51.12.24.0-51.12.31.255 51.12.24.0/21
51.12.32.0-51.12.63.255 51.12.32.0/19
51.12.64.0-51.12.95.255 51.12.64.0/19
51.12.96.0-51.12.103.255 51.12.96.0/21