What Is a Wildcard SSL Certificate and How It Works?

Security of your website is of great importance. When it comes to providing security for multiple domain names or subdomains, it seems a bit harder. In these situations, using wildcard SSL certificates is a good choice. In this article, we are going to help you understand what is a wildcard SSL certificate and how it can help you best. So, stay tuned!

What Is a Wildcard Certificate?

A multi domain wildcard SSL is something you would need most if you happen to own multiple domain names, subdomains, and multi-level subdomains. It is the most convenient way for organizations who want to secure their whole group and encrypt all transmitted information using one single certificate.

This certificate can offer strong protection as it comes with strong encryption that does not allow cyber attackers to intercept ongoing data between the server and the web browsers. Being a cost-saving certificate, you do not need to go after each SSL certificate to ensure the safety of the domain, but you will get the same SSL certificate for multiple domains and their subdomains as well.

How Do Wildcard SSL Certificates Work?

How Do Wildcard SSL Certificates Work?

One of the common questions that come to mind is how wildcard SSL certificates work. It became popular due to various reasons. One of the critical parts of this certificate is security. Earlier the HTTP website used to rule the web. Recently Google has declared that they see the HTTP domain as the “Non-Secure” website. Since Google has dropped the importance of HTTP, the web has changed completely. The majority of the websites depend on the Google Search traffic source. Since Google is not supporting the HTTP domains in the ranking, it has affected the millions of websites that don’t have active SSL certificates.



People who own multiple domains now have to upgrade the HTTP websites to HTTPS / SSL secure websites. The challenging part is to apply the SSL to all the domain names at once. Also, the cost is the biggest concern with SSL. If you have a domain name with multiple subdomains, you have to buy a separate SSL domain name for each subdomain that you have created.

The SSL cost goes drastically up for a single domain name. For small companies investing a huge amount in the SSL to keep their website secure would be a daunting task. The additional cost would affect the finance of the company.

As a solution, the multi-domain SSL certificates have been introduced to create a safety net for the domain owner who does not want to spend much but wants to apply the SSL to all the domain names they own. The below example will help you understand the situation better.

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Austin owns multiple domains with several subdomains. Now he wants to apply the SSL certificate on the main domain as well as all the subdomains.

  • www.domain.com
  • service.domain.com
  • product.domain.com
  • blog.domain.com
  • www.site.com
  • page.site.com
  • page1.site.com
  • page2.site.com


In the above example, Austin owns two primary domains with their subdomains as listed above. Now when Austin purchases the SSL Certificate for the website “www.domain.com, the SSL certificate will apply only to the main domain name. He cannot use the same SSL certificate to verify the subdomains “service.domain.com”, “product.domain.com” and “blog.domain.com”.

He has to purchase three additional SSL certificates, integrate them on the site and manage them regularly to keep them active. As you can see the cost has gone up for a single domain as soon as you apply for the SSL Certificate. Also, you have to spend more time managing the SSL certificate separately to all the individual domain names.

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This process of applying SSL/TLS is not fruitful for any business. Therefore, to mitigate the challenges, the wildcard SSL is introduced. It enables the domain owner to apply the single SSL Certificate to all the domain names at once. A single certificate is more than enough to activate the SSL on the domain as well as a subdomain. It drastically reduces the cost of the SSL certificate giving advantages to the domain owner.

Now with a multi-domain wildcard, Austin can apply the single SSL Certificate to all below domain names.

  • www.domain.com
  • service.domain.com
  • product.domain.com
  • blog.domain.com

Remember that the multi domain wildcard SSL certificate works only to the one unique domain name at the time. In the case of Austin, if he wants to apply the wildcard SSL to the other website “www.site.com”, he has to purchase another wildcard SSL certificate.

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Best Features

Multi-domain Wildcard SSL certificate is identical to the SSL/TLS certificate in terms of encryption.

  • It comes with the standard 256-bit strong encryption with a 2048-bit RSA signature key
  • Supports domain validation that is done within minutes. You do not have to wait for the validation period. The Organization validation is done in two to three days
  • A single certificate would be enough to power your domain with SSL/TLS facility. Additionally, you can apply the SSL to an unlimited number of subdomains
  • Every certificate will be SAN wildcard support enabled
  • Enjoy the site seal on your main domain as well as subdomains
  • Padlock icon enabled immediately after the verification is complete
  • The wildcard SSL is supported by all the major browsers
  • It is accessible on all mobile operating systems
  • Centralize management facility offers convenience to the domain owner
  • Enable the website security at an affordable price

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Benefits of a Wildcard SSL Certificate

Using one SSL certificate for multiple domains has several advantages. We mention some of the most important ones in the following:

1) Simplified Certificate Management

It is crystal clear that wildcard SSL management is a time-consuming task, wearisome work as you need to purchase single-domain SSL certificates for your websites and subdomains. You have to go through the tedious process of certificate signing request (CSR) generation, validation, and installation process multiple times. On the other hand with multi-subdomain SSL certificates, the enabling processes will be reduced to one, which can save you the trouble.

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2) Low Risk of Renewal Omission

Renewing your wildcard SSL certificate before it expires is kind of a crucial matter, and you should certainly make sure of it because if you don’t, there will be horrible consequences:

  1. Your website will immediately be vulnerable to cyber-attacks
  2. Browsers will receive a security warning page with a “SEC_ERROR_EXPIRED_CERTIFICATE” error message whenever they try to visit your website.

Let’s say you have multiple SSL certificates. In that case, you have to keep track of their expiry date, and when they do expire you’ll have to go through the renewal process separately for each one. With multi-domain wildcard certificate, you just need to remember one expiry date and you’ll go through the renewal process for just one certificate instead of multiple. Needless to say with multi domain certificates the risk of renewal lapse will be considerably reduced.

Should you think that remembering an expiry date is really a petty issue, then it is important that you know big organizations like Ericsson, LinkedIn, Cisco, and even the US government have forgotten to renew their security certificates in the past caused great peril and also affected their reputation.

3) Saving Cost

If you choose to purchase separate wildcard SSL certificates for all of your various domains and their subdomains, it’s going to cost you a considerable sum of money. You can always use a multi subdomain SSL certificate to save your money up to a great extent.

4) Users Trust

It’s evident that a secure website will have more traffic in comparison to an insecure one. It will be easier for the users to put their trust in your site as it has maximum encryption as well as business validation which depends on the certificate you choose. It is also a reassuring factor for your website’s reliability, which assures the users that your website is safe for online shopping and any other transactions.

Single Domain Certificate vs Wildcard SSL

Which one should you choose? We can discuss the distinguishing differences of multi domain SSL certificate vs wildcard to make this process more comprehendible for you.

Multi domain wildcard is also known as Subject Alternative Name (SAN) and Unified Communication Certificate (UCC). As the name fully suggests multi domain wildcard SSL certificates are to protect several Fully Qualified Domain Names (FQDN) which could be a top-level domain or a subdomain as well and all with a single certificate.

Whilst issuing a wildcard SSL certificate, the user must distinctly define all of the domains that they would like the certificate to cover. Limitations on the number of domains covered by the multiple domain SSL certificates are determined by the issuing Certificate Authority as it can secure multiple domains up to a specific amount (i.e. 100). If a domain has to be added during an existing validity, the wildcard multi domain certificate should be reissued.

On the other hand, wildcard SSL allows users to acquire a certificate for a single domain. Now the user has to purchase the SSL certificate for the primary domain and all of the subdomains will be covered automatically. Here is an example to make this process clear. A wildcard SSL certificate which is issued for *.domain.com will protect the blog.domain.com, store.domain.com, etc. Although you would need an additional certificate to cover a second-level subdomain, such as dev.blog.domain.com. Wildcard SSL cert can secure a boundless amount of subdomains at only one specific subdomain level.

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How to Configure a Multi Domain Wildcard Certificate?

The process of multi domain wildcard is somewhat different from the usual drill but nothing that you can’t handle. The very first step is to create a CSR (Certificate Signing Request) for a single domain. Dissimilar to the Wildcard SSL certificate where you have to add an asterisk in front of the FQDN (fully-qualified domain name), here you just need to put your main domain (e.g., yourdomain.com). In the further SANs fields below the main domain, you must enter your Wildcard domains. Generally speaking, multi-domain wildcard SSL comes with 3SANs by default but you can add up250 SANs at the checkout page based on your needs.

Here’s what you can secure with the default configuration of 3 SANs certificate

A single main domain and several Wildcard domains. For example:


  • *.mydomain.com
  • *.mysecondomain.com

A single primary domain and innumerable Wildcard domains (with both first-level and second-level subdomains). For example:


  • *.mydomain.com
  • *.news.mydomain.com

Things To Consider When Activating the Certificate


Things To Consider When Activating the Certificate 1) Common Name (CN) Domain

The wildcard version you apply for should have a SAN.


Common Name: www.abc.com

  • SAN1 : *.abc.com
  • SAN2: *.site.com
  • SAN3. *.dev.site.com

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2) Domain Name Visibility

In the default settings, it keeps the list of the domain together. It means the domains available on the same certificate will be visible to the visitors. You cannot hide the other sites verified on the same multi domain wildcard certificates. If you do not want your visitors to view the other domain name, then this option is not suitable for you.

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3) WWW vs Non-WWW Domains

The www and non-www domains are treated differently. The certificate will not apply the SSL to the non-www domain version automatically when you’re using the wildcard SSL.

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Frequently Asked Questions

Can I Use SSL Certificate on Multiple Domains?

Definitely yes, you can either use a single SSL certificate for multiple domains or one SSL certificate for multiple subdomains as well as domains.


How Much Does a Wildcard SSL Certificate Cost?

The wildcard SSL certificate price significantly depends on your needs and it is mainly based on the level of your industry. The lowest price would be $69.78/year and the highest which is for large companies would be $1,018.42/year. Warranty is another matter you need to attend to as the warranty payments vary from $10,000 to $1,500,000 based on your business level of course.



Final Words

Through the years Cybercrime couldn’t be stopped as its onward march doesn’t seem like it will be stopping any time soon. On the authority to recent reports, cyber-attacks have increased by 100% from 2015 to 2017, and they continue to do so even now. Therefore Google has encouraged all websites to use SSL certificates to switch to HTTPS to make this fight fair and square as we enhance our website’s security to their highest level.

As we talked about SSL certificates, it has been mentioned that multi domain wildcard cert would be your best choice of safety as it could cover multiple FQDNs and subdomains, unlike a wildcard SSL certificate. Not to mention that multi-subdomain SSL certificate is much more efficient and less time-consuming. For more information about the difference between multi-domain wildcard SSL certificates and other SSL certificates, click here .

Hope the content has helped you to find out the answer to the question “what is multi domain Wildcard SSL” and how it will benefit you in the business.

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