Comment 10 for bug 1843932

netstat -tulpn
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp6 0 0 :::80 :::* LISTEN 1/python

I meant the following, but it doesn't listen for ipv4 also :
from flask import Flask

app = Flask(__name__)

@app.route("/")
def hello():
    html = "<h3>Hello Kitty {name}!</h3>"
    return html

if __name__ == "__main__":
    app.run(host='::', port=80)