Here's a different approach specifically for the 4-element dotted form:

  (eval$_)=~/^[\0-\xff]{4}\z/

[download]

This requires perl-5.6.0 or later; extending it for the other forms becomes rather uglier:

  (eval"0.0.$_")=~/^\0\0(.|[\0-\xff]([\0-\x{ffffff}]|[\0-\xff]([\0-\x{
+ffff}]|[\0-\xff]{2})))\z/s

[download]

Of course the usual caveats about eval apply, but this is golf ...

Hugo

In reply to Re: (Golf) Expression for matching numeric IP addresses by hv
in thread (Golf) Expression for matching numeric IP addresses by trantor

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