Django ALLOWED_HOST setting for Elastic beanstalk instance behind Elastic Load Balancer

There is no good reason to accept traffic that is directed to your ELB's IP. For the health check, my preferred method:

import requests
try:
    internal_ip = requests.get('http://instance-data/latest/meta-data/local-ipv4').text
except requests.exceptions.ConnectionError:
    pass
else:
    ALLOWED_HOSTS.append(internal_ip)
del requests

• No complicated apache configuration, which depend on your domain
• Fails quickly on dns, no need to rely on timeout

I believe the best approach would be to configure Apache to handle request host validation. Even with beanstalk you should be able to configure Apache using .ebextensions.

The general idea is to check incoming requests for the 'ELB-HealthChecker/1.0' User-Agent and the health check URL you set as the request's REQUEST_URI. Those requests can have their host header changed to an allowed host with the RequestHeader set Host command.

If really don't want to configure Apache, you could implement a custom middleware to override Django's CommonMiddleware to allow the health checker requests to bypass Django's ALLOWED_HOST validation.

I went into greater detail in this answer if you need more on implementing one of these solutions.