How to configure Internet e-mail message formats at the user and the domain levels in Exchange Server 2003

For a Exchange 2000 Server version of this article, see 319252 .


This step-by-step article describes how to configure Internet e-mail messaging formats at both the user and the organizational level. For most organizations, e-mail messaging has become an increasingly important mode of communication. However, not all organizations use the same type of messaging systems. As a result, problems may occur if a user tries to send a message to an external organization in an unsuitable format. Alternatively, you may want to configure Internet e-mail messaging formats at the organizational level if your organization wants to use a specific format or use features such as fonts and text color in e-mail communication.

You can configure the settings to send Internet e-mail messages to external domains on two levels:
  • By the user
  • By the domain
If you use the default settings, users can send e-mail messages in any format that they want. However, your organization may have policies about sending e-mail messages in HTML or Rich Text Format (RTF) format, and you may want to specify that all e-mail messages must be sent as plain text. Alternatively, you may have a partnership with another organization that is running Microsoft Exchange 2000 Server that can process HTML or RTF formats. In this scenario, you can configure a rule to deliver all e-mail messages to that domain using RTF format.


The following list describes the recommended hardware, software, network infrastructure, and service packs that you require:
  • Microsoft Windows 2000 Server Service Pack 3 (SP3)
  • Microsoft Active Directory directory service
  • Exchange 2003
This article assumes that you are familiar with the following topics:
  • Exchange System Manager
  • E-mail messaging formats such as plain text, RTF, and HTML

Description of messaging formats

When you configure the delivery of e-mail messages to external domains, make sure that you understand the various methods that you can be use.

Plain text

A plain text message is the most accepted form of messaging format. All e-mail message readers can display text messages in plain text format. However, plain text messages cannot display colors, different fonts, or emphasis such as bold or italic text.

Rich Text Format (RTF)

Exchange 2000 uses RTF messaging for messages that are delivered between Microsoft Outlook users. RTF displays colors, fonts, and formatting. However, RTF is only readable by Outlook. Exchange 2003 RTF format is different from the RTF format that is used in a word processor program such as Microsoft Word.

Note If a recipient receives a file attachment named Winmail.dat in their e-mail, that domain has an RTF incompatibility issue. To work around this issue, you must configure a rule that makes sure that messages that are sent to that domain do not use RTF format.

HTML format

HTML mail is a recent implementation that makes it possible to display rich content in a message. When you use the HTML mail format, the message is sent as an HTML page, complete with tags to change the appearance of the text. The recipient's e-mail client program then formats and displays the HTML. The major issue with HTML text is that not all e-mail client programs support HTML text. If the HTML e-mail message is not displayed correctly, the message can become unreadable.

Plain text and HTML

Exchange 2003 can send messages to external domains as both plain text and HTML. This format appears correctly on both types of client. However, the messages become two times as large and processing takes longer. You may be able to view both the plain text and the HTML in the replies to the message. This behavior frequently occurs in discussion groups where people have posted messages by using both plain text and HTML.

MIME and uuencode

MIME and user-to-user encoding (uuencode) are two different methods of sending binary attachments with messages. Early e-mail client programs used uuencode as the default message format. However, most current e-mail client programs support MIME. You may have to communicate with a domain that continues to use uuencode. In this scenario, you can configure a rule to deliver messages to that domain using the uuencode format.

Message text word wrapping

Although this format is not strictly an e-mail messaging format, some earlier versions of e-mail messaging clients require that a line break is placed after the seventy-sixth or seventy-seventh character. If you do not perform this procedure, those clients can only view the first 76 characters of each line. As a result, large portions of the message may not appear.

Configure e-mail messaging settings for all external domains

To configure the e-mail messages that you send to the majority of Internet domains, verify the settings for the default Internet e-mail messaging format. To do so, following these steps:
  1. Click Start, point to
    Programs, point to Microsoft Exchange, and then click System Manager.
  2. Expand Global Settings, and then click
    Internet Message Formats.
  3. In the right pane, right-click Default, and then click Properties.

    Note On the General tab of the Default properties, the SMTP domain for the default format is indicated as an asterisk (*) because this default entry sends e-mail messages to all Internet domains.
  4. Click the Message Format tab, and then click the message encoding you want to use under Message encoding.

    For most domains, use MIME for encoding and plain text for the message body.
  5. If you want users who connect by using non-Outlook mail clients to use the same message encoding settings, click to select the
    Apply content settings to non-MAPI clients check box.

    Post Office Protocol version 3 (POP3) clients frequently use Microsoft Outlook Express and may send messages in HTML format. You can force your non-MAPI clients to use plain text and then force a message format conversion to occur on the Exchange 2003 server.

    Note If many messages are converted in this manner, a large processing load may be created.
  6. Under Character sets, click the appropriate character set in the MIME and Non-MIME

    Note If you select the wrong character set, messages may not appear correctly.
  7. Click the Advanced tab, and then click the setting that you want to use under Exchange rich-text format.

    If you click Determined by individual user settings, the users can choose their own format. However, we do not recommend sending proprietary format to external parties. Therefore, you may want to enforce a plain-text only policy by selecting Never use.

    Note Exchange Rich Text Format (RTF) is a proprietary format which can only be interpreted by Outlook clients. Setting this option to Never use so that you can communicate with external parties will not affect the use of Exchange RTF format for interchange between Outlook users within your internal Exchange organization.
  8. Under Message text word wrap, click the message text word wrap setting you want to use.

    If you select
    Use at column, type the column where the word wrap occurs.
  9. Click OK to accept the settings, and then close the Default properties.
  10. Restart the SMTP Service

Configure settings for a domain running Exchange 2003 or Exchange 2000

If you send a significant number of e-mail messages to a domain that you know runs Exchange 2003 or Exchange 2000, you can improve the appearance of the messages that are sent to that domain by re-enabling Exchange 2003 RTF. To do so, follow these steps:
  1. Click Start, point to
    Programs, point to Microsoft Exchange, and then click System Manager.
  2. Expand Global Settings, right-click
    Internet Message Formats, point to New, and then click Domain.
  3. In the Name box, type a descriptive name for the object.
  4. In the SMTP domain box, type the name of the SMTP domain that you want this SMTP policy to apply to.
  5. Click the Message Format tab.
  6. Click MIME, and then click Provide message body as plain text.
  7. In the MIME and Non-MIMElists, click an appropriate character set. Typically, you use either of the following character sets:
    • US ASCII
    • Western European (ISO-8859-1)
  8. Click the Advanced tab, and then click
    Always Use.

    Note The message text word wrap setting remains as Never use.
  9. Click OK to accept the settings, and then close the Domain_Name properties.
  10. Restart the SMTP Service
You can configure more domains by using different settings as you require them.

Confirm that your Internet e-mail message settings function

To verify that your Internet e-mail message settings function correctly, send e-mail messages to external recipients and verify that they can receive and view the messages correctly. When the recipients reply, confirm that their messages appear correctly. If you send and receive messages from the domain that runs Exchange 2003 or Exchange 2000, the messages that are sent to and received from that domain preserve formatting such as colors and fonts.


Most issues that occur when you sent Internet e-mail messages occur with mail clients that cannot interpret RTF-formatted or HTML-formatted messages. To resolve this issue, either create a separate rule for that domain or change the default format to plain text.


For more information about how to configure Internet e-mail messaging formats in Exchange 2003, see the Exchange 2003 Resource Kit and Exchange 2003 Help.

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