Autonomous system
AS4991 COGENT-4991-4994
Unclassified ARIN
Summary
Cogent Communications
transit isp legacy
AS4991 belongs to Cogent Communications, LLC, one of the largest IP transit carriers in the world. It is registered under the ARIN handle COGENT-4991-4994, a single record covering a small run of consecutive AS numbers Cogent holds alongside its flagship AS174.
What it's used for
Cogent operates a global backbone selling wholesale IP transit, dedicated internet access, and Ethernet transport, largely to carriers, hosting providers, content networks, and businesses in multi-tenant office buildings. AS4991 is a secondary AS in that estate rather than the backbone itself: the ~16k addresses under it are customer and infrastructure assignments carried across the same network.
Notable
Cogent's commercial identity is built on volume and price. It has long been among the most widely connected networks by peer count, which is why its routes appear near the top of transit-path rankings and why Cogent shows up repeatedly in the industry's peering disputes with other large networks.
Large carriers rarely announce everything from one AS number. Acquisitions, legacy customer blocks, and regional builds accumulate spare ASNs, and consolidating them under one ARIN handle (as COGENT-4991-4994 does) is a common way to keep the registry tidy.
Interesting
The address space and AS numbers Cogent holds today are in part inherited: the company grew heavily through acquisition of earlier internet businesses, so its registry footprint is older than the Cogent brand itself.
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.
Transit providers
1 upstream, 0 downstream and 1 adjacent networks observed; most-used upstreams first.
| AS | Network | Paths seen |
|---|---|---|
| AS54054 | Deteque | 58 |
Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-24, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.
Address space
Summary
IPv4 1 prefixes · 16.38K addresses IPv6 0 prefixes
| Country | Name | Prefixes |
|---|---|---|
| US | United States of America | 1 |
Registry
Allocation record
- Registry
- ARIN
- Handle
AS4991- Registry name
- COGENT-4991-4994
- Registrant
- Cogent Communications, LLC
- Abuse contact
- abuse@cogentco.com
- Registered
- 1995-05-31
- Last changed
- 2025-09-23
- Allocation
- assigned
Routing security
RPKI and IRR
- RPKI
- 0% valid · 0 valid, 1 with no ROA
- ROAs
- 0 authorising AS4991
- ASPA
- no ASPA record
- IRR
- 0% registered · 0 of 1 announcements 1 other origin
- Route objects
- 0 naming AS4991
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: 442 networks and 1,779 prefixes, as published 2026-10-24. 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