Can't get docker to accept request over the internet

Question

So, I'm trying to get Jenkins working inside of docker as an exercise to get experience using docker. I have a small linux server, running Ubuntu 14.04 in my house (computer I wasn't using for anything else), and have no issues getting the container to start up, and connect to Jenkins over my local network.

My issue comes in when I try to connect to it from outside of my local network. I have port 8080 forwarded to the serve with the container, and if I run a port checker it says the port is open. However, when I actually try and go to my-ip:8080, I will either get nothing if I started the container just with -p 8080:8080 or "Error: Invalid request or server failed. HTTP_Proxy" if I run it with -p 0.0.0.0:8080:8080.

I wanted to make sure it wasn't jenkins, so I tried getting just a simple hello world flask application to work, and had the exact same issue. Any recommendations? Do I need to add anything extra inside Ubuntu to get it to allow outside connections to go to my containers?

EDIT: I'm also just using the official Jenkins image from docker hub.

Answer 1

If you are running this:

docker run -p 8080:8080 jenkins

Then to connect to jenkins you will have to connect to (in essence you are doing port forwarding):

http://127.0.0.1:8080 or http://localhost:8080

If you are just running this:

docker run jenkins

You can connect to jenkins using the container's IP

http://<containers-ip>:8080

The Dockerfile when the Jenkins container is built already exposes port 8080