asn.dev

Autonomous system

AS57728 TELIN-AS

Unclassified RIPE

IPv4 addresses 15.36K 4 prefixes
IPv6 prefixes 3 counted as prefixes, not addresses
Countries 1 mostly CZ
Exchanges 0 recorded by PCH
Upstreams 1 0 downstream
Flagged prefixes 0 none

Summary

CEZNET

Czechia · AI-generated

business corporate czechia

TELIN-AS is operated by CEZNET s.r.o., the IT and telecommunications subsidiary of the Czech Energy Group (ČEZ).

What it's used for

  • The address space carries corporate and enterprise traffic, evidenced by netnames CZ-CEZNET21-20060227, CZ-CEZNET21-20100112, and CZ-CEZNET21-20180413, alongside CZ-MAGNALINK-20090604 for the Magnalink, a.s. segment.
  • With 15,360 IPv4 addresses announced across 4 prefixes and only 1 observed neighbour, the network functions as a self-contained internal corporate estate rather than a transit or access provider.
  • Traffic consists of internal corporate communications, data center connectivity, and enterprise services for the ČEZ group and its subsidiaries.

Notable

  • Registrants align with the announcer for three of the four prefixes, listing CEZNET hostmaster; CEZNET s.r.o., while the largest block 188.122.192.0/19 is registered to Magnalink, a.s., a related entity within the same corporate group.
  • The inventory is finely subdivided into four distinct IPv4 blocks and three IPv6 /32 prefixes, reflecting site-by-site segmentation typical of a large industrial corporation.

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

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

ASNetworkPaths seen
AS39791Telco Pro Services, a. s.394

Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-13, 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 4 prefixes · 15.36K addresses IPv6 3 prefixes

CountryNamePrefixes
CZCzechia7

Registry

Allocation record

RIPE · via Atlas (registry + RDAP)
Registry
RIPE
Handle
AS57728
Registry name
CEZNET-AS
Registrant
CEZNET-MNT
Abuse contact
dohled@ceznet.cz
Registered
2019-10-21
Last changed
2025-09-26
Allocation
allocated

Routing security

RPKI and IRR

Full detail
RPKI
100% valid · 8 valid, 0 with no ROA
ROAs
8 authorising AS57728
ASPA
no ASPA record
IRR
100% registered · 8 of 8 announcements
Route objects
8 naming AS57728

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: 436 networks and 1,771 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

Cross-check