Accessing frappe bench from web browser

I just installed Frappe on my Ubuntu server. Then I successfully started the bench (bench start). It seems that frappe is correctly running on, indeed the command:
curl -I http://localhost:8000
HTTP/1.0 200 OK
Content-Type: text/html; charset: utf-8
Content-Length: 12562
X-Page-Name: login
X-From-Cache: False
Set-Cookie: sid=Guest; Expires=Thu, 11-Jun-2015 13:54:02 GMT; Path=/
Server: Werkzeug/0.10.4 Python/2.7.6
Date: Mon, 08 Jun 2015 06:54:02 GMT

But I get an unavailable page each time I try to connect to http://localhost:8000 from my browser (IE, Chrome or Firefox). the JavaScript console indicate the below error:
Failed to load resource: net::ERR_CONNECTION_REFUSED

Any idea how to fix that?

Hi everyone,
I think it was an issue with ufw rules. I made them again from scratch using this page as an help:

Now I can access Frappe desk!

Well done for solving it.
I’ll bookmark this page!