问题
In some requests the $_SERVER['HTTP_HOST'] not exists. I researched on the causes and now I know that this occurs on HTTP 1.0 requests.
I have 4 domains in many machines behind a load balancer on AWS EC2 and I don't have a idea how to solve this problem.
This is important, because is a business rule.
来源：https://stackoverflow.com/questions/24044630/http-host-not-found-behind-load-balancer-on-ec2