adminWhat SSL and HTTPS Mean
SSL is the security layer that allows a website to use HTTPS. HTTPS encrypts the connection between the browser and the server so users can send and receive data more safely.
Where SSL Sits In The Stack
SSL usually sits at the web server layer. On a VPS running Nginx, the SSL certificate is configured inside the Nginx server block for the domain.
How HTTPS Works
When a browser connects to a website using HTTPS, the server presents a certificate. The browser checks whether the certificate is valid for the domain. If the certificate is trusted, the browser continues the connection securely.
Why SSL Breaks Websites
SSL problems often happen when DNS points to the wrong server, the certificate does not include the www version, the certificate has expired, port 80 is blocked, or Nginx points to the wrong certificate file.
How To Think About SSL
SSL is not only a security setting. It is part of the production routing system. A website with broken SSL may be technically online but unusable to visitors.
Infrastructure Layer
SSL / Security
Difficulty Level
Beginner
Core Concept
SSL allows a website to use HTTPS by proving domain ownership and encrypting browser-server traffic.
System Role
It protects the connection layer between visitors and the web server, usually through Nginx on a VPS.
How It Works
The browser connects to the HTTPS endpoint, Nginx presents the SSL certificate, the browser validates it, and the encrypted session continues if the certificate is trusted.
Connected Components
DNS, domain, Nginx, SSL certificate, Certbot, port 80, port 443, browser, redirect rules.
Common Failure Points
Expired certificate, missing www coverage, wrong DNS target, blocked port 80, failed renewal, bad certificate path, redirect loop after HTTPS enforcement.
Verification Method
Verify HTTPS for root and www, check certificate expiry, test Nginx config, confirm port 80 and 443 are reachable, and test renewal dry run.
Basic Commands
curl -I https://example.com;
openssl s_client -connect example.com:443 -servername example.com;
certbot certificates;
nginx -t;
systemctl status nginx