Just a remark to always benchmark your code to make this statement. As newer releases of .Net Core also Regex gets faster and faster.
So better stay maintainable and readable and let the performance guys do their work
References:

• https://devblogs.microsoft.com/dotnet/regex-performance-improvements-in-net-5/
• https://devblogs.microsoft.com/dotnet/regular-expression-improvements-in-dotnet-7/
• https://devblogs.microsoft.com/dotnet/performance-improvements-in-net-8/#searchvalues which is/will be used by Regex under the hood

There is actually no difference as these functions are evaluated lazily.

Because none of the tests check for leading apostrophes

Short, but no bonus points for you i guess ^^

Haha I was joking that I didn't realize there was an IPAdress class we could use. This is the best solution hands down.

There were no restrictions in the conditions ¯\(ツ)/¯

Oh come on.....

Because it includes possible leading apostrophes how described in description.

I really like your Regex!

Beautiful

Elegant one, but I persannoly chose not to use regex because it is rather slow in general.

Good solutuion, but it will be better first to take elements and then select.