Should I block HTTP 1.0 request? [closed]

Question

I use $_SERVER['HTTP_HOST'] for absolute url paths in my website. But, often, I find nginx error logs of HTTP/1.0 requests with undefined HTTP_HOST.

Is it advisable to block these requests? What's the best way to block them?

Answer 1

Is it advisable to block these requests?

If your application cannot serve anything meaningful without the host, then it's IMO advisable. Furthermore I couldn't find anything in HTTP 1.1 which says applications have to be backward compatible.

What's the best way to block them?

Answer them with 505 HTTP Version Not Supported.