Invalid HTTP_HOST header: 'localhost:90,localhost:90'. The domain name provided is not valid according to RFC 1034/1035

Question

I am trying to configure nginx along with Gunicorn for a Django project. nginx is giving me the following error:

DisallowedHost at /
Invalid HTTP_HOST header: 'localhost:90,localhost:90'. The domain name provided is not valid according to RFC 1034/1035.

This is my nginx configuration

    server {

        listen 90;
        listen [::]:90;

        server_name xxxx;

        location = /favicon.ico { access_log off; log_not_found off; }
        location /static/ {
            root /home/user/djangopro/djangoapp;
        }

        location / {
            include proxy_params;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Host $http_host;
            proxy_buffering off;
            proxy_redirect off;

            proxy_pass http://localhost:8200/;
        }
    }

Gunicorn is serving the site properly at localhost:8200. Can anyone tell me what is causing the error?

Answer 1

I was getting the same error. I'm guessing you might be coming from Flask converting to Django? If you remove the proxy_set_header Host $http_host; line from your configuration, it should work (it fixed my error). I think what that does is stack together both the requesting ip address, and the proxy ip address, while Django only wants a single ip address, not a list. See this Django ticket: https://code.djangoproject.com/ticket/28028

I'm guessing you already got this figured out (since its been a few months), but I'm still answering to save someone the 2 hours I just spent googling :)

edit: I'd like to clarify, the problem comes from having both include proxy_params; and proxy_set_header Host $http_host; set. The default proxy_params already have the proxy_set_header Host $http_host; included, so it'll set the host twice, hence the list of two hosts. Look at the proxy_params file in /etc/nginx/proxy_params if you're on Ubuntu (will be a similar path on other machines).