A certificate includes a subject (e.g. www.innovaphone.com) which may be validated by the receiving client against the resource name used for the request to the server that delivers the certificate (e.g. http://www.innovaphone.com).

When a server provides multiple services however (e.g. www.innovaphone.com and wiki.innovaphone.com), it may be useful for the server to provide a wildcard in the certificate's subject (e.g. *.innovaphone.com which would match both service names). Such certificate is known as wildcard certificate.

See also SAN.

->  Wildcard certificate