asn.dev

Autonomous system

AS39588 MIMECAST-DE Mimecast Services Limited

Unclassified RIPE

IPv4 addresses 2.82K 6 prefixes
IPv6 prefixes 1 counted as prefixes, not addresses
Countries 1 mostly GB
Exchanges 0 recorded by PCH
Upstreams 3 0 downstream
Flagged prefixes 0 none

Summary

Mimecast

United Kingdom · AI-generated

security email business

MIMECAST-DE is operated by Mimecast Services Limited.

What it's used for

  • The address space carries email security infrastructure, evidenced by reverse DNS entries such as de-smtp-delivery-128.mimecast.com and netnames like DE-MIMECAST-20180801 and EU-MIME-01.
  • The AS announces 2816 IPv4 addresses across 6 prefixes and 1 IPv6 prefix, with only 3 observed routing neighbours, indicating a small, dedicated corporate network rather than a transit or access provider.
  • Traffic from this AS consists of Mimecast's email security and risk management services, including SMTP delivery endpoints for its global customer base.

Notable

  • Registrants align with the announcer, including Mimecast - CoreGrid, Mimecast Germany GmbH, and Mimecast North America Inc, with one prefix (51.163.158.0/23) registered to Equinix EMEA Admin.
  • The address inventory is finely subdivided across multiple registrants and netnames, reflecting site-by-site segmentation for a global 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

Full topology · Graph

Internet exchanges

No exchange port on file. Many exchanges publish no participant list, so this is not proof of absence.

Transit providers

3 upstream, 0 downstream and 6 adjacent networks observed; most-used upstreams first.

ASNetworkPaths seen
AS6461Zayo Bandwidth275
AS3356Level 3 Parent, LLC195
AS24989Equinix (Germany) GmbH163

Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-11-01, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.

Address space

Summary

Shape and geography

IPv4 6 prefixes · 2.82K addresses IPv6 1 prefixes

CountryNamePrefixes
GBUnited Kingdom7

Registry

Allocation record

RIPE · via Atlas (registry + RDAP)
Registry
RIPE
Handle
AS39588
Registry name
MIMECAST-DE
Registrant
MCSL-RIPE-MNT
Abuse contact
abuse@mimecast.com
Registered
2017-11-07
Last changed
2019-03-28
Allocation
allocated

Routing security

RPKI and IRR

Full detail
RPKI
79% valid · 11 valid, 3 with no ROA
ROAs
13 authorising AS39588
ASPA
no ASPA record
IRR
100% registered · 14 of 14 announcements
Route objects
31 naming AS39588

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 2026-11-02. 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

Cross-check