AS5610 — O2-CZECH-REPUBLIC O2 Czech Republic, a.s.

AS5610 announces 47 IPv4 prefixes covering 1,540,608 addresses and 4 IPv6 prefixes.

About this network

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.

Announced prefixes

• 5.23.39.0/24
• 37.188.128.0/17
• 80.188.0.0/16
• 81.90.160.0/20
• 83.69.32.0/19
• 83.208.0.0/16
• 85.70.0.0/15
• 85.160.0.0/15
• 85.193.0.0/18
• 88.83.160.0/19
• 88.100.0.0/14
• 90.176.32.0/19
• 90.176.64.0/18
• 90.176.128.0/17
• 90.177.0.0/16
• 90.178.0.0/15
• 90.180.0.0/14
• 91.191.64.0/22
• 91.191.68.0/24
• 91.191.70.0/23
• 91.191.72.0/21
• 91.191.84.0/22
• 91.191.88.0/21
• 91.191.96.0/19
• 91.193.132.0/22
• 91.213.10.0/24
• 91.232.82.0/24
• 92.243.192.0/19
• 109.80.0.0/15
• 160.218.0.0/16
• 161.195.144.0/24
• 185.61.228.0/22
• 185.143.112.0/22
• 193.17.13.0/24
• 193.84.12.0/22
• 194.50.248.0/23
• 194.165.47.0/24
• 194.228.0.0/17
• 194.228.128.0/20
• 194.228.144.0/21
• 194.228.152.0/22
• 194.228.158.0/23
• 194.228.160.0/19
• 194.228.192.0/18
• 195.5.186.0/24
• 217.117.208.0/20
• 217.194.160.0/20
• 2001:67c:dd4::/48
• 2001:41d8::/32
• 2a00:1028::/29
• 2a02:9b8::/31

Upstream networks

• AS1299 Arelion Sweden AB
• AS174 Cogent Communications, LLC
• AS6939 Hurricane Electric LLC
• AS29504 Freenet Liberec, z.s.
• AS24482 SG.GS
• AS1764 Next Layer Telekommunikationsdienstleistungs- und Beratungs GmbH
• AS47232 ISP Alliance a.s.
• AS6461 Zayo Bandwidth
• AS202297 Skylon Solutions Limited
• AS8218 Zayo Infrastructure France SA
• AS33891 Core-Backbone GmbH

Downstream networks

• AS42908 O2 Czech Republic, a.s.
• AS16246 O2 Czech Republic, a.s.
• AS206613 Tipsport.net a.s.
• AS211274 Quadruple a.s.
• AS35096 Alef Nula a.s.
• AS197353 NN Management Services, s.r.o.
• AS203411 FORTUNA GAME a.s.
• AS215711 The Ministry of Agriculture of the Czech Republic
• AS38952 MAFRA, a.s.
• AS204372 PPF banka a.s.
• AS205400 VIVO CONNECTION spol. s r.o.
• AS49580 Monet +, a.s.
• AS205233 KBC GLOBAL SERVICES NV
• AS208712 CENDIS, s.p.
• AS198282 CAH Building s.r.o.
• AS208906 SYNOT ICT Services, a.s.
• AS50948 AMDOCS (UK) LIMITED
• AS197920 SKODA ICT s.r.o.
• AS28952 O2 Business Services, a.s
• AS43866 Altron a.s.
• AS198605 AVAST Software s.r.o.
• AS198991 TV Nova sro
• AS21241 Global Payments Europe, s.r.o.
• AS199059 Maurice Ward & Co., s.r.o.
• AS47941 Red Hat Ltd

Adjacent networks

• AS1299 Arelion Sweden AB
• AS16246 O2 Czech Republic, a.s.
• AS174 Cogent Communications, LLC
• AS6939 Hurricane Electric LLC
• AS42908 O2 Czech Republic, a.s.
• AS29504 Freenet Liberec, z.s.
• AS24482 SG.GS
• AS202297 Skylon Solutions Limited
• AS206613 Tipsport.net a.s.
• AS211274 Quadruple a.s.
• AS35096 Alef Nula a.s.
• AS197353 NN Management Services, s.r.o.
• AS203411 FORTUNA GAME a.s.
• AS215711 The Ministry of Agriculture of the Czech Republic
• AS1764 Next Layer Telekommunikationsdienstleistungs- und Beratungs GmbH
• AS28952 O2 Business Services, a.s
• AS38952 MAFRA, a.s.
• AS204372 PPF banka a.s.
• AS205400 VIVO CONNECTION spol. s r.o.
• AS49580 Monet +, a.s.
• AS205233 KBC GLOBAL SERVICES NV
• AS208712 CENDIS, s.p.
• AS198282 CAH Building s.r.o.
• AS208906 SYNOT ICT Services, a.s.
• AS50948 AMDOCS (UK) LIMITED

Routing security

• RPKI: 69 valid, 0 invalid and 3 not-found announcements; 129 ROAs.
• ASPA: none published.
• IRR: 97% of announcements registered; 191 route objects.
• Listed in as-sets: AS-CTIOL, AS-O2CZSEC, AS-SEABONE-V6, AS-SEABONECUSTEU, AS12570:AS-NIX-PEERS, AS24971:AS-MAI-NIX-PEER, AS42000:AS-NIXCZ-PEERINGS, AS5578:AS-SIXPEERS, AS8251:AS-NIX-PEERINGS.

Internet exchanges

• NIX.CZ - Neutral Internet eXchange for the Czech Republic — Prague, Czech Republic