Behind_LB

Behind-LB is a very simple and efficient Django middleware to obtain the client IP address when the project runs behind a trusted load balancer.

It allows to specify the path that activate the middleware, for example / or /a/specific/path. The path must be specified in the variable BEHIND_LB_PATH in your settings.py.

It works with any load balancer that sends the public remote address in a fixed relative position in the header (first, second,... , last). For example, Amazon ELB puts it in the last position, Google Compute Load Balancer in the penultimate one. The position must be specified in settings.BEHIND_LB_POSITION.

Quick start

1. Install the package:

   pip install django-behind-lb

2. Just add django-behind-lb to your INSTALLED_APPS setting like this:

   MIDDLEWARE_CLASSES = (
       'behind_lb.middleware.BehindLB',
       ...
   

3. Configure the path and position in settings.py:

   BEHIND_LB_PATH = "/"
   BEHIND_LB_POSITION = -2 # For Google Compute Engine
   

4. Try it reading the default request.META['REMOTE_ADDR'] in a View class. It should read the real client IP.

Position options

The BEHIND_LB_PATH value specifies the position of the real IP address in the X-Forwarded-For header, where 0 is the first (or "left"), 1 the second, -2 the penultimate position and -1 the last one. Examples:

BEHIND_LB_POSITION =  0 # First

BEHIND_LB_POSITION = -2 # Next to last, for Google Compute Engine LB

BEHIND_LB_POSITION = -1 # Last, for Amazon EC2 LB

In Github

The code is available at https://github.com/APSL/django-behind-lb