AS43542 OptoNet-AS OptoNet Communication, spol. s.r.o.

OptoNet-AS OptoNet Communication, spol. s.r.o. · registered in Czechia

IPv4 addresses7,9365 prefixes · <0.001% of announced IPv4

Rank in Czechia#80largest network in CZ by IPv4 space, of 570 · 0.10% of CZ

Rank worldwide#10,955of 79,396 networks with IPv4

IPv61 x /32 (65,536 x /48)1 prefixes

CountryCzechia599 ASNs registered there

Open AS43542 in ASN lookup Look up an IP in this network (78.156.128.1) All networks in Czechia

IPv4 prefixes

All 5 prefixes, in address order.

78.156.128.0/21
78.156.136.0/22
78.156.141.0/24
78.156.142.0/23
78.156.144.0/20

IPv6 prefixes

All 1 prefix.

2a00:d940::/32

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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