Autonomous system
AS33667 CMCS
Unclassified ARIN Cable/DSL/ISP
Summary
Comcast
residential cable isp us
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-67-181-127-255.hsd1.ca.comcast.netand netnames such asCENTRALCALI-CPE-17andSACRAMENTO-9. - With 996,352 IPv4 addresses announced across 181 prefixes and 137 observed neighbours, the high address-to-neighbour ratio indicates a large-scale access network rather than a transit provider.
Notable
- All sampled registrants align with the announcer, consistently listing Comcast Cable Communications, LLC or Comcast Cable Communications.
- The inventory is finely subdivided into regional blocks, including specific Central California and Sacramento designations, 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. Source, and how to suggest an edit.
Interconnection
Peering at a glance
Internet exchanges
No exchange port on file. Many exchanges publish no participant list, so this is not proof of absence.
Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-28, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.
Address space
Summary
IPv4 183 prefixes · 1000K addresses IPv6 133 prefixes
| Country | Name | Prefixes |
|---|---|---|
| US | United States of America | 316 |
Registry
Allocation record
- Registry
- ARIN
- Handle
AS33667- Registry name
- CMCS
- Registrant
- Comcast Cable Communications, LLC
- Abuse contact
- abuse@comcast.net
- Registered
- 2005-02-16
- Last changed
- 2021-01-25
- Allocation
- assigned
Declared
PeeringDB profile
- Name
- Comcast - Central California
- Network type
- Cable/DSL/ISP
- Scope
- Regional
- Traffic ratio
- Not Disclosed
- Peering policy
- Restrictive
- Facilities
- 1 facilities
PeeringDB records are maintained by the network operator and are not independently verified. Treat them as a statement of intent rather than of fact. For the observed and recorded view, see peering, which lists the exchanges Packet Clearing House has a port on file for.
Routing security
RPKI and IRR
- RPKI
- 82% valid · 101 valid, 16 with no ROA 6 RPKI-invalid
- ROAs
- 486 authorising AS33667
- ASPA
- no ASPA record
- IRR
- 59% registered · 72 of 123 announcements 17 other origin
- Route objects
- 210 naming AS33667
Reputation
Classification and threat
Unclassified Not in the curated lists. Most of the ~80,000 allocated ASNs are not.
Spamhaus DROP
Not on ASN-DROP The network as a whole is not listed.
No DROP prefixes None of its announced space is on the DROP prefix list.
Spamhaus DROP ("Don't Route Or Peer") lists space and networks run by, or hijacked for, spam and cybercrime operations: 448 networks and 1,849 prefixes, as published 2026-10-29. A short, high-confidence list, so a match is worth taking seriously, and absence from it says little on its own.
FBI IC3
No IC3 indicators Nothing from the FBI IC3 feed.
IC3 threat data is alpha. Absence of an indicator is not evidence of good behaviour, only of absence from this one feed.
Elsewhere