SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/aplus-ipv6-size

How long is an IPv6 address?

128 bits, compared with 32 bits for IPv4.

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  1. 64 bits
  2. 128 bits ✔
  3. 256 bits

Why: IPv6 raised the address size from 32 bits to 128 bits. That gives far more addresses and room for better addressing structure.

Huh, didn't know that: RFC 8200 says IPv6 grew the address size to support more levels of addressing hierarchy.

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References

Answer: 128 bits. IPv6 raised the address size from 32 bits to 128 bits. That gives far more addresses and room for better addressing structure.

  1. RFC 8200 www.rfc-editor.org/rfc/rfc8200
    increases the IP address size from 32 bits to 128 bits, to support more levels of addressing hierarchy
    Checked 2026-10-10.

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