Configuring TLS

Modern TLS without the guesswork

Enable HTTPS with listen 443 ssl;, a certificate chain in ssl_certificate (your certificate followed by intermediates) and the private key in ssl_certificate_key, readable only by root. Restrict protocols to TLSv1.2 TLSv1.3; older versions are insecure and disabled by modern browsers. For TLS 1.2, use strong cipher suites (Mozilla's SSL Configuration Generator publishes recommended "intermediate" settings); TLS 1.3 cipher suites are fixed and secure by default. Enable a session cache (ssl_session_cache shared:SSL:10m;) so returning clients resume sessions cheaply. Obtain free, automatically renewed certificates from Let's Encrypt with Certbot or another ACME client; renewals run on a timer and reload NGINX afterwards. Test your configuration with an external scanner such as SSL Labs, and monitor certificate expiry, because an expired certificate is a complete outage for users.

Terminating TLS at the edge

NGINX decrypts HTTPS from clients and talks to applications on the internal network.

An HTTPS server with Let's Encrypt certificates

Protocols, session cache and certificate paths as created by Certbot.

server {
    listen 443 ssl;
    listen [::]:443 ssl;
    http2 on;                                   # NGINX 1.25.1+ syntax
    server_name shop.example.com;

    ssl_certificate     /etc/letsencrypt/live/shop.example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/shop.example.com/privkey.pem;
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_prefer_server_ciphers off;               # let modern clients choose
    ssl_session_cache shared:SSL:10m;
    ssl_session_timeout 1d;

    location / { proxy_pass http://app_backend; }
}

# obtain and install a certificate, then renew automatically:
# sudo certbot --nginx -d shop.example.com
# sudo certbot renew --dry-run

Serve the full chain

Using only the leaf certificate works in some browsers (which fetch intermediates) and fails in others, especially API clients. Always configure the full chain (fullchain.pem with Certbot).

त्वरित जाँच: Which TLS protocol versions should a modern NGINX configuration allow?

• TLSv1.2 and TLSv1.3
• SSLv3 and TLSv1.0
• TLSv1.0 through TLSv1.3
• Only TLSv1.1