AS33657 — CMCS - Comcast Cable Communications, LLC

AS33657 announces 179 IPv4 prefixes covering 1,553,408 addresses and 229 IPv6 prefixes.

About this network

The AS handle CMCS is held by Comcast Cable Communications, LLC.

What it's used for

• The address space carries residential cable internet services, evidenced by reverse DNS entries like c-68-33-191-254.hsd1.va.comcast.net and c-76-100-64-0.hsd1.md.comcast.net.
• The inventory includes 1,553,408 IPv4 addresses and 233 IPv6 prefixes, with 179 IPv4 prefixes in inventory.
• With 133 observed neighbours, the high address-to-neighbour ratio indicates this is an access/eyeball network rather than a transit provider.

Notable

• Registrants vary slightly across prefixes, including Comcast Cable Communications, LLC, Comcast Cable Communications, Inc., Comcast Cable Communications Holdings, Inc, and Comcast Cable Communications, IP Services, reflecting corporate restructuring or historical acquisitions.
• The address inventory is finely subdivided into 179 IPv4 prefixes, consistent with a large-scale residential ISP managing distinct regional or service segments.

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

Announced prefixes

• 23.24.96.0/19
• 23.25.188.0/22
• 23.30.0.0/19
• 23.31.192.0/19
• 24.124.152.0/23
• 24.124.176.0/20
• 24.126.0.0/17
• 50.76.0.0/19
• 50.78.64.0/20
• 50.79.0.0/20
• 50.186.128.0/17
• 50.190.192.0/18
• 50.193.128.0/19
• 50.195.64.0/19
• 50.197.0.0/19
• 50.198.128.0/19
• 50.201.252.0/24
• 50.202.117.0/24
• 50.202.155.0/24
• 50.203.251.0/24
• 50.204.116.0/24
• 50.204.128.0/24
• 50.205.74.0/24
• 50.207.162.0/24
• 50.210.128.0/19
• 50.211.128.0/18
• 50.213.192.0/18
• 50.216.214.0/24
• 50.219.87.0/24
• 50.223.158.0/23
• 50.224.212.0/24
• 50.232.109.0/24
• 50.232.173.0/24
• 50.232.184.0/24
• 50.235.98.0/24
• 50.235.236.0/24
• 50.236.38.0/24
• 50.236.234.0/24
• 50.238.163.0/24
• 50.241.128.0/19
• 50.242.176.0/20
• 50.242.192.0/18
• 50.246.64.0/18
• 50.249.0.0/18
• 50.253.0.0/18
• 67.162.224.0/19
• 68.33.0.0/16
• 68.83.208.0/20
• 68.84.0.0/20
• 68.84.128.0/20
• 68.85.4.0/24
• 68.85.31.0/24
• 68.85.61.0/24
• 68.85.67.0/24
• 68.85.80.0/23
• 68.85.112.0/22
• 68.85.130.0/24
• 68.85.133.0/24
• 68.85.134.0/24
• 68.85.138.0/23
• 68.85.147.0/24
• 68.85.170.0/24
• 68.85.175.0/24
• 68.85.209.0/24
• 68.86.12.0/23
• 68.86.33.0/24
• 68.86.204.0/23
• 68.86.252.0/22
• 68.87.73.0/24
• 68.87.128.0/20
• 68.87.168.0/23
• 69.67.80.0/20
• 69.136.224.0/20
• 69.137.32.0/19
• 69.137.144.0/20
• 69.137.224.0/20
• 69.138.0.0/19
• 69.138.64.0/19
• 69.138.160.0/19
• 69.138.192.0/18
• 69.139.174.0/23
• 69.139.214.0/23
• 69.139.246.0/24
• 69.140.0.0/16
• 69.143.0.0/16
• 69.241.12.0/24
• 69.241.110.0/23
• 69.243.0.0/17
• 69.244.64.0/19
• 69.250.0.0/15
• 69.252.32.0/22
• 69.252.56.0/24
• 69.252.67.0/24
• 69.252.98.0/23
• 69.252.221.0/24
• 69.252.245.0/24
• 69.255.0.0/16
• 70.88.112.0/21
• 70.88.128.0/19
• 70.88.224.0/20

and 308 more.

Upstream networks

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

Downstream networks

• AS27016 United States Nuclear Regulatory Commission
• AS394077 Lifebridge Health, Inc.
• AS11790 Random House, Inc.
• AS32073 Montgomery County Public Schools
• AS53373 Mathematica, Inc.
• AS22101 Cyber Point International, LLC
• AS17190 Washington Metropolitan Area Transit Authority
• AS2703 DATAPR-3
• AS16463 Data Processing Solutions, Inc.
• AS25716 Trane Technologies Company LLC
• AS11951 Medical Computer Systems
• AS19320 Flextronics International USA, Inc.
• AS20137 USAGM
• AS400902 Gaylord National Resort & Convention Center
• AS40410 FRIT
• AS19936 Gordon Food Service
• AS53350 Embassy of Hungary
• AS2384 Architect of the Capitol
• AS40954 JM Family Enterprises Inc.
• AS32291 ANNE ARUNDEL MEDICAL CENTER
• AS26522 Stevenson University
• AS16881 Prall, Inc., David C
• AS398820 Eagle Alliance
• AS10918 Accurant Cloud Services LLC
• AS13511 Univision Communications Inc.

Adjacent networks

• AS7922 Comcast Cable Communications, LLC
• AS3356 Level 3 Parent, LLC
• AS27016 United States Nuclear Regulatory Commission
• AS394077 Lifebridge Health, Inc.
• AS11790 Random House, Inc.
• AS32073 Montgomery County Public Schools
• AS53373 Mathematica, Inc.
• AS22101 Cyber Point International, LLC
• AS17190 Washington Metropolitan Area Transit Authority
• AS16463 Data Processing Solutions, Inc.
• AS2703 DATAPR-3
• AS25716 Trane Technologies Company LLC
• AS11951 Medical Computer Systems
• AS19320 Flextronics International USA, Inc.
• AS20137 USAGM
• AS400902 Gaylord National Resort & Convention Center
• AS40410 FRIT
• AS19936 Gordon Food Service
• AS53350 Embassy of Hungary
• AS2384 Architect of the Capitol
• AS40954 JM Family Enterprises Inc.
• AS32291 ANNE ARUNDEL MEDICAL CENTER
• AS26522 Stevenson University
• AS16881 Prall, Inc., David C
• AS398820 Eagle Alliance

Routing security

• RPKI: 260 valid, 2 invalid and 5 not-found announcements; 702 ROAs.
• ASPA: none published.
• IRR: 0% of announcements registered; 27 route objects.
• Listed in as-sets: AS-COMCAST-IBONE, AS-COMCAST-RANS, AS7922:AS-COMCAST-RANS.