You can control how a Domino 6 server transfers a MIME message to a Domino 4.6 server if it cannot access a user's Person document. The following table describes the formatting options for incoming mail in the Person document.

Format preferences for incoming mail	Description
Prefers Notes Rich Text	The Domino server converts the MIME message to Notes format and transfers it, reducing storage space and bandwidth use but with some loss of message fidelity.
Prefers MIME	The Domino server converts the MIME message to Notes format and also creates an attachment containing the original MIME, preserving message fidelity but increasing storage space and bandwidth use.
Keep in Sender's format	The Domino server converts MIME messages to Notes format without an attachment. This is the default setting.

If you select to convert the message to Notes format and also create an attachment containing the original MIME, Lotus Domino 6 preserves full message format. If an Internet mail client accesses the message, Domino sends it the MIME from the attachment. The Domino 4.6 server deposits both the Notes format message and the MIME attachment in a user's mail file for this reason. For these messages in a mixed-release environment with this conversion setting, mail storage requirements and network utilization roughly double for each of these messages only.

Internet mail conversion in mixed-release environments

In a mixed-release environment, routing native MIME messages and sending Notes format messages to the Internet requires some conversion. Conversion takes place in the following scenarios.

Using the inbound and outbound services of the Domino 4.6 SMTP/MIME MTA

The MTA converts outbound Notes messages to MIME format and routes them via SMTP. It converts inbound MIME messages to Notes format (with or without a MIME attachment) and routes them over Notes RPC using the Notes router. The Domino 4.6 MTA converts and delivers messages based on the settings in the recipient's Person document, if the MTA can access it. If the setting of the Internet Message Storage field in the Notes 4.6 Person document is:

• Prefers Notes Rich Text (Notes only in Lotus Notes/Domino 4.6), the MTA converts the message to Notes format and routes it.
• Prefers MIME (Internet only in Lotus Notes/Domino 4.6), the MTA packages the messages as a MIME attachment and routes it.
• No Preference (Notes and Internet in Lotus Notes/Domino 4.6), the MTA converts the message to Notes format, adds an attachment containing the original MIME, and routes it.

The router checks the recipient's Person document in the Domino Directory. The field "Format preference for incoming mail" determines the recipient's preference for Internet messages. If the message is in Notes format and

• The field is set to Prefers Notes Rich Text, the router delivers the message and stores it in Notes format (CD format).
• The field is set to Prefers MIME, the router converts the message to Native MIME format and delivers the MIME message.
• The field is set to Keep the Sender's format, the router delivers the message and stores it in Notes format (CD format).

If the message is in MIME format and

• The field is set to Prefer Notes Rich Text, the router converts the message to Notes format and delivers the Notes format message.

  Note If the NOTES.INI parameter MailDeliverCDorMime is set to 1 on the server, the router does not convert the message and instead delivers it in MIME.

• The field is set to Prefer MIME, the router delivers the message and stores it in Native MIME format.
• The field is set to Keep in Sender's format, the router delivers the message.

Note Inbound Internet mail is stored in Native MIME format for recipients whose format preference for incoming mail is set to "Prefers MIME" or "Keep in Sender's format." If transferring to a Domino 4.6 server, the MIME message is converted to Notes format because the Notes 4.6 client cannot understand Native MIME.

When a Domino 6 server transfers a message to a Domino 4.6 server

If the message is in Notes format, the router simply transfers the message to the Domino 4.6 server.

If the message is MIME, the router tries to access the recipient's Person document. If it has access to the recipient's Person document, it checks the Internet Message Storage field (Domino 4.6) or Format preference for incoming mail field (Domino 6).

When a Native MIME message passes from Lotus Domino 5 or later to a Domino 4.6 server, Lotus Domino 5 or later converts the Native MIME message to Notes format (CD ) or CD plus the MIME stream as an attachment. If the message is delivered to a Domino 4.6 server, the CD format is required because Notes 4.6 clients cannot understand MIME. The attachment is required to maintain fidelity for IMAP and POP3 clients, for final delivery to Lotus Domino 5 or later, and for retention of content if the message is encrypted with S/MIME.

• If the field is set to Notes only (Domino 4.6) or Prefers Notes Rich Text (Domino 6), the router converts the message to Notes format and transfers the Notes format message.
• If the field is set to Internet only (Domino 4.6) or Prefers MIME (Domino 5 or later), the router converts the MIME message to a MIME attachment and transfers the MIME attachment as the message.
• If the field is set to Notes and Internet (Domino 4.6) or No Preference (Domino 5 or later), the router converts the message to Notes format, adds an attachment containing the original MIME, and transfers the Notes format message with the MIME attachment.

If the message is encrypted (S/MIME format), the router creates an attachment containing the S/MIME and creates a Notes format message explaining that the message is encrypted and cannot be converted to Notes format.

If the router cannot access the recipient's Person document -- for example, if the recipient is in another domain and the router cannot access that domain's Domino Directory -- the router converts MIME messages to Notes format and transfers them. You can control this conversion by setting the router to either follow the default behavior or to also add an attachment containing the original MIME to the Notes format message. The default behavior conserves disk space and bandwidth but reduces message fidelity; the optional behavior preserves message fidelity, but consumes additional disk space and bandwidth.

When a Domino 6 router sends mail over SMTP

If a Domino 6 router must send a message in Notes format over SMTP, it converts the message to MIME.

Note The Domino 4.6 SMTP/MIME MTA supported encapsulation, which placed Notes-specific information in an attachment that could be converted back into Notes data by another MTA. The Domino 6 router does not support Domino 4.6 encapsulation, but maintains Notes data by another method so that another Domino 6 router can convert the information back into Notes data.

When a Domino 6 server replicates with a Domino 4.6 server

When a Domino 6 server replicates a database with MIME content to a Domino 4.6 server -- for example, if a mail file is on both a Domino 6 and a Domino 4.6 server, with MIME messages in the database on the Domino 6 server -- Domino converts any MIME to Notes format.

Using IMAP and POP3 clients to retrieve messages

If a message is stored in Notes format and retrieved by an Internet client, the IMAP and POP protocols convert the Notes format message to Native MIME for the IMAP and POP3 clients.

See Also

Domino mail messaging changes since Lotus Domino 4.6
Specifying inbound and outbound MIME conversion options