IP version
IPv4 / IPv6 — 計算方法
IPv4 masks use 32 bits, while IPv6 network prefixes use 128 bits. CIDR /30 creates four IPv4 addresses, typically two usable hosts. /31 is useful for point-to-point links and allows both addresses; /32 identifies one address. IPv6 does not have IPv4 broadcast addresses.
よくある質問
Will this test my network?
No. It only calculates addresses and masks in your browser, without pinging or scanning anything.
What is the difference between network and broadcast?
For ordinary IPv4 subnets, the network and broadcast addresses are reserved; the intervening addresses are traditionally usable by hosts.
Why a separate result URL?
The result address contains the entered IP and prefix in query parameters, so it can be refreshed or copied. Avoid sharing sensitive internal IPs.
関連する計算機
重要な情報
Subnets and address blocks do not themselves configure a router. Check firewall rules, routes, VLAN settings and local policies before applying changes to operational networks. Special-use classifications are guidance and do not prove internet reachability.