Autonomous system
AS3620 MCIASN-BLK
Unclassified ARIN
Summary
Verizon Business (legacy MCI)
enterprise legacy
One of the legacy MCI autonomous system numbers (MCIASN-BLK) now held by Verizon Business.
What it's used for
- Announcing a single small block of Verizon Business address space; the ASN originates one
/24rather than acting as a general-purpose backbone. - Retained from MCI's network as part of the address and ASN estate Verizon inherited.
Notable
MCIASN-BLKwas a block of AS numbers rather than a single assignment — MCI held a contiguous run of them, and several sit adjacent to this one in the low-3600s. The handle names the block, not the specific network behind it.- Carrier-held space. Public registry data does not identify a distinct end-network here, so the honest description is simply "Verizon Business".
Interesting
- The handle is a fossil: MCI was absorbed by Verizon in 2006, but the ARIN record still carries the MCI name. Handles routinely outlive the companies that earned them.
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 |
|---|---|---|
| AS703 | Verizon Business | 58 |
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 1 prefixes · 256 addresses IPv6 0 prefixes
| Country | Name | Prefixes |
|---|---|---|
| US | United States of America | 1 |
Registry
Allocation record
- Registry
- ARIN
- Handle
AS3617- Registry name
- MCIASN-BLK
- Registrant
- Verizon Business
- Abuse contact
- abuse@verizon.com
- Registered
- 1994-05-24
- Last changed
- 2024-07-02
- Allocation
- assigned
Routing security
RPKI and IRR
- RPKI
- 0% valid · 0 valid, 1 with no ROA
- ROAs
- 0 authorising AS3620
- ASPA
- no ASPA record
- IRR
- 100% registered · 1 of 1 announcements
- Route objects
- 1 naming AS3620
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 1,771 prefixes, as published 2026-10-15. 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