How to Install an SSL Certificate on nginx — 2026

Enterno.io Editorial Team

How to Install SSL on nginx

By Anatoly Oshmanovsky · Updated Apr 18, 2026

Key idea:

Installing SSL on nginx in 15 min with Let's Encrypt: certbot automatically modifies the config + enables HTTPS + adds HTTP→HTTPS redirect. For manual control — copy fullchain.pem + privkey.pem into /etc/ssl/, add an ssl block to the server config, enable HSTS + modern ciphers.

Below: step-by-step, working examples, common pitfalls, FAQ.

Try it now — free →

Step-by-Step Setup

Install certbot + plugin: apt install certbot python3-certbot-nginx
Ensure the domain resolves to the server (A record)
Auto-install: certbot --nginx -d example.com -d www.example.com
Certbot will ask about HTTP→HTTPS redirect (always yes)
Verify: curl -I https://example.com → HTTP/1.1 200 OK
Enable auto-renew: systemctl enable --now certbot.timer
Test: Enterno SSL → grade A+ with proper cipher suite

Working Examples

Scenario	Config
nginx ssl block (manual)	`server { listen 443 ssl http2; server_name example.com; ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem; ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem; ssl_protocols TLSv1.2 TLSv1.3; ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256; }`
HTTP→HTTPS redirect	`server { listen 80; server_name example.com; return 301 https://$host$request_uri; }`
HSTS header (preload-ready)	`add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" always;`
OCSP Stapling	`ssl_stapling on; ssl_stapling_verify on; ssl_trusted_certificate /etc/letsencrypt/live/example.com/chain.pem; resolver 1.1.1.1 valid=60s;`
Pre-installed cert (not Let's Encrypt)	`# cat cert.pem intermediate.pem > fullchain.pem ssl_certificate /etc/ssl/fullchain.pem; ssl_certificate_key /etc/ssl/private.key;`

Common Pitfalls

Using only cert.pem (no intermediate) → ERR_CERT_AUTHORITY_INVALID for clients
Missing OCSP Stapling → -10 points in Qualys SSL Labs grade
Weak ciphers (RC4, 3DES) → grade F + Chrome ERR_SSL_VERSION_OR_CIPHER_MISMATCH
HSTS without testing — if something breaks, clients are locked out for weeks
Port 80 closed by firewall — certbot renewal fails (HTTP-01 challenge)

CertificateExpiry, issuer, domains (SAN)

ChainIntermediate and root CA validation

TLS ProtocolTLS version and cipher suite

VulnerabilitiesHeartbleed, POODLE, weak ciphers

Why teams trust us

TLS 1.3

supported

Full

CA chain check

<2s

result

30/14/7

days-to-expiry alerts

How it works

Enter domain

TLS chain verified

Expiry date & vulnerabilities

What Does the SSL Check Cover?

SSL/TLS is the encryption protocol that protects data between the browser and server. Our tool analyzes the certificate, chain of trust, TLS version, and knownvulnerabilities.

Certificate Details

Issuer, validity period, signature algorithm, covered domains (SAN), and validation type (DV/OV/EV).

Chain of Trust

Full chain verification: from leaf certificate through intermediates to root CA.

TLS Analysis

Protocol version (TLS 1.2/1.3), cipher suites, Perfect Forward Secrecy (PFS) support.

Expiry Alerts

Set up a monitor — get Telegram and email alerts 30/14/7 days before expiration.

DV vs OV vs EV Certificates

DV (Domain Validation)

Confirms domain ownership only
Issued in minutes automatically
Free via Let's Encrypt
Suitable for most websites
Most common certificate type

OV / EV

Organization (OV) or Extended Validation (EV)
Issued in 1-5 business days
Costs $50 to $500/year
For finance, e-commerce, government sites
Increases user trust

Who uses this

DevOps

SSL certificate monitoring

Security

TLS config audit

SEO

HTTPS as ranking factor

E-commerce

customer trust

Common Mistakes

❌

Expired certificateBrowsers block sites with expired SSL. Set up auto-renewal or monitoring.

❌

Incomplete certificate chainWithout intermediate CA, some browsers and bots cannot verify the certificate.

❌

Mixed content on HTTPS siteHTTP resources on an HTTPS page — the browser lock icon disappears, reducing trust.

❌

Using TLS 1.0/1.1Legacy TLS versions have known vulnerabilities. Use TLS 1.2+ or 1.3.

❌

Domain mismatch in certificateThe certificate must cover all site domains, including www and subdomains.

Best Practices

✓

Set up auto-renewalLet's Encrypt + certbot with cron — certificate renews automatically every 60-90 days.

✓

Enable HSTSStrict-Transport-Security header forces browsers to always use HTTPS.

✓

Use TLS 1.3TLS 1.3 is faster (1-RTT handshake) and safer — legacy ciphers removed.

✓

Monitor expiration datesCreate a monitor on Enterno.io — get notified well before expiration.

✓

Verify chain after renewalAfter certificate renewal, confirm that intermediate certificates are installed.

Get more with a free account

SSL certificate monitoring, check history and alerts 30 days before expiry.

Learn more

Research

TLS 1.3 Adoption 2026: Growth Pace

Errors

Frequently Asked Questions

Is Let's Encrypt good for production?

Yes, 100%. Google, Facebook, Cloudflare use it. Only constraint: 90 days validity (auto-renew handles that).

How to install a commercial CA cert?

Same as manual: fullchain.pem = cert + intermediate, separate privkey.pem. In nginx — ssl_certificate + ssl_certificate_key.

Certbot edits my config — safe?

Yes. Certbot keeps a backup. You can revert: <code>cp nginx.conf.backup nginx.conf</code>.

How to auto-renew?

systemctl enable --now certbot.timer. Runs twice daily. Renew hook: <code>--deploy-hook "systemctl reload nginx"</code>.