I have a hotspot here at home and i wanted to block out some domains such that if they are detected, a message is sent to the respective user notifying them that the domain is blocked. Do you know of any software or setting that i can use to achieve this goal
For blocking some of the domains from your internet can be done with the use of firewall.
Firewall is the software or hardware devices which filters the traffic. The traffic which flows from your network through a internet connection.
What firewall can do:
1.  Firewall can block certain IP addresses.
2.  You can allow access to certain specific domain names or domain names extension like .edu or .org with the use of firewall
3.  It also blocks the ports. You can allow some of the required ports through firewall. This will help to maintain the kind of data flow you want.
It will help you to block the domains which you do not want to access.
