Autonomous system
AS43757 ICZAS-CZ ICZ a.s.
Unclassified APNIC
Summary
ICZ a.s.
business czech icz
The AS handle ICZAS- is held by ICZ a.s.
What it's used for
- The address space carries corporate infrastructure, evidenced by the netnames
ICZ-CZandICZ-SKand the reverse DNS recordfort.i.cz. - The network announces 2304 IPv4 addresses across 2 prefixes and 1 IPv6 prefix, with 3 observed neighbours, indicating a small-scale business or internal corporate estate rather than a large access or transit provider.
- Traffic from this AS consists of internal corporate endpoints and services for ICZ a.s., a Czech company.
Notable
- Registrants for both announced prefixes are listed as
ICZ Hostmaster; ICZ a.s.; Abuse-C Role, which aligns with the AS holder. - The inventory includes prefixes in both Czechia and Slovakia (indicated by the
ICZ-SKnetname), suggesting a cross-border corporate presence. - The address inventory is compact, consisting of a /21 and a /24 in IPv4 and a single /48 in IPv6.
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 2026-11-03, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.
Address space
Summary
IPv4 2 prefixes · 2.30K addresses IPv6 1 prefixes
| Country | Name | Prefixes |
|---|---|---|
| CZ | Czechia | 3 |
Registry
Allocation record
- Registry
- APNIC
- Handle
AS43757- Registry name
- ICZAS-CZ
- Registrant
- ICZAS-MNT
- Abuse contact
- abuse@i.cz
- Registered
- 2007-09-24
- Last changed
- 2025-10-02
- Allocation
- allocated
Routing security
RPKI and IRR
- RPKI
- 100% valid · 3 valid, 0 with no ROA
- ROAs
- 3 authorising AS43757
- ASPA
- no ASPA record
- IRR
- 100% registered · 3 of 3 announcements
- Route objects
- 3 naming AS43757
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: 451 networks and 1,853 prefixes, as published 2026-11-04. 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