Installation of Wildcard SSL on Multiple Servers

If your site runs across several subdomains like blog.yoursite.com, shop.yoursite.com, or mail.yoursite.com, managing separate SSL certificates for each can get messy fast. The good news? There’s a cleaner way to handle it.

A Wildcard SSL certificate simplifies things by letting you secure all your subdomains with one certificate. And yes, you can install it on multiple servers too. In this guide, I’ll show you exactly how to do that whether your subdomains live on one server or many.

What’s a Wildcard SSL Certificate?

A Wildcard SSL is a special kind of certificate designed to secure your main domain and any number of subdomains as long as they’re at the same level.

For example, if you register a certificate for *.yoursite.com, it will cover:

blog.yoursite.com

store.yoursite.com

login.yoursite.com

and so on...

This makes Wildcard SSL for subdomains an excellent choice for growing websites and businesses with several services or platforms running under one domain umbrella.

Can You Use the Same Certificate on Multiple Servers?

Yes, you can and should, if you’re managing different subdomains across different server systems. As long as you have access to the certificate and the private key, you’re good to go. The process is simple, but you do need to pay attention to how you export, transfer, and secure those files.

Step-by-Step: How to Install a Wildcard Certificate on Multiple Servers

Let’s walk through the whole process from generating the certificate to getting it set up on multiple servers.

1. Generate a CSR (Certificate Signing Request)

This is the first step in getting any SSL certificate. The Certificate Signing Request (CSR) contains the details of your domain and public key, which you’ll send to the Certificate Authority (CA).

On Linux

Run this OpenSSL command:

openssl req -new -newkey rsa:2048 -nodes -keyout wildcard.yoursite.com.key -out wildcard.yoursite.com.csr

When prompted for the “Common Name,” enter: *.yoursite.com

This creates:

• A .csr file to submit to the CA
• A .key file — your private key (don’t share this!)

On Windows (IIS)

• Open IIS Manager
• Go to Server Certificates
• Click Create Certificate Request
• Enter *.yoursite.com as the common name
• Save the CSR file when you’re done

2. Get Your Wildcard SSL Certificate

Send the CSR to your SSL provider (like Sectigo, ClickSSL, DigiCert, or Comodo). After they validate your request, they’ll send you the certificate files, usually your domain certificate and a CA bundle.

3. Install the Certificate on the First Server

For Linux (Apache or Nginx):

Save your certificate, private key, and CA bundle to your server, then update your server block or virtual host config. Example for Nginx:

nginx

server {

listen 443 ssl;

server_name *.yoursite.com;

ssl_certificate /etc/ssl/certs/wildcard.crt;

ssl_certificate_key /etc/ssl/private/wildcard.key;

ssl_trusted_certificate /etc/ssl/certs/ca_bundle.crt;

}

For Windows (IIS):

• Go to Server Certificates in IIS
• Select Complete Certificate Request
• Upload your .cer file
• Bind it to the correct site on port 443

4. Export the Certificate with the Private Key

To use the same certificate on other servers, you’ll need to export it as a .pfx file, which bundles the certificate, private key, and CA chain into one file.

On Linux:

openssl pkcs12 -export -out wildcard.pfx -inkey wildcard.key -in wildcard.crt -certfile ca_bundle.crt

On Windows:

• Open MMC > Certificates
• Find your wildcard certificate
• Right-click > All Tasks > Export
• Choose to export with the private key and save as .pfx

5. Install on Your Other Servers

Now take that .pfx file and copy it securely to your other servers.

On Windows:

• Use the Import Certificate option in IIS

On Linux:

If needed, convert .pfx back into .key and .crt:

openssl pkcs12 -in wildcard.pfx -clcerts -nokeys -out wildcard.crt

openssl pkcs12 -in wildcard.pfx -nocerts -out wildcard.key

Make sure you protect your key file. Restrict access and avoid storing it in public or shared directories.

Tips for Managing Wildcard SSLs Across Servers

• Transfer securely: Always use SCP, SFTP, or other encrypted methods when moving .pfx or .key files.
• Track where it’s installed: Keep a list of all servers using the wildcard cert helpful when it’s time to renew.
• Automate the process: If you’re managing a fleet of servers, tools like Ansible or Chef can simplify deployments and updates.

Wrapping Up

Installing a Wildcard SSL on multiple servers isn’t hard once you understand the workflow. With a single certificate, you can secure all your subdomains; no need to manage dozens of certs or repeat the setup process over and over.

Whether you’re running a few subdomains or dozens, using a Wildcard SSL certificate saves time, cuts down on confusion, and keeps your web traffic safe.

Need help choosing the right wildcard SSL cert? Read the mentioned guide here: Wildcard SSL Certificate: A Quick Guide