A wildcard certificate can simplify SSL management by securing an entire domain and its subdomains with a single certificate. However, when it comes to multiple level subdomains, understanding how wildcard certificates work, their limitations, and best practices is crucial.
This guide will explore everything you need to know about using wildcard certificates for multi level subdomains, helping you decide the best approach to enhance your website’s security.
Table of Contents
- What is a Wildcard Certificate?
- How Wildcard Certificates Work with Subdomains
- Wildcard Certificates and Second-Level Subdomains
- Multi-Domain Wildcard SSL Certificates
What is a Wildcard Certificate?
A wildcard certificate is an SSL (Secure Socket Layer) certificate used to secure a website and its subdomains with a single certificate. Unlike traditional SSL certificates, which protect a single domain or subdomain, a wildcard certificate uses an asterisk (*) to cover all subdomains under a specific domain. For example, a wildcard certificate for *.example.com would secure www.example.com, blog.example.com, shop.example.com, and any other subdomains at that level.
The wildcard feature makes it easier for website administrators to manage SSL for multiple subdomains, reducing cost and administrative efforts since only one certificate needs to be issued and renewed.
How Wildcard Certificates Work with Subdomains
A subdomain is a prefix added to a domain name to organize and navigate different sections of a website. For instance, in blog.example.com, “blog” is the subdomain, while “example.com” is the primary domain.
There are single-level and multiple-level subdomains:
- Single-Level Subdomains: These are subdomains directly under the main domain, like shop.example.com.
- Multiple-Level Subdomains: These include additional subdomain levels, such as secure.shop.example.com or blog.us.example.com. Multiple-level subdomains add another layer of specificity and are often used in larger organizations or websites with complex structures.
Wildcard certificates are generally designed to cover only single-level subdomains. For example, a certificate for *.example.com can secure any first-level subdomains like blog.example.com or shop.example.com but will not cover sub.sub.example.com by default.
For websites with complex domain structures, such as regional subdomains (us.blog.example.com), or those needing higher security levels, a different SSL strategy may be required. This might include using a combination of wildcard and SAN (Subject Alternative Name) certificates or managing multiple wildcard certificates for different levels. Proper planning ensures that all levels of a website’s structure are adequately secured, which is essential for maintaining user trust and data security.
Wildcard Certificates and Second-Level Subdomains
To create a wildcard certificate that covers second-level subdomains, you must generate a Certificate Signing Request (CSR) with the format *.blog.yourdomain.com. Here, the wildcard (*) substitutes for all potential second-level subdomains under the “blog” subdomain, such as secure.blog.yourdomain.com or media.blog.yourdomain.com. This approach is useful when you want to create subdivisions within a specific first-level subdomain.
However, if you want to add a second-level subdomain to another subdomain, like news.yourdomain.com, you will need a separate wildcard certificate for that subdomain.
Unfortunately, you cannot encrypt the subdomains of both blog.yourdomain.com and news.yourdomain.com with a single wildcard SSL certificate. Certificate Authorities (CAs) issue SSL certificates with only one wildcard (*). You can’t generate a CSR that looks like *.*.yourdomain.com to cover more than one second-level subdomain group. The wildcard (*) only applies to one specific field in the domain name submitted to the CA.
This limitation is primarily for security reasons. CAs need to verify every SSL application thoroughly, and allowing multiple-level subdomains under a single certificate would introduce too many variables, complicating the verification process and potentially compromising security.
For those needing to secure multiple second-level subdomains across different first-level subdomains, Multi-Domain Wildcard SSL certificates offer an effective solution. These certificates allow multiple wildcards across different domain levels to be secured under a single SSL certificate, providing flexibility and enhanced security for complex domain structures.
Multi-Domain Wildcard SSL Certificates: The Ultimate Solution for Multi-Level Subdomains
A Multi-Domain Wildcard SSL certificate is an efficient and cost-effective option when you need to secure multiple websites and subdomains across different levels. Unlike standard SSL or regular wildcard certificates, a multi-domain wildcard SSL certificate allows you to secure several domains and their subdomains—at various levels—with a single certificate. This type of certificate comes with an unlimited server license, meaning it can be used across websites hosted on the same server, different servers, or even multiple servers.
Why Choose Multi-Domain Wildcard SSL Certificates?
Imagine you need to secure the following 8 subdomains:
- yourdomain.com
- blog.yourdomain.com
- news.yourdomain.com
- dev.yourdomain.com
- dev.blog.yourdomain.com
- dev.news.yourdomain.com
- abc.news,yourdomain.com
- xyz.news.yourdomain.com
With a standard single-domain SSL certificate, you would need 8 separate SSL certificates, resulting in high costs and a cumbersome management process.
Using a Wildcard SSL certificate would reduce the number of certificates required to just four:
- *.yourdomain.com
- *.blog.yourdomain.com
- *.news.yourdomain.com
- *.dev.yourdomain.com
While this approach is more cost-effective than individual certificates, it still requires multiple certificates and involves additional costs and time for installation and renewal.
The Advantages of Multi-Domain Wildcard SSL Certificates
A Multi-Domain Wildcard SSL certificate simplifies this even further by allowing multiple domains and subdomains to be covered under a single certificate. Typically, these certificates come with 3 SANs (Subject Alternative Names) by default and can support up to 250 SANs for an additional fee. This flexibility means you can secure all necessary subdomains with just one certificate.
For the example above, you would need just one Multi-Domain Wildcard SSL certificate with an additional SAN:
- One multi-domain wildcard certificate to cover *.yourdomain.com, *.blog.yourdomain.com, *.news.yourdomain.com, and *.dev.yourdomain.com
By using a Multi-Domain Wildcard SSL certificate, you consolidate all your security needs into a single certificate. This reduces costs, minimizes administrative overhead, and simplifies SSL management, making it the best solution for securing complex domain and subdomain structures.
Bottom Line
You can’t encrypt second-level subdomains with a single Wildcard SSL certificate. If your website structure includes multiple levels of subdomains, a Multi-Domain Wildcard SSL certificate is the ideal solution.
Instead of purchasing separate wildcard certificates for each second-level subdomain, you can save both time and money by securing all your domains and subdomains with one multi-domain wildcard certificate. This approach simplifies the initial installation and streamlines renewals.
As the Internet continues to evolve and the need to secure complex domain structures grows, multi-domain wildcard certificates are becoming an increasingly popular choice for comprehensive and cost-effective security.
Save 10% on SSL Certificates when ordering today!
Fast issuance, strong encryption, 99.99% browser trust, dedicated support, and 25-day money-back guarantee. Coupon code: SAVE10
