Autonomous system
AS5610 O2-CZECH-REPUBLIC
Unclassified RIPE
Summary
O2 Czech Republic
isp legacy
O2-CZECH-REPUBLIC is the main autonomous system of O2 Czech Republic, a.s., the country's largest telecommunications operator, headquartered at Za Brumlovkou in Prague. It is the successor to the Czech incumbent and one of the largest networks registered in the RIPE region by address count.
What it's used for
Consumer and business internet access across the Czech Republic — fixed broadband, mobile data and corporate connectivity — plus transit for a long tail of downstream Czech networks. Around 1.5 million IPv4 addresses, overwhelmingly subscriber space.
Notable
Eyeball network. Addresses here are end users, so expect residential access patterns, NAT and dynamic assignment rather than servers. The RIPE object still lists Telia and Cogent as upstreams and a large peering fabric at NIX.CZ.
Interesting
The aut-num remarks read like an accidental customer list: dozens of named Czech downstreams and peers — banks, media groups, government registries, small regional ISPs — left in the object over the years. It is one of the more candid records in the RIPE database, and a reminder that whois objects often preserve operational history nobody meant to publish.
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
Recorded at 1 exchange in 1 country, largest first.
| Exchange | Location | Their address |
|---|---|---|
| NIX.CZ - Neutral Internet eXchange for the Czech Republic | Prague, Czech Republic | 91.210.16.160 |
Transit providers
10 upstream, 43 downstream and 79 adjacent networks observed; most-used upstreams first.
Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-11, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.
Address space
Summary
IPv4 101 prefixes · 1.54M addresses IPv6 4 prefixes
| Country | Name | Prefixes |
|---|---|---|
| CZ | Czechia | 105 |
Registry
Allocation record
- Registry
- RIPE
- Handle
AS5610- Registry name
- O2-CZECH-REPUBLIC
- Registrant
- AS5610-MTN
- Abuse contact
- abuse@o2.cz
- Registered
- 2002-07-22
- Last changed
- 2024-06-12
- Allocation
- allocated
Routing security
RPKI and IRR
- RPKI
- 94% valid · 68 valid, 4 with no ROA
- ROAs
- 128 authorising AS5610
- ASPA
- no ASPA record
- IRR
- 99% registered · 71 of 72 announcements
- Route objects
- 189 naming AS5610
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: 432 networks and 1,768 prefixes, as published 2026-10-12. 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