What Is a Wildcard SSL Certificate?

Secure all of your first-level subdomains with a time- and money-saving digital certificate

Securing a website’s subdomains used to mean getting a separate SSL certificate for each one, but not anymore. If you’re asking, “What is a Wildcard SSL Certificate?” The answer is that it’s the savvy solution that lets you secure all your subdomains with just one certificate.

Although it’s not a new technology, its ability to streamline website security efficiently deserves attention. Let’s look at how wildcard SSL certificates work and their ongoing relevance in web security.

What Is a Wildcard SSL Certificate?

A wildcard SSL/TLS certificate is a small digital file that allows you to secure a domain and its subdomains. Unlike a basic SSL/TLS certificate, a wildcard certificate features a nifty asterisk (*) in its domain name slot. This feature lets you cover not just one but unlimited single-level subdomains under a single overarching domain.

Here’s a quick peek at what it looks like:

For website admins, its versatility streamlines the certificate lifecycle management process. Get a certificate for *.mydomain.com, and you’re all set to secure www.mydomain.com, mail.mydomain.com, store.mydomain.com, and any other first-level subdomain you might dream up.

How Does a Wildcard SSL Certificate Work?

Once set up, the wildcard SSL certificate is tied to your primary domain, using the asterisk (*) symbol to stand in for any possible subdomains. 

This special asterisk in your website’s Common Name (CN) field is the key to its versatility. This is what enables it to secure countless single-level subdomains connected to your main website. The moment someone visits any of these subdomains, the certificate steps up, confirming its validity and kicking off a secure, encrypted session. 

This means you don’t have to juggle separate certificates for each subdomain, making your life easier and extending the credibility of your entire online presence with just one certificate.

Why Should I Consider Getting a Wildcard SSL Certificate?

Well, if you’re looking for a solution to secure countless resources across your domain, a wildcard SSL certificate is the solution you need. With just one wildcard SSL certificate, you can secure your main site and an unlimited number of first-level subdomains. Whether it’s your main site, a customer portal, an online store, or an email platform, they’re all covered under this umbrella.

So, why go for a Wildcard SSL certificate? 

• It’s a time-saver: You can avoid the hassle of managing multiple certificates for each subdomain. No more jumping through hoops for each subdomain.
• It’s kind to your budget: Investing in a wildcard certificate is an economical choice because you’re investing in a single asset that covers a lot of ground.
• Securing your subdomains is a trust booster: Users feel more comfortable and confident on a secure website that uses encryption to protect their data.

What Does a User See When You Install a Wildcard SSL Certificate?

The above is a stellar example of securing a main domain along with its subdomains under a single certificate. Commonly, SSL certificates cover both the www and non-www versions of a domain — think www.google.com and google.com. However, a wildcard SSL certificate steps up the game by extending protection to an array of subdomains under Google, like adwords.google.com, earth.google.com, and mail.google.com, among others.

How Many Subdomains Can a Wildcard SSL Certificate Secure?

The sky’s the limit. A wildcard SSL certificate allows you to encrypt your main domain and virtually unlimited first-level subdomains.

For example, if your domain is mydomain.com, a wildcard SSL certificate can secure any number of subdomains, like mail.mydomain.com, specified as *.mydomain.com. However, keep in mind that this type of certificate does not cover second-level subdomains like login.mail.mydomain.com.

When You Should Use a Multi-Domain Wildcard Instead

If you need to secure multiple domains alongside multiple levels of subdomains, you may want to consider a specialized solution like a multi-domain wildcard SSL certificate. This type of SSL/TLS certificate offers more extensive coverage. It’s perfect when your setup requires securing various domain names and their multiple subdomains with a single certificate.

For example, with multi-domain wildcard certificate, you could secure www.mydomain1.com, its subdomain shop.mydomain1.com, and a separate domain, www.mydomain2.net, along with its subdomain blog.mydomain2.net, all under one certificate. This type of certificate is a versatile choice for complex or multi-domain environments.

A versatile SAN-supported wildard certificate, such as the Comodo Wildcard Multi-Domain SSL, enables you to:

• Add up to 1,000 domains
• Secure an unlimited number of subdomains across multiple domains, and
• Including both first-level subdomains like shop.mydomain1.com and second-level subdomains like mycart.shop.mydomain1.com.

This solution is ideal for organizations operating multiple domain names on a single server. It offers a cost-effective and straightforward approach to web security management.

Some Answers to Simple Wildcard SSL Queries

We hope that this article has answered your question, “what is a wildcard SSL certificate?”

If you’re inquiring about a wildcard SSL certificate and are considering buying one, it’s likely you have questions about IP sharing, server, and browser compatibilities. Here’s what you should know to prioritize website security and accessibility when making such an important decision.

Can a Wildcard SSL Certificate Share an IP Address for All Subdomains?

Yes, a wildcard SSL certificate allows all of your subdomains to share a single IP address, simplifying your SSL certificate management and reducing costs​​.

Is a Wildcard SSL Certificate Compatible with All Browsers?

Yes, wildcard SSL certificates are designed to be compatible across virtually all major browsers, ensuring a secure, encrypted connection for users no matter how they access your subdomains​​.

Are There Any Potential Incompatibilities with Wildcard SSL Certificates?

Wildcard SSL certificates are compatible with most modern servers, services, and devices. However, some specific server types may not support them. Although these issues are rare, always check with your provider to avoid any hiccups.

Need a Hand with Your Wildcard SSL Renewal? We’re Here to Help

Like any other digital certificate, a wildcard SSL certificate has an assigned shelf life. Certificate validity is a critical issue, and you have to closely monitor it to stay on top of your certificate lifecycle management to keep your site secure.

But before the clock runs out on your wildcard SSL certificate, it’s time to refresh it via renewal. Without a timely update, your site could start turning away visitors with a glaring security warning instead of welcoming them with open arms.

Is it renewal time for your wildcard SSL certificate? Let’s get you set up.

For Existing ComodoSSLStore Customers

If you’re ready to renew, simply log in to your ComodoSSLStore account and click the “Renew” button to issue your replacement wildcard certificate swiftly.

For New Customers

What if you’re new to Comodo SSL? Start by generating a Certificate Signing Request (CSR). For further assistance, our Comodo SSL support team is here to guide you through the process for a smooth and automated certificate management experience.