What is the smallest regular expression for IP?

Question

Regular Expressions

Daviche decided to see what the Internet says about this.
And to be honest, I was very disappointed, then real kilometer crutches do not pass all the validation.
In general, without thinking twice, I threw my own.
Is there any other way to reduce the size of the expression?
https://regex101.com/r/59OOQY/1
Condition:
Ipv4
exact match
inability to enter ip above 255
inability to enter any expression other than ip.
Exclude any left characters.
Minimum size.

Answer 1

If we assume that the IP address must necessarily be from 4 numbers from 0 to 255, separated by three dots, then perhaps this:
^(1?\d{1,2}|2[0-4]\d|25[0-5])(\.(?1)){3}$