title: Invalid MAC Address with correct format
body: <p>I am making a program that generates random MAC addresses and I am having validation issues.  For instance the following MAC address shows up as invalid:</p>
  
  <pre><code>E7:BA:1E:34:9B:B0
  </code></pre>
  
  <p>Each group here is between the 0-255 hex value range though, whats the deal?  Am I missing some other formatting constraint?</p>