What Are SSL Certificates for Subdomains and How to Use Them

Everything you ever wanted to know about Wildcard SSL certificates (SSL certificate for subdomain).

Secure Sockets Layer (SSL) Certificates are crucial for all websites now, both from a security and a visibility standpoint. SSL Certificates serve as cryptographic measures to secure the data being transmitted over a computer network, between a client and server.

And as of last July, Google has also made it mandatory for all websites to carry an SSL certificate. Sites without SSL certificates are flagged as ‘Not Secure’, which can drastically hurt their traffic and prevent them from rising high in Google search results.

You can secure your website if your primary domain and all your subdomains are secured. If your subdomains are not secured with SSL certificate then you might fall a victim of man in the middle attack.

Generally speaking, a standard SSL certificate only allows you to secure a single domain. Though you can use standard certificates to encrypt each sub-domain individually, that could be cost prohibitive.

That doesn’t help you much if your website uses multiple sub-domains, you still need an SSL certificate for all of them, but hopefully not at that price.

In this article, we’ll show you how to use an SSL certificate for all subdomains.

An SSL Certificate for All Subdomains — the Wildcard SSL Certificate

If you want to secure all your subdomains with a single certificate, you need to purchase a Wildcard SSL certificate. This is an SSL certificate made for securing all of a website’s subdomains.

For example, if you are running a domain called website.com, a Wildcard SSL certificate will allow you to also secure its subdomains such as blog.website.com or shop.website.com.

Anyone who has multiple subdomains within their primary domain structure should consider getting a Wildcard SSL certificate for all of their subdomains. This can make everything extremely convenient and it’s also a lot more reasonable overall than securing all your subdomains with individual certificates.

Wildcard SSL Certificates are currently available in two assurance levels — Domain Validated (DV) Certificate and Organization Validated (OV) Certificate. Unfortunately, Wildcard SSL Certificates are not available as Extended Validation (EV) Certificates, owing to their open-ended nature. As such, you cannot receive the green address bar and padlock if you use wildcard SSL certificates.

You can purchase Wildcard SSL certificates for periods of one or two years. Once the period is about to expire, you’ll have to get the certificate renewed.

How do I use an SSL Certificate to encrypt all Subdomains?

After you purchase a Wildcard Certificate, you have to generate a Certificate Signing Request (CSR) for wildcard SSL. To do so, you must fill up a form and enter your Fully Qualified Domain Name.

The Fully Qualified Domain Name comprises three parts.

• Top-Level Domain: This is the .com or .org at the end of the website address.
• Second-Level Domain: This is the name of the website in the center. For example, in www.website.com, the Second-Level Domain is the “website”.
• Subdomain: This is the first part of the address, the part that’s usually denoted as “www”.

In order to get an SSL certificate for subdomains, you’ll have to enter an asterisk in place of the subdomain. For example, if you want to secure all the subdomains under website.com, you’ll have to enter *.website.com.

The asterisk placed at the subdomain level allows the Wildcard SSL certificate to secure all the subdomains within that primary domain. It can even secure new sub-domains that you hadn’t even added at the time you got the certificate, making them essentially future-proof.

Benefits of Using Wildcard SSL Certificates for Subdomains

Here are the primary benefits of using the Wildcard SSL Certificate for all Subdomains:

• You can secure an unlimited number of subdomains within the primary domain.
• You can manage all your subdomains with a single certificate instead of having to handle several different certificates.
• Getting a single Wildcard SSL certificate is a lot cheaper than getting multiple standard SSL certificates for each individual subdomain.
• The Domain Validated Certificate can be issued within a few minutes.