Supported routing, format, and access protocols

The IBM® Domino® server and IBM Notes® client support both Internet standards and Notes protocols for message routing, retrieval, and formatting. On the server, the Domino mail router (the router) can send and receive messages using the Simple Mail Transfer Protocol (SMTP) and Notes Remote Procedure Calls (NRPC), or Notes routing. To enable users to retrieve mail, the server supports the Internet access protocols, IMAP and POP3, as well as NRPC.

The Domino HTTP service interacts with Domino mail databases to provide mail service for HTTP clients, such as the IBM iNotes® client.

Domino sends and stores messages in both MIME format and Notes rich text format, and the Notes client creates and sends messages in either format.

Mail clients retrieve messages from the server using NRPC, IMAP and POP3. In addition, Web clients, such as the iNotes client, access mail through the Domino HTTP service. The Notes client sends and retrieves mail using NRPC, or Internet protocols (SMTP, IMAP and POP3).

Mail routing protocols

When a new message arrives in, the router determines where and how to send the message. By default, the router uses Notes routing to transfer mail from one server to another. If the server has both SMTP and Notes routing enabled for the local Internet domains, the router chooses the optimal protocol to use to move the message to its destination. The protocol selection is based on the current message format, the Domino version of the server that holds the recipient's mail file, and the format preference specified in the recipient's Person document. For example, the router uses SMTP to route the MIME copy of a message to a POP3 recipient's server, and uses Notes protocols to route the Notes rich text format copy of a message to a Notes recipient's server.

You can also configure Domino to use SMTP to route mail. SMTP routing can be used instead of, or in addition to, Notes routing. You can configure a Domino server to use SMTP when transferring mail to destinations within the local Domino domain only, to external Internet domains, or both.

Supported message formats

Domino transports and stores messages in both MIME format and Notes rich text format. The transit format of a message depends in part on the routing protocol used, and can differ from the format in which the message is stored in the destination mail file. When transferring messages over Notes routing the router handles messages in either MIME or Notes format. Messages sent over SMTP are always sent in MIME format.

The format used to store a message depends on the storage preference specified in the user's Person document. A mail file can store messages in MIME format only, Notes rich text format only, or in both formats, accepting messages as is, regardless of format. Administrators should ensure that each user's Person document specifies the format preference appropriate to their mail client. For example, because IMAP clients require messages in MIME format, the Person document of a user who always accesses mail from an IMAP client should specify MIME as the format preference for incoming mail.

To ensure that users receive messages in the format best suited to their chosen mail clients, Domino converts messages between formats as needed. The Router may convert a message during transfer between servers or when delivering the message to a user's mail file. Conversion during transfer occurs when a message in Notes format must be sent over SMTP, or when routing a MIME message to a Notes user that is set to Notes Rich Text in their Person document. For example, The Domino IMAP and POP3 services also convert messages, as when an IMAP or POP3 client needs to retrieve a message stored in Notes format.

Because Notes routing can transport messages in MIME format, on networks that support both Notes routing and SMTP, a MIME message may travel over both protocols enroute to its destination.

POP3 and IMAP clients, which always send messages to the server over SMTP, create messages in MIME format. The Notes client creates messages in either Notes rich text or MIME format, depending on the format required by the intended recipient. When a user sends a message from a Notes client to another Domino mail user, the client software looks up the format preference specified in the recipient's Person document to determine which format to send. If the Person document indicates that the user's mail file stores messages in MIME format (as when a user accesses mail from an Internet mail client, such as an IMAP client), the sender's Notes client software sends messages to that recipient in MIME format.

If a recipient is not listed in the Domino Directory, the client software sends the message in the format that corresponds to the address type; sending recipients with Internet-style addresses, such as, messages in MIME format; and recipients with Notes-style addresses (Jane Doe/Sales/Renovations@Renovations), Notes rich text.

When sending messages to multiple recipients, the client software creates the message in both MIME and Notes rich text formats if necessary. For example, the client software creates a Notes rich text format message for a recipient who uses a Release 4 Notes client and creates a MIME message for a recipient who uses a POP3 client.

By combining SMTP, Notes routing, and automatic message conversion, Domino provides flexibility in setting up your mail infrastructure. For example, you can set up a mail system that is based completely on Internet standards and use the router to route MIME messages over SMTP. You can set up a mail system that is based completely on Notes mail and use the router to route Notes format messages over Notes routing. Or you can set up a mail system that uses both SMTP and Notes routing, sends both MIME and Notes format messages, and uses automatic message conversion to ensure that clients receive mail in the proper format.

Mail access protocols

Domino supports Internet mail access protocols such as IMAP and POP3 and also offers mail access to Notes clients. IMAP and POP3 clients connect to their respective protocol services to retrieve and send mail by way of an SMTP server. The Notes client can use Notes protocols to connect to a Domino mail server to read and send mail, and can also use IMAP or POP3 to access mail on a Domino server or on non-Domino mail servers -- for example, a UNIX™ sendmail server.