Oracle eMail Server Administrator's Guide Release 5.2 A86653-01 |
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To exchange multimedia messages with MIME-compliant systems, you can configure your gateway to make sure messages and attachments are mapped to the correct types. In addition, if you will be exchanging messages and message attachments with a non-MIME-compliant system, you can set up a gateway that performs special encoding and decoding.
In most cases, the default MIME configuration will be sufficient for your needs. If you need to customize your MIME configuration, use the following tasks discussed in this chapter:
eMail Server uses information about attachment types to start the program that created the file when the user downloads the attachment. eMail Server provides some predefined attachment types. In addition, you can define new attachment types. When you add an attachment type, you must first add a generic type, then an attachment type of the same name that is platform-specific.
This task can be performed through either the Administration Tool GUI, or the OOMGR command-line interface.
"Parameters for Creating an Attachment Type" for more information about the parameters in this dialog box
See Also:
IOFCMGR>insert attachtype 2>name=<attachment_name
> 3>type=<attachment_type
> 4>platform=<user_platform
> 5>binary=[Y | N] 6>description="<description
>" 7>command="<launch_command
>";
See Also:
"Parameters for Creating an Attachment Type" for more information about the parameters available with this command |
The MIME standard has established conventions and names for many common attachment types, such as GIFs, PostScript documents, or formatted spreadsheets. When you install eMail Server, many of these standard MIME types are automatically mapped to their corresponding types in eMail Server so that the attachment types can pass through the SMTP/MIME gateway immediately. You can change these existing MIME-type mappings or create new ones.
Before creating a MIME attachment type, review the default attachment types to be sure one does not exist.
This task can be performed through either the Administration Tool GUI, or the OOMGR command-line interface.
"Parameters for Creating an Attachment Type" for more information about the parameters in this dialog box
See Also:
IOFCMGR>insert attachmap gateway=<gateway_type
> 2>foreigntype=<foreign_attachment
> 3>localtype=<defined_type
> 4>description='<description
>';
The following table lists the standard MIME attachment types that are automatically mapped to eMail Server attachment types during installation. Some of these types may only be available on certain platforms.
You can update a MIME attachment map if any of the information, such as the gateway type or foreign attachment type, changes.
This task can be only be performed through the OOMGR command-line interface.
IOFCMGR>update attachmap gateway=<gateway_type
> 2>foreigntype=<foreign_attachment
> 3>localtype=<defined_type
> 4>description='<description
>';
Some MIME attachment types may not have corresponding eMail Server attachment types. In this case, you can use a converter to map a MIME attachment type to an eMail Server attachment type. A converter is a program that converts and maps a MIME attachment type to an eMail Server attachment type, and vice versa.
If you can map a MIME attachment type either with or without a converter, then you should select the method that does not use a converter.
For example, eMail Server attachment type 67 (XBM) maps to MIME types image/x-xbitmap and image/x-xbm. If the mapping for eMail Server attachment type XBM to MIME type image/x-xbm is created first (on the DCN), an attachment of type XBM will be transmitted as an image/x-xbm MIME part with no type conversion.
A format converter should perform bidirectional data conversion. In other words, if you select a specific converter to map a MIME type to an eMail Server type, use the same converter to map the eMail Server type to the MIME type.
Converter programs cannot be used for multipart/<multipart-subtype> MIME types. The gateway ignores these attachment type mappings.
If you use an external converter, it must:
In addition, the following must hold true:
To define the full pathname to the format converter, use the Converter parameter. If a relative pathname is specified, then the gateway assumes the path is relative to $ORACLE_HOME/bin.
To configure the external attachment format converters, use the insert attachmap
command.
The following is an example using a converter for inbound messages. The example defines a mapping between MIME-type application/mac-binhex40 and eMail Server type 7. When the gateway receives an application/mac-binhex40 body part in an inbound MIME message, it sends the data through the /oracle/bin/ofc_bh40.sh -D filter. The filter output is inserted into eMail Server as attachment of type 7.
IOFCMGR>insert attachmap gateway=smtp 2>foreigntype=application/mac-binhex40 localtype=7 3>converter=/oracle/bin/ofc_bh40.sh 4>description='converter for macbin <-> mac-binhex40';
When an external converter exits or terminates inbound messages with an error, the original MIME body part is inserted as the attachment type defined in the default_type
process parameter. Data that cannot be converted is prepared with an X-Orcl-Comments header, indicating that the gateway has failed to convert the data. The comment is followed by the original Content-type and Content-Transfer-Encoding headers and the data.
The following is an example using a converter for outbound messages. The example defines a mapping between MIME type application/x-uuencode and eMail Server type 1.
IOFCMGR>insert attachmap gateway=unix 2>foreigntype=application/x-uuencode localtype=1 3>converter=/oracle/bin/ofc_uu.sh 4>description='converter for uuencode/decode';
The gateway sends the contents of a type 1 attachment in an outbound message through the /oracle/bin/ofc_uu.sh -E filter. The filter output becomes the data of an application/x-uuencode MIME body part in the outbound message.
The SMTP/MIME gateway assumes the output of an external type converter is 7-bit ASCII, which does not require further transfer encoding. In the outbound MIME message, the 7-bit content transfer encoding is used.
When an attachment type conversion program fails, the attachment is sent as an application/octet-stream MIME part, and the base64 content transfer encoding is used.
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