CIDR calculator

CIDR calculatorの使い方

何を計算するか、いつ使うか

Works out the 範囲、subnet mask, wildcard mask、a CIDR block size個でIPv4またはIPv6、accepts an address with a dotted mask,、converts a startとCIDR blocks that cover them exactly. end address into the smallest list

使い方の手順

1. Choose “CIDR block”または“Address 範囲”.
2. Enter a block such as 192.168.10.0/22、or the first、a range. last address
3. Read the firstとlast address、masks、hosts. number
4. CIDR 個のブロック. For a 範囲, コピー the list

各入力項目の意味

• CIDR block,またはaddress with mask – An IPv4またはIPv6 address followed by /prefix、or an IPv4 address、a dotted mask such as 255.255.252.0.
• Firstとlast address – a range, both IPv4またはboth IPv6. The two ends

結果の読み方

• Address 範囲 – The firstとthe block, last addressとaddresses. the number
• Masks – サブネットマスクとwildcard mask個でIPv4.
• Usable hosts – Addresses available個でdevices: the total minus the networkとbroadcast addresses、except /31、/32.
• CIDR 個のブロック – 個のブロック that covers it. For a 範囲, the 最小値 set

計算式

A /n block has 2^(ビット − n) addresses、where bitsは32です個でIPv4、128個でIPv6. The network addressはthe given address with the host bits set to zero. For IPv4 the usable hosts are 2^(32 − n) − 2. IPv6 uses BigInt arithmeticです個でexact results.

計算例

192.168.10.0/22 covers 192.168.8.0〜192.168.11.255、whichは1,024 addressesです、1,022 usable hosts, with mask 255.255.252.0.

前提と限界

• removing the network Usable hosts follow the usual conventionとbroadcast addresses. /31 links use both addressesと/32はa single host.です
• IPv6 個のブロック have いいえ broadcast address.
• A 範囲 that does not 引き締まっている one block returns several 個のブロック.

よくある間違い

• Entering a host addressとexpecting it〜be the network address. The tool shows the real network address.
• Using a non-contiguous mask such as 255.0.255.0, whichはnot valid.です
• Mixing an IPv4 first address with an IPv6 last address.

よくある質問

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