The Shortest IPv6 Addresses / 最短的 IPv6 地址

I was looking for the shortest possible IPv6 equivalent of 1.1.1.1 (and its secondary 1.0.0.1, sometimes abbreviate 1.1).

我一直在寻找 1.1.1.1（及其备用地址 1.0.0.1，有时简写为 1.1）的最短 IPv6 等效地址。

Method / 方法

An IPv6 address is 128 bits long, written as 8 hexadecimal groups of 16bits. The :: shorthand replaces a run of zeros. The shortest addresses are therefore those where only the first group is non-zero: X::.

IPv6 地址长度为 128 位，写作 8 组 16 位的十六进制数。:: 缩写用于代替连续的零。因此，最短的地址就是那些只有第一组非零的地址：X::。

Only the global unicast block 2000::/3 is actually usable. Every other block is reserved, unroutable, or too long to write out. Since we’re looking at the first 16-bit block, that leaves us with 13 variable bits. Not a lot, I can just scan through those!

只有全球单播地址块 2000::/3 是实际可用的。其他所有地址块要么被保留，要么不可路由，要么书写长度过长。由于我们关注的是第一个 16 位块，这留下了 13 个可变位。数量不多，我可以直接扫描一遍！

The script / 脚本

For any script with fewer than 3 control structures, I tend to default to my shell of choice, fish.

对于任何控制结构少于 3 个的脚本，我倾向于默认使用我最喜欢的 shell：fish。

for i in (seq 0 8192)
  set ip_num (math 8192 + $i)
  set current_ip (printf '%x::' $ip_num)
  if ping -6 $current_ip -c 1 -W 0.7 &>/dev/null
    echo $current_ip
  end
end | tee result_ipv6

The results / 结果

Only 4 IPs responded to my pings.

只有 4 个 IP 地址响应了我的 ping 请求。

Address	RIR	Who	DNS?	Avg. response time
2409::	APNIC	Indian state government via the NKN	✅ yes	436ms
2600::	ARIN	Cogent (US-based ISP)	❌ no	173ms
2a09::	RIPE	Tom — for dns.sb	✅ yes	163ms
2a11::	RIPE	Tom — for dns.sb	✅ yes	161ms

After re-running the script from a non-residential IP, I got 3 additional results:

在从非住宅 IP 重新运行脚本后，我又得到了 3 个结果：

Address	RIR	Who
2002::	IANA	I have no idea why I’m getting a response. It’s the 6to4 address corresponding to 0.0.0.0
2a12::	RIPE	The info is a bit vague, but it’s apparently Van Veen Beheer B.V.
2c0f::	AFRINIC	Satsoft CC, a South African telecommunications company

地址	RIR	归属
2002::	IANA	我不知道为什么会收到响应。这是对应于 0.0.0.0 的 6to4 地址。
2a12::	RIPE	信息有点模糊，但显然是 Van Veen Beheer B.V. 公司。
2c0f::	AFRINIC	Satsoft CC，一家南非电信公司。

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