Hosting a Flask app

The Flask quickstart guide is great. However when it was time to deploy it on my DigitalOcean, I found it impossible to access.

The doc says you should run to open it to external machines:

flask run --host=

Yet I couldn't reach it remotely. Turns out my server was blocking port 5000. To open it I had to run:

ufw allow 5000/tcp

It turns out this is highly discouraged, and I should host it in a safer way. lists the alternatives. I'll read up on them later.