[django] CommandError: You must set settings.ALLOWED_HOSTS if DEBUG is False

I'm using Django 1.6.5 with the setting:

DEBUG = True

When I change to DEBUG = False and run manage.py runserver, I get the following error:

CommandError: You must set settings.ALLOWED_HOSTS if DEBUG is False

I get the same error with the following setting:

ALLOWED_HOSTS = ['127.0.0.1', 'localhost']

How can I fix this?

If you work in PyCharm, check the Environmental variables for your Django server. You should specify the proper module.settings file

Try

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True

ALLOWED_HOSTS = ['*']

A value of '*' will match anything; in this case you are responsible to provide your own validation of the Host header.

Make sure it's not redefined again lower down in your settings.py. The default settings has:

ALLOWED_HOSTS = []

Your solution might be to add the original IP and/or hostname also:

ALLOWED_HOSTS = [
  'localhost',
  '127.0.0.1',
  '111.222.333.444',
  'mywebsite.com']

The condition to be satisfied is that the host header (or X-Forwarded-Host if USE_X_FORWARDED_HOST is enabled) should match one of the values in ALLOWED_HOSTS.

Try

ALLOWED_HOSTS = ['*']

Less secure if you're not firewalled off or on a public LAN, but it's what I use and it works.

EDIT: Interestingly enough I've been needing to add this to a few of my 1.8 projects even when DEBUG = True. Very unsure why.

EDIT: This is due to a Django security update as mentioned in my comment.

I also experienced this cmderror. After trying all the answers on here, I couldn't still figure out the problem, here is what I did:

1. Cd into the project directory. e.g cd project-dir
2. I migrated. e.g python manage.py migrate
3. I created a super user. e.g python manage.py createsuperuser
4. Enter the desired info like username, password, email etc
5. You should get a "super user created successfully" response
6. Now run the server. E.g python manage.py runserver
7. Click on the URL displayed
8. The URL on your browser should look like this, 127.0.0.1:8000/Quit
9. Now edit the URL on your browser to this, 127.0.0.1:8000/admin
10. You should see an administrative login page
11. Login with the super user info you created earlier on
12. You should be logged in to the Django administration
13. Now click on "view site" at the top of the page
14. You should see a page which shows "the install worked successfully..... Debug = True"
15. Voila! your server is up and running

This works for me:

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = False

ALLOWED_HOSTS = ['localhost', '127.0.0.1']

Use this:

ALLOWED_HOSTS =  ['localhost', '127.0.0.1']

Just simply comment out the line: ALLOWED_HOSTS = [...]

From documentation: https://docs.djangoproject.com/en/1.10/ref/settings/

if DEBUG is False, you also need to properly set the ALLOWED_HOSTS setting. Failing to do so will result in all requests being returned as “Bad Request (400)”.

And from here: https://docs.djangoproject.com/en/1.10/ref/settings/#std:setting-ALLOWED_HOSTS

I am using something like this:

ALLOWED_HOSTS = ['localhost', '127.0.0.1', 'www.mysite.com']