AS57728 CEZNET-AS CEZNET s.r.o.

CEZNET-AS CEZNET s.r.o. · registered in Czechia

IPv4 addresses15,3604 prefixes · <0.001% of announced IPv4

Rank in Czechia#43largest network in CZ by IPv4 space, of 570 · 0.19% of CZ

Rank worldwide#7,255of 79,396 networks with IPv4

IPv63 x /32 (196,608 x /48)3 prefixes

CountryCzechia599 ASNs registered there

Open AS57728 in ASN lookup Look up an IP in this network (81.25.16.1) All networks in Czechia

IPv4 prefixes

All 4 prefixes, in address order.

81.25.16.0/20
109.234.40.0/21
185.255.116.0/22
188.122.192.0/19

IPv6 prefixes

All 3 prefixes.

2a00:1800::/32
2a00:1807::/32
2a0a:b6c0::/32

Other ASNs named CEZNET-AS CEZNET s.r.o.

3 other networks use the same organisation name; together with AS57728 they announce 29,184 IPv4 addresses.

ASNNameIPv4 addresses

AS198002CEZNET-AS CEZNET s.r.o. CZ8,192

AS204064CEZNET-AS CEZNET s.r.o. CZ3,840

AS201654CEZNET-AS CEZNET s.r.o. CZ1,792

Similar-sized networks in Czechia

ASNNameIPv4 addresses

AS196735#40 AS-JONCZ PODA a.s.16,384

AS196822#41 SELECTSYSTEM-AS SELECT SYSTEM, s.r.o.16,384

AS197197#42 M-NET CETIN a.s.16,384

AS29321#44 CentroNetAS O2 Czech Republic, a.s.15,360

AS204666#45 TLAPNET-CZ Jiri Tlapak14,336

AS207187#46 TKRJASEK TKR Jasek, s.r.o.14,336

IP-to-ASN data: iptoasn.com (public domain). Snapshot downloaded 2026-11-11, refreshed daily. Ranges are what each network announces in BGP, not registry allocations. Data sources