Is it possible to use this notation in a firewall rule? I am having issues with homegroup telling me the computer joined to the home group is currently unavailable even though they are set not to hibernate/sleep. If I disable the firewall(s) then try I can connect to from one computer to another homegroup share. So I think there is an issue with the firewall rule(s). What I want to do is add a rule that says all computers in class C range 192.168.1.XXX /24 are allowed. I'm not sure how to accomplish this as I'm no networking guru. I understand the concept I think though.