Many times I find myself wanting to spin up a simple test service for a firewall rule. You can bring up a simple web server in Python3 from the command line.
python3 -m http.serverThis will start it on port 8000 (http://0.0.0.0:8000). To start it on port 80 you will need root privileges, as per any port from 0-1023.
sudo python3 -m http.server 80