Which Kind of SSL Is Best for Multiple Subdomains?

It’s not uncommon for website owners to have multiple subdomains these days. Maybe your development team has several subdomains set aside for website and application testing environments. Or maybe you use them for your website’s blog, payment page, or email. Whatever the case may be, you need an SSL certificate to ensure your domain and subdomains are as secure as possible. But which one is the right one for you? With so many different types of SSLs available, it can be hard to decide which one is most suitable for your website situation.

Which SSL you choose will depend on how many primary domains with subdomains you have. To secure numerous subdomains, you essentially have two options: a Multi-domain SSL and a Wildcard SSL certificate. Let’s talk about the difference between these two SSL types and how to know which is most suitable for you.

Multi-Domain SSL

  • Can secure multiple primary domains and subdomains
  • Usually a limited number (exact number depends on the Certificate Authority issuing it)
  • The domains you wish to secure must be defined before the certificate is issued. If you wish to add further domains or subdomains, you’ll need to get the SSL certificate reissued

Wildcard SSL

  • Secures a single domain and multiple subdomains (e.g. *.arandomsite.com) connected to it
  • No limit to the number of subdomains you can secure
  • You can even add more subdomains later, without having to get the certificate reissued

As you can see, a Multi-Domain SSL certificate will protect numerous primary domains and their subdomains, while a Wildcard Certificate will protect a single domain and the subdomains associated with that. Both have their limitations: with a multi-domain SSL, you have to know exactly which domains you wish to protect from the outset, and that number is limited. With a Wildcard Certificate you are limited to one primary domain. However, apart from that, a Wildcard Certificate is very flexible, as you can add as many subdomains to it as you like, at any time. So you are not limited to the number of subdomains you happen to have at the time of purchase.

If you already have a lot of different websites with multiple subdomains, a Multi-Domain is probably the best choice for you. If you have a single primary domain, several subdomains, and will potentially diversify your site further in the future, a Wildcard SSL certificate is likely your best bet.

The following courses can help you to know more about SSLs and Cyber Security.


The ITIL® 4 Foundation Certification exam will give a basic knowledge of the ITIL concepts to the learners. The terminology which is to be used will be introduced. The structure of the course will be outlined in an effective manner as well. This will be an entry level exam which will help the learners to obtain a certain level of skills. It will be needed in order to work in the area of service management in organisations.

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The course is extensive and covers a range of key modules such as penetration testing essentials, open source intelligence methodology, social engineering penetration testing and network penetration testing methodology. Each module is discussed in-depth ensuring learners gain a firm understanding of the importance of applying skills learned in penetration testing methodology.

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This Certified Chief Information Security Officer programme is a first of its kind training. It is suited for top-level information security executives and any individual interested or aspiring to enter this field. The CCISCO focuses on technical knowledge and the application of information security management principles. The complete focus is on the point of view of an executive management.

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September 1, 2023

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