The shortest IPv6 addresses

2026-09-06T00:57:26.000

The Shortest IPv6 Addresses

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).

Method

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::.

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!

The script

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

Only 4 IPs responded to my pings.

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