well, there's two ways i know of to go about this.

1) The regex from MRE :

^([01]?\d\d?|2[0-4]\d|25[0-5])\.([01]?\d\d?|2[0-4]\d|25[0-5])\.
([01]?\d\d?|2[0-4]\d|25[0-5])\.([01]?\d\d?|2[0-4]\d|25[0-5])
[download]

2) This is a pain in the ass to write out, so if i'm only going to be matching once, i'll sacrifice speed for readability:

sub validip {
  my ($ip)=@_;
  my $x;
  foreach ($ip=~/^(\d+)\.(\d+)\.(\d+)\.(\d+)$/){
    $x++ if(($_>=0)&&($_<=255));
  }
  return($x==4);
}
[download]

BlueLines

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