Sharepoint Network location

Hi, I being tried to enable the Network location by IP and I am getting this message - "Make sure the IP addresses and ranges are separated by commas, use CIDR notation, and don't overlap. Also make sure you allow your current IP address."

I planned to give a range of IP 172.16.1.5 to 254.

Anyone can specify how to enter the ip and how to enter cidr. Thanks in advance...