How to Generate a CSR for Wildcard Certificates (*.yourdomain.com)

A Wildcard SSL Certificate allows you to secure multiple first-level subdomains under a single main domain name, such as blog.yourdomain.com, shop.yourdomain.com, and mail.yourdomain.com.

To request a Wildcard SSL certificate, enter the domain name in wildcard format, such as *.yourdomain.com, in the Common Name (CN) field.

This guide explains how to properly format and generate a Wildcard CSR across common control panels and command-line environments.

The Fundamental Rule of Wildcard CSRs

When generating a standard SSL CSR, the Common Name (CN) field contains your exact domain name (e.g., example.com or [www.example.com](https://www.example.com)).

For a Wildcard SSL certificate, enter the Common Name (CN) in wildcard format, such as *.yourdomain.com.

Common Name (CN): *.yourdomain.com

(Replace yourdomain.com with your actual root domain name)

Option 1: Generate via BuySSL.lk Client Area (Easiest Method)

1. Log in to your BuySSL Client Area account.

2. Navigate to the CSR Generator tool inside your dashboard.

3. In the Common Name / Domain field, enter *.yourdomain.com.

4. Fill in your business name, city, province, and country code.

5. Click Generate CSR.

6. Important: Copy and securely save the generated Private Key text. The system will automatically use the CSR for your order configuration.

Option 2: Generate in cPanel

1. Log in to cPanel and open SSL/TLS under the Security section.

2. Click Generate, view, or delete SSL certificate signing requests.

3. Under Domains, type: *.yourdomain.com.

4. Fill in your City, State, Country, and Company details.

5. Set Key Length to 2,048 bits.

6. Click Generate.

7. Copy the generated CSR code block (including -----BEGIN CERTIFICATE REQUEST----- and -----END CERTIFICATE REQUEST-----).

Option 3: Generate in Plesk Control Panel

1. Log in to Plesk and go to Websites & Domains > SSL/TLS Certificates.

2. Click Add SSL/TLS Certificate.

3. In the Domain Name field, enter: *.yourdomain.com.

4. Fill out the required organization and location details.

5. Select 2048 bits key length and click Request.

6. Click on the newly created record and copy the text inside the CSR field.

Option 4: Generate via Linux Terminal (OpenSSL)

1. Connect to your server via SSH.

2. Run the following OpenSSL command:

   Bash

   openssl req -new -newkey rsa:2048 -nodes -keyout wildcard_yourdomain.key -out wildcard_yourdomain.csr

3. When prompted for Common Name (e.g. server FQDN), type: *.yourdomain.com

   Plaintext

   Country Name (2 letter code) [AU]: LK State or Province Name (full name) []: Western Province Locality Name (eg, city) []: Colombo Organization Name (eg, company) []: Example Lanka Pvt Ltd Organizational Unit Name (eg, section) []: IT Common Name (e.g. server FQDN) []: *.yourdomain.com

4. Display and copy your CSR:

   Bash

   cat wildcard_yourdomain.csr

Option 5: Generate in Windows IIS (IIS 8 / 10)

1. Open IIS Manager > select Server Name > double-click Server Certificates.

2. Click Create Certificate Request... in the Actions pane.

3. In the Common Name field, enter: *.yourdomain.com.

4. Complete the remaining wizard fields (Bit length: 2048).

5. Save the CSR file to your server drive, open it with Notepad, and copy the text.

Submitting Your Wildcard CSR

1. Return to my.buyssl.lk > Services > My Services.

2. Select your active Wildcard SSL order and click Configure Certificate.

3. Paste the copied Wildcard CSR into the configuration box.

4. Select your web server software and proceed to validation.

Pro-Tips & Important Notes:

• First-Level Subdomains Only: A wildcard certificate for *.yourdomain.com secures first-level subdomains such as blog.yourdomain.com and shop.yourdomain.com, but it does not secure deeper subdomains such as dev.blog.yourdomain.com.

• Base Domain Protection: A wildcard certificate for *.yourdomain.com does not automatically secure the base domain yourdomain.com. If you need to secure both, make sure yourdomain.com is also included in the certificate.

• Validation Method Requirement: Wildcard certificates commonly require DNS-based validation, such as a DNS TXT or CNAME record. The exact validation method depends on the Certificate Authority and certificate product.