Nginx中的HSTS：是否应该在子域服务器块中添加Strict-Transport-

让我们将以下nginx.conf配置文件与example.com和subdomain.example.com的服务器块一起使用：

http {
    ...

    server {
        listen [::]:80 ipv6only=off default_server;
        server_name example.com;
        return 301 https://example.com$request_uri;
    }
    server {
        listen [::]:443 ipv6only=off ssl default_server;
        server_name example.com;
        add_header Strict-Transport-Security
            "max-age=63072000; includeSubDomains; preload" always;
        ...
    }

    server {
        listen [::]:80 ipv6only=off;
        server_name subdomain.example.com;
        return 301 https://subdomain.example.com$request_uri;
    }
    server {
        listen [::]:443 ipv6only=off ssl;
        server_name subdomain.example.com;
        add_header Strict-Transport-Security
            "max-age=63072000; includeSubDomains; preload" always; # <-- again ???
        ...
    }
}

标题的includeSubDomains部分显然告诉浏览器标题也适用于所有子域.

但是,如果该浏览器在看到example.com之前访问了subdomain.example.com,那将不会有任何帮助,是吗？因此,为了涵盖这种情况,我需要在所有子域服务器块中添加相同的add_header …对吗？