Subject Alternative Name

An example of a Subject Alternative Name section for domain names owned by the Wikimedia Foundation

Subject Alternative Name (SAN) is an extension to X.509 that allows various values to be associated with a security certificate using a subjectAltName field. These values are called Subject Alternative Names (SANs). Names include:

• Email addresses
• IP addresses
• URIs
• DNS names: this is usually also provided as the Common Name RDN within the Subject field of the main certificate.
• Directory names: alternative Distinguished Names to that given in the Subject.
• Other names, given as a General Name or Universal Principal Name: a registered object identifier followed by a value.

See also

• Wildcard certificate