rand(0x100 - 2) + 2</p>

<p>Why not just use</p>

<c>
sub mac {
   return join ':',
      '00:96:14',
      sprintf('%02X', rand(0x30)),
      sprintf('%02X', rand(0x100)),
      sprintf('%02X', rand(0x100));
}

##</code><code>##

sub mac {
   return sprintf('00:96:14:%02X:%02X:%02X',
      rand(0x30),
      rand(0x100),
      rand(0x100),
   );
}