System 2.0.0.0 4.0.0.0 System.Enum The enumeration is used by the and classes to specify a level of access to an SMTP host computer. The class demands an when sending electronic mail to the SMTP host for delivery. Specifies the level of access allowed to a Simple Mail Transport Protocol (SMTP) server. Field 2.0.0.0 4.0.0.0 System.Net.Mail.SmtpAccess Connection to an SMTP host on the default port (port 25). Field 2.0.0.0 4.0.0.0 System.Net.Mail.SmtpAccess Connection to an SMTP host on any port. Field 2.0.0.0 4.0.0.0 System.Net.Mail.SmtpAccess No access to an SMTP host.