Subnets·IPv6 /32
IPv6
/32
2^96

IPv6 /32 prefix

/32 means the first 32 bits are the network and 96 are left for hosts. That is 2^96 addresses.

Addresses are 128 bits, so nobody writes a mask — only the prefix length. A home gets a /56, a single network a /64.

Prefix
/32
Host bits
96
Addresses
2^96
Usable hosts
2^96
/64 networks inside
2^96
Nibble boundary
Yes

Blocks reserved at this length

Blocks the standards set aside. The addresses themselves are the same everywhere, so they are left as they are.

2001:db8::/322001::/32

Prefixes either side

How to read this

  • /24 means the first 24 bits are the network; the remaining 8 hold the addresses inside it.
  • Each extra bit splits the network in two and halves the addresses.
  • Usable addresses are normally the total minus two — the network and broadcast addresses.
  • IPv6 has no broadcast, so nothing is subtracted. One network is conventionally a /64.

Frequently asked questions

Q. How many addresses are in a /32?

2^96, of which 2^96 can actually be handed out.

Q. How is a /32 written?

IPv6 uses no mask — you simply write /32.

Q. How many /64 networks fit in a /32?

2^96.

Q. How many host bits are there?

96. Each extra network bit halves the addresses.