A Complete Guide on Multi-Domain SSL Certificates

SSL/TLS certificates are becoming popular for website owners because they offer strong security through robust encryption.

When a website has these certificates, you’ll see trust indicators like “https” and a padlock in the address bar.

These signals reassure customers that the site is secure. SSL certificates come in different types, each securing the web in different ways.

Users use a Standard SSL certificate for securing a single domain and sub-domain whereas they use a Wildcard SSL certificate for securing varied first-level subdomains and the primary domain.

But what if you have varied businesses and hence have varied domains? 

How do secure varied domains and multiple-level subdomains?

A Complete Guide on Multi-Domain SSL Certificates

Answer – A Multi-domain SSL Certificate.

What is a Multi-domain SSL certificate?

A Multi-domain SSL certificate (also named UCC (Unified Communications Certificate) or SAN (Subject Alternate Name) SSL) is the most versatile SSL certificate that secures multiple domains (fully qualified domain names) and varied sub-domains of all levels with a single certificate. 

Organizations are plunging into multiple ventures and are displaying and promoting their products/services on online platforms. This calls for SSL certificate security for securing website and customer data. Purchasing varied SSL certificates is an expensive deal and managing them is a tough call.

A multi-domain SSL certificate is a budget-friendly SSL certificate that manages and secures varied websites. The site owner can add or delete domains from this certificate easily, and hence it proves to be a hassle-free digital security solution.

The main motto of this certificate is to provide maximum security at a minimum cost.

One single multi-domain SSL certificate can secure up to 250 domains, which makes it an ideal security solution.

All additional domains can be purchased as SANs because this certificate will permit you to secure two to three domains. All the other domains that need to be secured must be mentioned as additional SANs while filling in the certificate details.

Thus, SANs enhance the security functions of this SSL Certificate, since it enables encryption security for multiple domains. 

Types of Domains You Can Secure with Multi-Domain SAN SSL Certificates:

As stated above, these SSL certificates secure up to 250 domains depending on the Certificate Authority (CA) issuing them. The sole rule to obtain this certificate is that all the domains should be under the same company’s name. 


  • www.domain.com
  • www.domain.co.uk
  • www.example.com
  • blog.example.com

The above example shows domains and subdomains, wherein blog.example.com is a subdomain of www.example.com. You need to place it as an additional SAN to secure it under the main multi-domain SSL certificate.

Benefits of Multi-domain SSL Certificate:

Multiple benefits of a Multi-domain SSL certificate make it more desirable and demandable. 

  • Cost Effective:

Web owners do not need to purchase many standard SSL certificates to secure each domain because only one multi-domain SSL certificate will secure their whole web. New domains can be added by re-issuing the SSL certificate. Hence, this SSL certificate proves to be a cost-effective digital security solution.

  • Unlimited Re-issuances:

Since re-issuances are unlimited, the owner can easily add new domains by reissuing the certificate. The re-issuance of this certificate is essential if the business owner wishes to operate the domain from a new server, or in case of a missing (lost) private key, etc. 

Generate the CSR, validate the domain name, and complete the issuance process. 

  • Strong Encryption:

256-bit Key encryption and 2048-bit RSA encryption will secure client-server communications and keep them safe from prying eyes.

Hackers will find it tough to break this security barrier and thus customer/site data will stay secure.

  • Trust Seal:

These certificates offer a site seal, which is placed on the site. The site seal is both static (portraying a secured site) and dynamic (portraying the authenticity of the company). This ensures the customers about the authenticity of the site. 

  • Browser Compatibility:

These SSL certificates are compatible with popular browsers and hence SSL warnings are eliminated. In cases of non-compatibility, the browser is bound to display an SSL error and refrain the user from using the site.

  • Availability in All Validations:

Unlike Wildcard SSL certificates, which are not available in EV validations, a multi-domain SSL certificate is available in all validations. The business owner can select the certificate brand and the validation type as per their business requirements and approach the CA for the same.

Since EV SSL is also available with a multi-domain SSL certificate, a dual security solution is established. Multiple domain security with the highest level of authentication and verification of the legitimacy of the company assures the users about the security of the organization and its site.

How to Get a Multi-domain SSL Certificate?

The purchase process of a Multi-domain SSL certificate is like that of a standard SSL certificate. Simply state the number of additional domains that need to be secured with the primary domain. These additional domains are termed as ‘SANs.’ 

Mention the count of SANs you require and add a few more for the future before completing the purchase process.

In case you wish to add or modify the SANs, you need to reissue the certificate. 

The purchase process also depends on the type of validation since these certificates are available in all the validations, i.e., DV (Domain Validation), OV (Organisation Validation), and EV (Extended Validation).

  • Process for DV Multi-domain SSL Certificate:

Generate the CSR (Certificate Signing Request) for the SSL certificate and submit your details. If your CSR is error-free, you will receive your SSL certificate within minutes since no other paperwork is needed. 

Confirm the domain ownership via the verification link sent by the CA to your registered email address and get your certificate.

Tip: Comodo Positive SSL Multi-domain certificate is a DV SSL certificate that is cheap and can be issued quickly.

  • Process for OV Multi-domain SSL Certificate:

Confirm the legitimacy of your business by submitting the company’s documents (legit address, contact details, telephone number, etc.) as required by the CA. The CA will verify these details and on positive verification will issue the SSL certificate.

  • Process for EV Multi-domain SSL Certificate:

An EV Multi-domain SSL certificate is eligible only if your organization has been operating for 3 or more years. Submission of all the documents required for verifying OV SSL, plus a few more document additions regarding the existence and operational functionality of the business need to be submitted to the CA for obtaining this SSL certificate.

On positive verification of these documents as per the CA/B Forum, the CA will complete other verification procedures and later issue the certificate.

Tip: Comodo EV Multi-domain SSL certificate comes with a huge warranty and ensures complete authentication of business.

Compatibility Between Multi-Domain SAN SSL Certificate and Browsers:

In the case of a Multi-domain SSL Certificate, all the domains and sub-domains must be mentioned in the SAN (Subject Alternative Name) field. In the absence of a domain name missing under the SAN field, the visitor/user will be refrained from accessing that website. 

Note: After all your domain names are listed in the SAN field, the client will check the SSL certificate as well as the SAN list. If all the details match each other a secure https connection will be established on the website. 

The Cutting-Edge Multi-Domain SSL Features:

Multi-domain SSL certificate is loaded with ample features which makes this certificate worth its price.

  • A Single Certificate secures up to 250 Domains.
  • Provides 256-bit Robust Encryption Security
  • Key Length 2048 bits
  • Available in all Validations
  • Unlimited Server Licenses and SSL Re-issuances
  • Huge Warranty  
  • 99.9% Mobile-Browser Compatibility
  • Trust Icons Visible on all listed Domains/Subdomains
  • Supports all the Servers

Wrapping Up:

Large corporates and web owners with huge and multiple businesses love to use multi-domain SSL certificates since one single certificate can secure multiple sites and servers. 

This budget-friendly certificate works on varied servers and is loaded with ample benefits. 

Money-back offers and trust seals make this SSL certificate one of the best security solutions in today’s digital world.

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