Autonomous system
AS30031 MIMECAST-US - Mimecast North America Inc
Unclassified ARIN
Summary
Mimecast
security email business cloud
The AS handle MIMECAST- is held by Mimecast North America Inc.
What it's used for
- The address space carries email security infrastructure, evidenced by reverse DNS entries such as
us-smtp-delivery-126.mimecast.comandusb-smtp-delivery-126.mimecast.com. - The AS announces 5632 IPv4 addresses across 13 prefixes and 3 IPv6 prefixes, while maintaining only 4 observed neighbours, a ratio that indicates a dedicated business network rather than a transit provider.
Notable
- Registrants are consistent with the announcer, including Mimecast North America Inc, Mimecast Services Limited, and Mimecast South Africa, alongside legacy CenturyLink Communications, LLC blocks.
- The address inventory is finely subdivided into /23 and /24 blocks, reflecting an internal corporate estate segmented by site or function rather than a broad access network.
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 2026-10-31, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.
Address space
Summary
IPv4 13 prefixes · 5.63K addresses IPv6 3 prefixes
| Country | Name | Prefixes |
|---|---|---|
| US | United States of America | 16 |
Registry
Allocation record
- Registry
- ARIN
- Handle
AS30031- Registry name
- MIMECAST-US
- Registrant
- Mimecast North America Inc
- Abuse contact
- abuse@mimecast.com
- Registered
- 2017-07-07
- Last changed
- 2017-07-07
- Allocation
- assigned
Routing security
RPKI and IRR
- RPKI
- 77% valid · 20 valid, 6 with no ROA
- ROAs
- 25 authorising AS30031
- ASPA
- no ASPA record
- IRR
- 96% registered · 25 of 26 announcements
- Route objects
- 46 naming AS30031
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: 447 networks and 1,843 prefixes, as published 2026-11-01. 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