Getting number of IPv6 addresses from Ipv6 CIDR in PHP

Question

Is there a way to get the number of IPv6 addresses from a Ipv6 CIDR?

for example: CIDR: 2403:3E00::/32 => need get number of ipv6 addresses: 79228162514264337593543950336

Is it possible to add in the function on that page (PHP5 calculate IPv6 range from cidr prefix) - http://stackoverflow.com/questions/10085266/php5-calculate-ipv6-range-from-cidr-prefix/10086404#10086404 that it additional return number of ip addresses in CIDR Prefix: ... First: ... Last: .. and NumberIP: ... ? — user2253402, Aug 18 '13 at 20:28

score 0 · Answer 1 · answered Aug 18 '13 at 18:04

0

An IPv6 address has 128 bits, of which (slightly simplified) a number are dedicated to network address, and the rest are dedicated to host addresses.

In your case, 32 bits are dedicated to the network part (/32), so the other 96 are dedicated to host addresses.

2^(128-32) = 2^96 = 79228162514264337593543950336 hosts

answered Aug 18 '13 at 18:04

Joachim Isaksson

To maintain precision you can use bcpow for this `echo bcpow(2, 128-32), "\n";` – Orangepill Aug 18 '13 at 18:12

user4271704 · Answer 2 · 2015-07-15T19:22:05.887

0

2^(128-32) = 2^96 = 79228162514264337593543950336

is wrong, you still need to

79228162514264337593543950336 - 1 = 79228162514264337593543950335 hosts

PS. sorry I could not comment it to the answer of Joachim because of reputation, this is why I am not much interested in stackoverflow.

edited Jul 15 '15 at 19:22

answered Jul 15 '15 at 19:15

user4271704

2 Answers2