Regex to check valid MAC address
regex = ( " ^ ( [0-9A - Fa - f ] {2 } [ : - ] ) " + " { 5 } ( [0-9A - Fa - f ] {2 } ) | " + " ( [0-9a - fA - F ] {4 } \\ . " + " [ 0-9a - fA - F ] {4 } \\ . " + " [ 0-9a - fA - F ] {4 } ) $ " ) NEW_LINE