Impossible to Open TCP Port to External App

Hey Mike! 👋

I saw your earlier message and updated my response there too, but I wanted to follow up here to clear things up.

First off, I can assure you this isn’t a money thing, DigitalOcean doesn’t charge extra to open TCP ports on Droplets.

Droplets give you full control over your server, and opening ports is definitely possible. It just comes down to a couple of key configurations that I mentioned in my previous reply:

1. Make sure your application is actually running and listening on the port you want to open. Also, ensure it’s bound to 0.0.0.0 (not localhost) to accept external connections. Example for a Node.js app:

   app.listen(8080, '0.0.0.0');
   

2. If you’re using DigitalOcean Cloud Firewalls, confirm that the port is allowed for inbound traffic. If you’re using a firewall on the Droplet like ufw, you can open the port like this:

   sudo ufw allow 8080/tcp
   sudo ufw reload
   

   No firewall? Then once your service is running, it should be accessible.

3. Run this command to check if the port is being listened on:

   sudo netstat -plant | grep 8080
   

   If it shows up, the service is listening. You can then test the port externally with:

   curl http://your_droplet_ip:8080
   

On another note, in rare cases, your local network or ISP might block certain ports. Testing from a different network or using a VPN could rule this out.

Droplets give you complete freedom over networking, so there are no hidden restrictions here.

Let me know how it goes! If it is still not working, feel free to share the output of the netstat command here.

- Bobby

Heya,

Are you sure anything is listening on that port? Opening port but nothing listening on that port will make it appear as closed from the outside.

Basically, you need to have something listen to that port in order to open it to the outside world.