How to enable port 5000 on AWS ubuntu [closed]

Question

I have a flask app running on AWS Ubuntu server on port 5000 (flask runs default on port 5000). But when I try to access the server on that port, it never connects.

I added a security group on AWS console as Custom TCP on port 5000 for any ip address 0.0.0.0/0, but still I cannot access it.

Do I have to restart the server? Or am I missing anything?

Let me know any additional information to provide.

Answer 1

In addition to allowing access to port 5000 via the Security Group, you also need to ensure that your app is listening on an IP which can accept TCP connections from outside. To listen on all IPs, in your app, use:

if __name__ == '__main__':
    app.run(host='0.0.0.0', debug = False)

Instead of:

if __name__ == '__main__':
    app.run(host='127.0.0.1', debug = False)

To see what address your application is listening on, you can run this command:

netstat -an | grep :5000

After making these changes, you will want to restart your Flask application.

I'm assuming you're just using this for development and testing, since you're keeping it on port 5000, but, when you're ready to deploy your application into production, you need to put it behind a real webserver. I would recommend using nginx with uWSGI. Here is a guide to configuring Flask + nginx + uWSGI, and here is the official documentation from Flask on the subject.

Answer 2

In addition to @Will's answer, its possible that whichever Ubuntu AMI you're using came with restrictive iptables rules by default. Use:

sudo iptables -L

to list any current rules that exist. Use:

sudo iptables -A INPUT -p tcp --dport 5000 -j ACCEPT

to open the port if necessary.