AS21508 — COMCAST-21508

AS21508 announces 141 IPv4 prefixes covering 689,152 addresses and 71 IPv6 prefixes.

About this network

COMCAST-21508 is operated by Comcast Cable Communications, LLC.

What it's used for

• The address space carries residential and business cable internet services, evidenced by reverse DNS entries like c-71-62-127-255.hsd1.va.comcast.net and c-50-189-239-254.unallocated.comcastbusiness.net.
• With 689,152 IPv4 addresses announced against 47 observed neighbours, the high address-to-neighbour ratio indicates an access/eyeball network rather than a transit provider.

Notable

• Registrants are consistent with the announcer, including Comcast Cable Communications Holdings, Inc, Comcast Cable Communications, LLC, and Comcast Cable Communications, Inc.
• One prefix, 141.104.0.0/16, is registered to the Virginia Department of Education with netname VAK12ED-NET, which does not fit the typical Comcast residential pattern.
• The inventory includes 141 IPv4 prefixes and 71 IPv6 prefixes, with the largest blocks being /16s such as 71.62.0.0/16 and 174.179.0.0/16.

This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy.

Announced prefixes

• 23.25.96.0/19
• 23.25.186.0/23
• 23.31.96.0/20
• 24.124.151.0/24
• 24.124.162.0/23
• 24.124.248.0/21
• 24.131.0.0/20
• 50.73.8.0/22
• 50.73.224.0/20
• 50.77.72.0/21
• 50.78.232.0/21
• 50.184.128.0/19
• 50.186.32.0/19
• 50.189.192.0/18
• 50.193.246.0/23
• 50.199.16.0/20
• 50.204.101.0/24
• 50.205.217.0/24
• 50.210.0.0/20
• 50.211.32.0/19
• 50.215.32.0/19
• 50.216.229.0/24
• 50.217.1.0/24
• 50.217.207.0/24
• 50.218.47.0/24
• 50.228.113.0/24
• 50.229.113.0/24
• 50.229.114.0/24
• 50.235.34.0/24
• 50.240.80.0/20
• 50.242.32.0/19
• 50.245.224.0/19
• 50.251.112.0/20
• 50.253.208.0/20
• 64.139.66.0/24
• 64.139.70.0/24
• 64.139.79.0/24
• 64.139.90.0/24
• 66.208.224.0/23
• 66.208.230.0/24
• 66.208.234.0/24
• 67.163.96.0/19
• 67.166.160.0/19
• 67.172.192.0/19
• 67.174.64.0/20
• 67.187.0.0/19
• 68.85.70.0/23
• 68.85.214.0/24
• 68.85.226.0/24
• 68.86.14.0/24
• 68.86.24.0/24
• 68.86.124.0/22
• 68.86.172.0/22
• 68.86.200.0/24
• 68.87.3.0/24
• 69.139.165.0/24
• 69.139.186.0/24
• 69.139.206.0/24
• 69.139.223.0/24
• 69.241.48.0/23
• 69.241.85.0/24
• 69.243.208.0/20
• 69.244.224.0/20
• 69.252.18.0/23
• 70.88.24.0/23
• 70.88.164.0/24
• 70.88.168.0/23
• 70.88.184.0/21
• 70.89.232.0/21
• 70.91.162.0/24
• 71.24.32.0/19
• 71.56.160.0/19
• 71.57.192.0/19
• 71.62.0.0/16
• 71.63.0.0/17
• 71.197.0.0/20
• 71.206.128.0/18
• 71.207.128.0/19
• 74.92.186.0/23
• 74.92.255.0/24
• 74.93.116.0/22
• 74.94.208.0/21
• 74.95.96.0/22
• 75.75.0.0/18
• 75.75.64.0/21
• 75.75.80.0/20
• 75.75.96.0/19
• 75.144.34.0/23
• 75.145.196.0/22
• 75.145.204.0/22
• 75.145.240.0/21
• 75.146.16.0/20
• 75.146.87.0/24
• 75.150.48.0/20
• 76.26.64.0/19
• 76.27.160.0/19
• 76.104.0.0/17
• 76.111.176.0/20
• 76.120.192.0/18
• 76.123.0.0/18

and 112 more.

Upstream networks

• AS7922 Comcast Cable Communications, LLC

Downstream networks

• AS40641 MGW Telephone Company, Inc.
• AS15297 EPLUS, Inc.
• AS400114 Apogee Telecom Inc.
• AS18773 County of Henrico
• AS396083 Framatome Inc.
• AS15173 Newmarket Corporation
• AS2134 Santander Global Technology and Operations, S.L.
• AS13335 Cloudflare, Inc.
• AS54113 Fastly, Inc.
• AS19923 Shenandoah University
• AS36364 Mary Washington Hospital, Inc.
• AS54219 Matthews International Corporation
• AS36040 Google LLC
• AS32540 HP Hood
• AS54883 City of Richmond, Virginia
• AS399099 petersburg city public schools
• AS402549 Terraservers
• AS11739 Digital Fortress, Inc.
• AS395772 Augusta Health Care, Inc
• AS36244 Shenandoah Valley Electric Cooperative
• AS14583 Virginia Information Technologies Agency (VITA)
• AS394276 TurnAround Factor, Inc.
• AS27326 VCU HEALTH SYSTEM AUTHORITY
• AS394058 Telos Corporation
• AS397039 WorldStrides

Adjacent networks

• AS7922 Comcast Cable Communications, LLC
• AS40641 MGW Telephone Company, Inc.
• AS15297 EPLUS, Inc.
• AS400114 Apogee Telecom Inc.
• AS18773 County of Henrico
• AS396083 Framatome Inc.
• AS15173 Newmarket Corporation
• AS2134 Santander Global Technology and Operations, S.L.
• AS13335 Cloudflare, Inc.
• AS54113 Fastly, Inc.
• AS19923 Shenandoah University
• AS36364 Mary Washington Hospital, Inc.
• AS54219 Matthews International Corporation
• AS36040 Google LLC
• AS54883 City of Richmond, Virginia
• AS399938 Berkshire Hathaway Energy Company
• AS399099 petersburg city public schools
• AS32540 HP Hood
• AS402549 Terraservers
• AS395772 Augusta Health Care, Inc
• AS11739 Digital Fortress, Inc.
• AS36244 Shenandoah Valley Electric Cooperative
• AS14583 Virginia Information Technologies Agency (VITA)
• AS394276 TurnAround Factor, Inc.
• AS27326 VCU HEALTH SYSTEM AUTHORITY