This content originally appeared on DEV Community and was authored by Sharon
Most developers assume that once a site is running on HTTPS, it’s “secure by default.”
Unfortunately, that’s far from the truth.
A misconfigured SSL/TLS setup can leave your website wide open to attacks — from outdated protocols that leak data, to weak ciphers that browsers don’t even trust anymore.
In this guide, we’ll break down how SSL/TLS really works, the common mistakes developers make, and the exact configurations you should be using in 2025 to keep your site secure, fast, and trusted.
What Is SSL/TLS?
SSL (Secure Sockets Layer) and its successor TLS (Transport Layer Security) are cryptographic protocols that encrypt the data transmitted between a user's browser and your server.
While SSL itself is outdated (TLS has replaced it), the term “SSL” is still widely used informally.
Whenever you see https:// in a URL and a padlock icon in the browser, you’re using TLS.
Why SSL/TLS Matters for Web Security
1. Data Confidentiality
All data sent between the client and server is encrypted, making it unreadable to attackers.
2. Data Integrity
TLS prevents tampering. If someone alters data mid-transit, the connection is dropped.
3. Authentication
TLS certificates prove that users are connecting to the real server — not a spoofed one.
4. Trust and SEO
Search engines rank HTTPS-enabled sites higher, and browsers show warnings on non-HTTPS pages.
How SSL/TLS Works
- Client Hello – The browser initiates a connection, listing supported TLS versions, cipher suites, and a random string.
- Server Hello – The server responds with its certificate, chosen cipher, and its own random string.
- Certificate Validation – The browser checks if the certificate is valid, trusted, and not expired.
- Key Exchange – Both sides perform a handshake to establish a shared session key.
- Encrypted Communication – All further data is encrypted using that session key.
This entire process takes milliseconds — invisible to end users, but critical for security.
How to Configure SSL/TLS the Right Way
1. Get a Valid Certificate
Use providers like DigiCert or GlobalSign, or a free option like Let’s Encrypt.
Let’s Encrypt is widely used for small and medium sites.
Example (Ubuntu + Nginx with Certbot):
sudo apt install certbot python3-certbot-nginx
sudo certbot --nginx
2. Redirect All Traffic to HTTPS
Force users onto HTTPS to prevent unencrypted access.
Nginx Example:
server {
listen 80;
server_name yourdomain.com;
return 301 https://$host$request_uri;
}
3. Use Strong TLS Settings
Disable insecure protocols like SSLv3, TLS 1.0, and TLS 1.1. Stick to TLS 1.2 and TLS 1.3.
ssl_protocols TLSv1.2 TLSv1.3;
ssl_ciphers HIGH:!aNULL:!MD5;
ssl_prefer_server_ciphers on;
4. Enable HTTP Strict Transport Security (HSTS)
Force browsers to always use HTTPS — even if the user types http://.
add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
5. Automate Certificate Renewal
Certificates expire. Automate renewal to avoid downtime.
Let’s Encrypt Example:
# Test auto-renewal
sudo certbot renew --dry-run
# Add to crontab (runs twice daily)
0 */12 * * * certbot renew --quiet
Testing Your SSL/TLS Setup
Use these free tools to audit your site:
- SSL Labs – Full TLS/SSL configuration test.
- securityheaders.com – Checks your headers for missing protections.
Both will give you a score and show exactly where your setup can be improved.
Summary
HTTPS isn’t optional in 2025 — it’s the baseline for trust and security.
But simply enabling it isn’t enough.
To stay secure:
- Use TLS 1.2 or 1.3 only.
- Automate certificate renewals.
- Enforce HTTPS everywhere with redirects and HSTS.
Done right, SSL/TLS keeps your users safe, your app credible, and your SEO ranking strong.
Don’t just turn on HTTPS — configure it correctly.
Join the SafeLine Community
If you continue to experience issues, feel free to contact SafeLine support for further assistance.
This content originally appeared on DEV Community and was authored by Sharon
Sharon | Sciencx (2025-09-18T07:25:49+00:00) Why Your HTTPS Setup Might Still Be Insecure (and How to Fix It). Retrieved from https://www.scien.cx/2025/09/18/why-your-https-setup-might-still-be-insecure-and-how-to-fix-it/
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