The X-Forwarded-For (XFF) header identifies the originating IP address of a user through an HTTP proxy or load balancer. When using Ezoic's platform, requests from your users will be routed through Ezoic's Amazon Cloud Servers (AWS). Therefore, your logs will show Ezoic IP addresses rather than the original IP address of the user.
Many web applications use the origin IP address of the user. For example, users can be identified by their IP address when logging into a member area. In this case, it's a good idea to pass along the origin IP.
Another issue that can arise when using a proxy or load balancer is that your hosting company detects an 'attack' because all the requests are coming from a single or few IPs rather than a wide assortment. This can be fixed by using the XFF header as well.
By implementing the XFF header, Ezoic will send the IP address of the original web visitor through to your server in the X-Forwarded-For header.
In PHP it is available in: $_SERVER['HTTP_X_FORWARDED_FOR']
In .NET its available in HttpContext.Current.Request.Headers["X-Forwarded-For"]
For more information, please see this article.