Multi-Domain also referred commonly as SAN Certificates, utilize Subject Alternative Names (SANs) are also known as Unified Communication Certificates (UCC) to secure up to 250 different domain names, subdomains, and public IP addresses, using only one SSL Certificate and requiring only one IP to host the Certificate.
SAN SSL are completely compatible with Microsoft Office Communications Server and Microsoft Exchange products. You can secure different common names or domain names with just one certificate, it works with both internal network name and external domain names.
