Site brush, but then to dialogue
Open IIS, select the IP ban the site, find the "ip address and domain restrictions" function, if not installed, open Server Manager, click Roles, Role Services to add the right window, find, find the "IP and domain restrictions" and select the Install . 
After opening the ip address and domain restrictions, right click the "Add refuse entry", set the pop-up window, where you can set a single IP rules rejection, can also set access prohibited IP segment. 
Finally, fill in the IP segment should pay attention to, the following examples illustrate:
IP address range: 115.239.212.0
mask or prefix: 255.255.255.0
deny IP segment are: 115.239.212 *
If you want to reject the IP segment is: 115.239 *. *, this will have to fill in:
IP address range: 115.239.0.0
mask or prefix: 255.255.0.0
If you want to reject the IP segment is: 115.239.16.1 - 115.239.16.127, this will have to fill in:
IP address range: 115.239.16.0
mask or prefix: 255.255.255.128
If you want to reject the IP segment is: 115.239.16.128 - 115.239.16.254, this will have to fill in:
IP address range: 115.239.16.128
mask or prefix: 255.255.255.128