How to Install a Wildcard SSL Certificate for Multiple Subdomains

How to Install a Wildcard SSL Certificate for Multiple Subdomains

A Wildcard SSL certificate allows you to secure a primary domain and unlimited subdomains using a single certificate. This makes it ideal for websites with multiple environments such as blog.domain.com, shop.domain.com, api.domain.com, or staged development sites. At QuickServers, our integrated SSL management system makes it easy to activate, install, and manage your Wildcard SSL certificate so every subdomain stays protected under HTTPS.

This guide explains what a Wildcard SSL is, how it works, and how you can install it on your server.

Understanding How Wildcard SSL Certificates Work

A Wildcard SSL certificate secures one root domain and all subdomains at the same level using a single certificate.
For example:

Secures:

• *.yourdomain.com

• blog.yourdomain.com

• mail.yourdomain.com

• store.yourdomain.com

Does NOT secure:

• sub.blog.yourdomain.com

• sub.store.yourdomain.com

Wildcard SSL certificates dramatically simplify SSL deployment and reduce the need to install individual certificates for each subdomain.

Prerequisites Before Installation

Before installing your Wildcard SSL certificate, make sure you have:

• A fully activated Wildcard SSL certificate issued to *.yourdomain.com

• The private key generated during CSR creation

• Your certificate file and CA bundle

• Access to your hosting control panel or server

• DNS pointed correctly to your hosting environment

If you generated your CSR and activated your Wildcard certificate through QuickServers, you can download these files safely from your SSL management dashboard.

Step 1: Generate a CSR Using the Wildcard Format

When creating your CSR, the Common Name (CN) must be:

*.yourdomain.com

This ensures that all subdomains are covered under the same SSL certificate.

Information you’ll need:

• Common Name: *.yourdomain.com

• Organization: Your business name

• City, State, Country

• Key size (minimum 2048-bit)

Once the CSR is generated, save the corresponding private key securely. You’ll need it during installation.

Step 2: Download Your SSL Certificate Files

After the certificate is issued through your QuickServers SSL dashboard, download:

• The Wildcard certificate file (*.crt)

• The private key (*.key)

• The CA bundle or intermediate certificate

Keep these files organized so you can upload them to your server.

Step 3: Upload the Certificate Files to Your Server

Depending on your hosting environment, upload the following files to the appropriate directory:

• Wildcard certificate: yourdomain_wildcard.crt

• Private key: yourdomain_wildcard.key

• CA bundle: ca_bundle.crt

Common directories include:

/etc/ssl/certs/
/etc/ssl/private/

Make sure your private key is protected with secure permissions.

Step 4: Configure Your Web Server

Depending on your server type, you’ll need to adjust configuration files to point to your new Wildcard SSL.

Apache Example:

SSLCertificateFile /etc/ssl/certs/yourdomain_wildcard.crt
SSLCertificateKeyFile /etc/ssl/private/yourdomain_wildcard.key
SSLCertificateChainFile /etc/ssl/certs/ca_bundle.crt

Nginx Example:

ssl_certificate /etc/ssl/certs/yourdomain_wildcard.crt;
ssl_certificate_key /etc/ssl/private/yourdomain_wildcard.key;
ssl_trusted_certificate /etc/ssl/certs/ca_bundle.crt;

Restart your server after saving:

Apache:

sudo systemctl restart apache2

Nginx:

sudo systemctl restart nginx

Step 5: Update All Subdomains to Use HTTPS

Once the Wildcard SSL is installed, update each subdomain to redirect HTTP traffic to HTTPS.

Examples:

Nginx Redirect:

return 301 https://$host$request_uri;

Apache Redirect:

RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

This ensures all subdomains load securely and benefit from your Wildcard SSL.

Step 6: Test Your Installation

Verify that each subdomain loads over HTTPS:

• https://blog.yourdomain.com

• https://store.yourdomain.com

• https://api.yourdomain.com

Check for:

• Padlock symbol in the browser

• No mixed-content warnings

• Correct certificate information (issued to *.yourdomain.com)

If something isn’t working, confirm that your server is using the correct certificate paths and that DNS for each subdomain is correctly configured.

Why Use Wildcard SSL with QuickServers

Wildcard SSL certificates offer several benefits for growing websites:

• Protect unlimited subdomains with one certificate

• Simplify SSL installation and management

• Reduce renewal complexity

• Strengthen SEO performance across all subdomains

• Prevent browser security warnings

• Ideal for multi-service business websites

QuickServers’ integrated SSL management system lets you activate, install, renew, and manage your Wildcard SSL certificates easily from your hosting account.

The Bottom Line

A Wildcard SSL certificate is the most efficient way to secure multiple subdomains under one simplified SSL setup. Whether you’re protecting a blog, storefront, mail server, or API endpoints, a Wildcard certificate ensures consistent encryption and trusted connections across your entire domain.

With QuickServers, installing and managing your Wildcard SSL is fast, secure, and fully optimized for modern hosting environments.