Where does this come from, and can I check it?

The last five free blocks were handed to regional registries that February, forcing a move to 128-bit addressing. The figure is taken from IETF, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a technology fact?

Yes. It sits on the Technology shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

What else can I read about it?

The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

The world ran out of IPv4 addresses in 2011

The last five free blocks were handed to regional registries that February, forcing a move to 128-bit addressing IPv4 uses 32-bit addresses, giving about 4.3 billion possible values, a number that seemed ample when the protocol was written. The central registry allocated its final five blocks on 3 February 2011, and networks have since traded, shared and rationed what remains. IPv6 uses 128 bits, but adoption is gradual because every device along a path has to understand it. It sits in Mondo's technology collection, one of 200 facts that each trace back to the reference below.

Where this comes from

IETF

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

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Tags: ipv4, ipv6, internet

The world ran out of IPv4 addresses in 2011: the short answers

Where does this come from, and can I check it?: The last five free blocks were handed to regional registries that February, forcing a move to 128-bit addressing. The figure is taken from IETF, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a technology fact?: Yes. It sits on the Technology shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.