a cloud provider, ISP, CDN, or enterprise backbone.
What are peers, upstreams, and prefixes useful for on the AS21508 page?
They help explain the scale, interconnection depth, and route structure of AS21508. Richer peering and upstream data often indicate broader network reach, but they should still be interpreted together with prefixes and related IP landing pages.
What should you do after reviewing AS21508?
The best next step is usually to return to a concrete IP landing page to see how a specific address maps into AS21508, then continue into cloud, WHOIS, or routing topic pages to understand the network in a broader context.
Related topics
WHOIS vs ASN Ownership Guide
Understand why WHOIS ownership and ASN ownership can differ, and how to combine both when deciding who really owns or operates an IP.
WHOIS and IP Ownership Guide
Use WHOIS, ASN, prefixes, and organization data to determine who ultimately owns an IP, range, or resolved domain target.
BGP and ASN Basics Guide
Learn what ASN, BGP routes, prefixes, upstreams, downstreams, and peers mean, then explore real ASN pages.
Cloud Network and ASN Comparison
Compare large cloud and edge networks such as Google, Cloudflare, Microsoft, and Amazon through their ASN landing pages.