How to test a server with a request without the “Host” header field

Question

I have a server that is using Nginx's 444 to drop connections to undefined hosts:

server {
    listen      80;
    server_name "";
    return      444; 
}

But I can't figure out how to test if it's working.

Here are a few things I've tried, stabbing in the dark:

$ curl -I mysite.com --header 'Host: ""'
HTTP/1.1 301 Moved Permanently

$ curl -I mysite.com --header ''
HTTP/1.1 301 Moved Permanently

I'm trying to get that 444!

Here's the relevant portion of my nginx mysite.conf file

server {
    listen 80;
    server_name "";
    return 444;
}

server {
    listen 80 default_server;
    listen [::]:80 default_server;
    server_name _;
    return 301 https://$host$request_uri;
}

So either I'm testing it wrong, or I'm testing it correctly but the missing host header is still getting captured by my second server block and redirecting.

Answer 1

This works with curl 7.47:

curl -I --header Host: mysite.com

Note that the argument to the header option is just Host: ('Host: ' and 'Host: ""' won't work)

Latest versions of curl may have a --http0.9 option that may get you the same result, but I didn't test it.