sudo openssl dhparam -out /etc/ssl/certs/dhparam.pem 2048
ssl_dhparam /etc/ssl/certs/dhparam.pem; ssl_session_timeout 1d; ssl_session_cache shared:SSL:10m; ssl_session_tickets off; ssl_protocols TLSv1.2 TLSv1.3; ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384; ssl_prefer_server_ciphers on; ssl_stapling on; ssl_stapling_verify on; resolver 8.8.8.8 8.8.4.4 valid=300s; resolver_timeout 30s; add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always; add_header X-Frame-Options SAMEORIGIN; add_header X-Content-Type-Options nosniff;
References
https://linuxize.com/post/secure-nginx-with-let-s-encrypt-on-ubuntu-20-04/