unable to access django development server on firefox/chrome

hi

I have just started to learn django. so I followed the instruction given in the link below. I am using ubuntu 13.04 and using python 3.3.1 in a virtual environment

https://docs.djangoproject.com/en/1.5/intro/tutorial01/

I ran the following command

python manage.py runserver

it gave the following output

Validating models...

0 errors found
October 12, 2013 - 11:37:58
Django version 1.5.4, using settings 'mywebsite.settings'
Development server is running at http://127.0.0.1:8000/
Quit the server with CONTROL-C.

But I am unable to access the url http://127.0.0.1:8000/ on firefox. It says unable to connect

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