Use Subject Alternative Names (SANs) to Secure Your Entire Environment
Unified Communications (UC) certificates (also called SAN certificates) use Subject Alternative Names to secure up to 25 domains, sites, and subdomains with one certificate. Four domains are included in the base price of the UC certificate, but additional names can be purchased.
For example, with a UC certificate you can secure
www.example.com
www.example2.com
www.example3.net
mail.example.net
dev.example2.com
This makes UC certificates perfect for Exchange/OCS environments or any environment where you need to secure multiple names across different domains.