AS33651 — CMCS - Comcast Cable Communications, LLC

AS33651 announces 188 IPv4 prefixes covering 2,267,136 addresses and 171 IPv6 prefixes.

About this network

CMCS is the AS handle for Comcast Cable Communications, LLC.

What it's used for

• The address space carries residential cable internet services, evidenced by reverse DNS entries like c-24-4-128-0.hsd1.ca.comcast.net and netnames such as BAYAREA-CPE-23 and SFBA-CPE-49.
• With 2,268,160 IPv4 addresses announced across 189 prefixes and 143 observed neighbours, the high address-to-neighbour ratio indicates a large access/eyeball network rather than a transit provider.

Notable

• Registrants consistently identify as Comcast Cable Communications, LLC or its subsidiaries (e.g., Comcast Cable Communications, Inc., Comcast Cable Communications Holdings, Inc), aligning with the announcer.
• The address inventory is finely subdivided into regional blocks, with netnames referencing specific markets like BAYAREA and SFBA, reflecting site-by-site segmentation of the corporate estate.

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

Announced prefixes

• 23.24.192.0/19
• 24.4.0.0/15
• 24.6.0.0/16
• 24.7.0.0/17
• 24.104.72.0/23
• 24.104.138.0/23
• 24.104.150.0/24
• 24.124.158.0/23
• 24.130.0.0/16
• 50.76.32.0/19
• 50.78.96.0/20
• 50.79.32.0/20
• 50.79.208.0/21
• 50.145.55.0/24
• 50.176.128.0/19
• 50.189.64.0/18
• 50.191.160.0/19
• 50.193.0.0/18
• 50.196.128.0/18
• 50.197.128.0/18
• 50.200.170.0/24
• 50.201.8.0/23
• 50.201.171.0/24
• 50.204.119.0/24
• 50.204.137.0/24
• 50.205.226.0/24
• 50.206.118.0/24
• 50.206.120.0/23
• 50.206.219.0/24
• 50.207.182.0/24
• 50.207.190.0/24
• 50.207.216.0/24
• 50.208.32.0/19
• 50.209.128.0/18
• 50.211.192.0/19
• 50.213.0.0/18
• 50.215.0.0/19
• 50.216.23.0/24
• 50.216.212.0/24
• 50.218.46.0/24
• 50.219.139.0/24
• 50.222.26.0/24
• 50.222.50.0/24
• 50.222.102.0/24
• 50.224.7.0/24
• 50.227.120.0/24
• 50.227.186.0/24
• 50.228.130.0/24
• 50.229.212.0/24
• 50.230.66.0/24
• 50.231.143.0/24
• 50.232.196.0/24
• 50.233.45.0/24
• 50.234.130.0/24
• 50.235.20.0/23
• 50.235.233.0/24
• 50.236.66.0/24
• 50.239.184.0/24
• 50.240.192.0/19
• 50.242.64.0/18
• 50.247.64.0/18
• 50.250.192.0/18
• 50.254.128.0/19
• 50.255.0.0/18
• 64.84.96.0/21
• 64.84.120.0/21
• 67.160.192.0/18
• 67.161.0.0/18
• 67.161.64.0/20
• 67.164.0.0/17
• 67.169.0.0/17
• 67.169.128.0/18
• 67.170.192.0/18
• 67.174.192.0/18
• 67.180.0.0/16
• 67.188.0.0/16
• 68.85.28.0/24
• 68.85.57.0/24
• 68.85.86.0/24
• 68.85.100.0/22
• 68.85.154.0/23
• 68.85.190.0/23
• 68.85.216.0/23
• 68.86.62.0/24
• 68.86.142.0/23
• 68.86.248.0/23
• 68.87.76.0/24
• 68.87.192.0/21
• 68.87.226.0/23
• 68.87.251.0/24
• 68.87.252.0/24
• 69.91.146.0/24
• 69.139.198.0/23
• 69.181.0.0/16
• 69.241.74.0/23
• 69.241.90.0/24
• 69.252.70.0/24
• 69.252.96.0/23
• 69.252.197.0/24
• 69.252.255.0/24

and 259 more.

Upstream networks

• AS7922 Comcast Cable Communications, LLC
• AS3356 Level 3 Parent, LLC

Downstream networks

• AS1226 California Department of Technology
• AS46341 California Public Utilities Commission
• AS10309 County of Marin
• AS6379 A-Link Network Services, Inc.
• AS14203 Juniper Networks, Inc.
• AS25875 FriendFinder Networks Inc
• AS20066 Supermicro Computer
• AS22700 University of San Francisco
• AS46826 Razzo Link, Inc.
• AS54113 Fastly, Inc.
• AS32537 Xilinx Incorporated
• AS32504 Intelletrace
• AS23154 Sanmina-SCI Corporation
• AS395976 Comcast Cable Communications, LLC
• AS36040 Google LLC
• AS63435 County of Monterey
• AS55059 Microwave Power Products, Inc.
• AS11328 Bio-Rad Laboratories, Inc.
• AS6099 Alameda County Office of Education
• AS46186 Gilead Sciences
• AS29878 Community Hospital of the Monterey Peninsula
• AS35928 BECKMAN COULTER, INC.
• AS19126 KIZA
• AS395011 City and County of San Francisco
• AS17117 RITSnet, Inc.

Adjacent networks

• AS7922 Comcast Cable Communications, LLC
• AS1226 California Department of Technology
• AS3356 Level 3 Parent, LLC
• AS46341 California Public Utilities Commission
• AS10309 County of Marin
• AS6379 A-Link Network Services, Inc.
• AS14203 Juniper Networks, Inc.
• AS6099 Alameda County Office of Education
• AS25875 FriendFinder Networks Inc
• AS20066 Supermicro Computer
• AS22700 University of San Francisco
• AS55064 Arista Networks, Inc.
• AS46826 Razzo Link, Inc.
• AS54113 Fastly, Inc.
• AS32537 Xilinx Incorporated
• AS32504 Intelletrace
• AS36040 Google LLC
• AS23154 Sanmina-SCI Corporation
• AS395976 Comcast Cable Communications, LLC
• AS63435 County of Monterey
• AS55059 Microwave Power Products, Inc.
• AS11328 Bio-Rad Laboratories, Inc.
• AS46186 Gilead Sciences
• AS29878 Community Hospital of the Monterey Peninsula
• AS35928 BECKMAN COULTER, INC.

Routing security

• RPKI: 280 valid, 5 invalid and 11 not-found announcements; 4,888 ROAs.
• ASPA: none published.
• IRR: 13% of announcements registered; 98 route objects.
• Listed in as-sets: AS-17117IMPORT, AS-COMCAST-IBONE, AS-COMCAST-RANS, AS7922:AS-COMCAST-RANS.