3) IMAP4 Agreement
The IMAP protocol is an abbreviation for Internet Message Access Protocol (Internet Messaging access Protocol) and is now commonly used in version 4, which provides users with a choice of the ability to receive mail from a mail server, server-based information processing, and shared mailbox capabilities. IMAP4 allows multiple segments of processing to be queried after the user logs on to the mail server. First, the user can read only the Mail letterhead (messageheader) in the e-mail message, and the user can then choose to download the specified mail or all of the messages. IMAP4 the message to the user at one end of the mail server.
4 HTTP protocol and HTML language
The HTTP protocol is the acronym for the Hypertext Transfer Protocol (Hyper text Transfer Protocol), a mail server that supports this protocol, and can provide e-mail services via the web.
5) MIME Protocol
MIME is an abbreviation for the Multipurpose Internet Mail Extensions (Multipurpose Internet Extensions) protocol. As an extension of the SMTP protocol, MIME sets the standard for transmitting non-text e-mail attachments through the SMTP protocol. At present, the use of MIME is already beyond the scope of sending and receiving e-mail, as one of the basic protocols for transmitting multimedia information over the Internet.
6) LDAP protocol
The LDAP protocol is an abbreviation for the Lightweight Directory Access Protocol (Lightweight Directory Access Protocol). By storing the relevant content in a unified directory, the directory service provides users with a means of querying information based on how the client/server works.
Three, multi-mail server support capabilities
Support for multiple mail servers has two meanings, is physically supporting multiple mail servers working together and logically supports multiple virtual mail servers, also known as multi-domain Mail services.
The physical support of multiple mail servers means that the product can build a multi-level messaging service in a complex network environment. For a large organization, in addition to having an enterprise-class mail server, each department is allowed to establish and manage departmental mail servers on its own. Enterprise-class mail servers are connected directly to the Internet, and internal to each department mail server, is the vertical Mail service node.
A multi-domain mail service is a single physical server that provides e-mail services to multiple organizations or departments that are independently registered for Internet domain names. In the eyes of the outside world, these institutions or departments seem to have their own dedicated mail server. Therefore, it is also known as a virtual mail server.
Iv. other service support capabilities
1) Mail paging service
The mail server providing this service can send the email to the addressee's pager according to the request of the sender, when receiving the e-mail message from the user.
2 Mail to Fax Service
Some mail servers also provide options, according to the request of the sender, the e-mail received by the mail sent to the recipient designated fax machine.
3 Mail User Group service
The Mail User group (mailinglist) service, also known as a mailing list, is a network service that communicates information about a topic through e-mail.
4) Network News Service
Network news is a user with common interests on the Internet, an invisible user exchange network composed of exchanging opinions.
5 Multilingual Services
Some mail servers also provide multilingual service support capabilities, allowing administrators and users to enter customized text information in multiple languages, and automatically select the appropriate language to provide services based on the user's country characteristics.