asn.dev

Autonomous system

AS203376 MAILKIT

Unclassified RIPE

IPv4 addresses 1.02K 1 prefixes
IPv6 prefixes 1 counted as prefixes, not addresses
Countries 1 mostly CZ
Exchanges 0 recorded by PCH
Upstreams 2 0 downstream
Flagged prefixes 0 none

Summary

Mailkit

Czechia · AI-generated

business czech mail small

The AS handle MAILKIT is held by Mailkit s.r.o.

What it's used for

  • The space carries corporate infrastructure for a Czech email service provider, as indicated by the netname CZ-MAILKIT-20160202 and registrants including Mailkit NOC and Mailkit FBL.
  • The network announces 1024 IPv4 addresses and 1 IPv6 prefix, with only 2 observed neighbours, indicating a small, self-contained business network rather than a transit or large access provider.
  • Traffic from this AS consists of web and API endpoints for Mailkit's email hosting services, supporting customer access to mailboxes and related administrative functions.

Notable

  • Registrants align with the announcer, listing Mailkit NOC, Mailkit FBL, Mailkit s.r.o., and Abuse-C Role.
  • The address inventory consists of a single IPv4 block (185.136.200.0/22) and one IPv6 prefix (2a06:ffc0::/29), reflecting a compact, unified 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

2 upstream, 0 downstream and 4 adjacent networks observed; most-used upstreams first.

ASNetworkPaths seen
AS15685CASABLANCA INT a.s.160
AS21430WIA spol. s.r.o.135

Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-26, 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 1 prefixes · 1.02K addresses IPv6 1 prefixes

CountryNamePrefixes
CZCzechia2

Registry

Allocation record

RIPE · via Atlas (registry + RDAP)
Registry
RIPE
Handle
AS203376
Registry name
MAILKIT
Registrant
cz-mailkit-1-mnt
Abuse contact
abuse@mailkit.com
Registered
2016-02-02
Last changed
2018-09-04
Allocation
allocated

Routing security

RPKI and IRR

Full detail
RPKI
100% valid · 6 valid, 0 with no ROA
ROAs
9 authorising AS203376
ASPA
no ASPA record
IRR
100% registered · 6 of 6 announcements
Route objects
2 naming AS203376

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: 446 networks and 1,852 prefixes, as published 2026-10-27. 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