如何配置独立的 nginx 反向代理服务器来处理到在 apache 上运行 wordpress 的独立机器的 SSL 流量？

Question

如何创建与我的 apache 2 网站的安全连接？

revProxy server xyz.com.conf
# Redirect HTTP requests to HTTPS
server {
    listen 80;
    server_name  xyz.com www.xyz.com;
    return 301 https://$host$request_uri;
}

# For ssl
server {
    ssl on;
    ssl_certificate /etc/letsencrypt/live/xyz.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/xyz.com/privkey.pem;
    ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
    ssl_prefer_server_ciphers on;
    ssl_dhparam /etc/ssl/certs/dhparam.pem;
    ssl_ciphers 'ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDH$';
    ssl_session_timeout 1d;
    ssl_session_cache shared:SSL:50m;
    ssl_stapling on;
    ssl_stapling_verify on;
    add_header Strict-Transport-Security "max-age=15768000";

    default_type  application/octet-stream;

    listen 443;
    server_name  xyz.com www.xyz.com;

    root /var/www/xyz.com;

    location ~ /.well-known {
        allow all;
    }

    location / {
        include proxy_params;
        proxy_pass http://192.168.1.4;
    }
}

此 nginx 服务器块不安全。如何创建到两个 wordpress 站点的安全连接？