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How to Generate a CSR for a Wildcard SSL Certificate

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Your guide to generating a Wildcard CSR on any server

Your Certificate Signing Request (CSR) is more or less an application for an SSL certificate. You can’t get an SSL certificate issued without one. A CSR is an encoded file that offers you a standardized way to send Comodo your public key and some information about your company or organization. Generating a CSR for a Wildcard SSL certificate is extremely similar to generating a CSR for any other SSL certificate, with one key difference: the asterisk.

Before you start

Wildcard SSL Certificate
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Filling out your CSR

cPanel wildcard ssl certificate csr

The CSR form in cPanel includes instructions for generating a wildcard certificate CSR.

Here’s the information you’ll need to fill out in your Certificate Signing Request for your Wildcard SSL CSR:

  • Common Name (CN) – Your fully-qualified domain name goes here.
  • Organization Name (O) – The legal name of your company or organization
  • Organization Unit (OU) – What department or division of your company are you?
  • Locality (L) – The city your company or organization resides in.
  • State or Province (ST) – The state or province your company or organization resides in.
  • Country (C) – The country your company or organization resides in.
  • Email Address – Self-explanatory
  • Root Length – Typically 2048-bit
  • Signature Algorithm – SHA-2

What’s this about an asterisk?

Here’s the difference between a Wildcard CSR and a regular CSR, with the Wildcard you place an asterisk at the sub-domain level you’re attempting to encrypt (typically first-level) in your FQDN. For instance, if was going to install a Wildcard, our input in the Fully-Qualified Domain Name field would be:


As long as you use the asterisk, your Wildcard will work correctly and encrypt your domain, plus all of its accompanying sub-domains. No limit. If you have one-million sub-domains, your Wildcard will cover all of them. And if you ever add another one during the Wildcard’s lifespan, just re-issue it and it’ll cover the new one, too.

Generate a Wildcard SSL CSR on your Server

Each server software has a slightly different way for you to generate your certificate signing request (CSR). Here are instructions for generating a wildcard certificate CSR for all of the most common platforms.

Microsoft IIS



Microsoft Exchange

Microsoft Office Communications

F5 Big IP

Web Host Manager

Amazon Web Services


Media Temple





Jetty Java

If your server isn’t on this list, you may need to browse around your control panel or contact your web host support. Remember generating a wildcard certificate CSR is just like generating a standard CSR – you just need to add the *. before your domain!

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Comodo SSL Certificates

Tip: You can typically save a significant amount by buying your SSL certificate direct instead of through your web hosting company. We sell all Comodo SSL certificates at up to 75% off.