SSL Certificate Subject Alternative Names (SANs)

Subject Alternative Names or SANs allow you to secure multiple domains from one SAN SSL certificate. SANs are additional domain names added to an SSL certificate.

SANs are the ideal solution to secure Microsoft Exchange and Office Communications Servers with Unified Communications Certificate (UCC), also known as a SAN cert.

For example, an SSL certificate’s main domain could be with three included SANs of,, and Then, when any of those four domains are requested over HTTPS in a browser, the end-user won't get any browser certificate-mismatch errors.

browser certificate viewer

SANs are also very useful as a to fix the www versus no-www problem. If you are issued an SSL certificate for it will only work properly for exactly and not just (without the www). Adding a SAN value of ‘’ to the cert fixes this problem. The converse of this works too, that is you can add a SAN value of for certs issued just (without the www).

SAN certs come in two validation types: domain validated (DV) and organization validated (OV). 

DV SAN certs will only support SANs that are subdomains of the base domain in the cert whereas OV SAN certs will allow you to include any Fully-Qualified-Domain-Name (FQDN) that you own (internal .local, server names and private IPs as SANs have been discontinued industry-wide).

Learn more about the SAN certs that we have to offer.

Please contact our support team if you have any additional problems or questions.

Mar 7, 2018