IPv4 枯竭

Name: IPv4 Address Exhaustion Tracker
Creator: WorldIP.io
License: https://creativecommons.org/licenses/by/4.0/

32 位 IPv4 地址空间有 4,294,967,296 个地址的硬性上限。IANA 于 2011 年 2 月 3 日分配了其最后一个未保留的 /8。

95.41%

IPv4 空间已分配

Allocated

4,097.98M

4,097,983,851

Unallocated / reserved

196.98M

196,983,445

Total IPv4

4,294.97M

2³²

By Regional Internet Registry

RIR	IPs managed	Share of allocated	Prefixes
ARIN	2,071.92M	51.2%	350,842
APNIC	924.56M	22.8%	61,629
RIPE	776.11M	19.2%	209,902
LACNIC	183.97M	4.5%	21,779
AFRINIC	89.75M	2.2%	18,320

1981 — IPv4 defined in RFC 791.
1993 — Classful addressing replaced with CIDR (RFC 1519) to slow exhaustion.
Feb 2011 — IANA allocates the last /8 to APNIC. Top-level free pool exhausted.
Apr 2011 — APNIC enters "last /8" policy (1 /22 per LIR).
Sep 2012 — RIPE NCC enters last /8 policy.
Jun 2014 — LACNIC free pool exhausted.
Sep 2015 — ARIN free pool exhausted.
Nov 2019 — RIPE NCC runs out (single /22 allocations only from waitlist).
Ongoing — All new allocations come from returns, transfers, or waitlists. Secondary market prices ~$25–50/IP.