Autonomous system
AS21874 MMC
Unclassified ARIN
Summary
Marsh & McLennan Companies
business insurance corporate internal
MMC is the autonomous system for Marsh & McLennan Companies, a global professional services firm.
What it's used for
- The address space is registered to Marsh Inc., a subsidiary of Marsh & McLennan, with netnames
MMC-205-156indicating internal corporate usage. - The AS announces 2304 IPv4 addresses across 2 prefixes and maintains 2 observed neighbours, a ratio consistent with an internal corporate estate rather than a transit or access network.
Notable
- Registrants for both announced prefixes are Marsh Inc., aligning with the announcer identity of MMC.
- Marsh & McLennan Companies is the holding company for Marsh Inc., which provides risk and insurance services.
- The inventory consists of two contiguous IPv4 blocks: 205.156.184.0/21 and 205.156.183.0/24.
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 2026-10-14, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.
Address space
Summary
IPv4 2 prefixes · 2.30K addresses IPv6 0 prefixes
| Country | Name | Prefixes |
|---|---|---|
| US | United States of America | 2 |
Registry
Allocation record
- Registry
- ARIN
- Handle
AS21874- Registry name
- MMC
- Registrant
- MMC
- Abuse contact
- abuse@mmc.com
- Registered
- 2001-07-03
- Last changed
- 2022-12-02
- Allocation
- assigned
Routing security
RPKI and IRR
- RPKI
- 100% valid · 2 valid, 0 with no ROA
- ROAs
- 8 authorising AS21874
- ASPA
- no ASPA record
- IRR
- 100% registered · 2 of 2 announcements
- Route objects
- 13 naming AS21874
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 1,773 prefixes, as published 2026-10-13. 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