Setting the primary and secondary character set groups

In the text parts of a MIME message, character set tags, such as US-ASCII or EUC-KR (Korean), specify how Domino® interprets the text data and renders it into recognizable characters. The value that represents a character in one character set can represent a different character in another character set.

About this task

When converting a MIME message into Notes® rich-text, Domino® uses the information in the character set tags to determine the appropriate characters for representing the message text. Similarly, when Domino® converts a Notes® rich-text message into MIME, it must determine which MIME character set tag to apply.

On the MIME - Basics tab of the Configuration Settings document, you can define a primary character set group and one or more secondary character set groups. These primary and secondary choices control, among other things, how Domino® detects character sets to correctly identify ambiguous text data in a message when converting inbound MIME messages to Notes® rich-text and outbound Notes® rich-text message to MIME.

Note: If your organization sends and receives messages that use US-ASCII characters only, there's no need to change the default settings.

Domino® can interpret text represented in 16 different character set groups (also known as language groups) including the Unicode standard for encoding character systems. A language group can correspond to a single language (for example, Japanese) or to a region where multiple languages use more or less the same characters (for example, Central Europe). A language group can also support multiple character sets.

For a list of supported character set groups and the language codes associated with them, see the related links.

If the MIME messages your organization receives always contained the correct character set information, there would be no need to change the default settings. However, some mail systems do not provide character set information when sending mail. For example, older mail systems may not support MIME at all, and some Web-based systems enable users to create messages in a given language but don't correctly generate MIME character set information when sending the message. Thus a user sending mail from a Web-based mail system might be able to compose and send messages written in Chinese, but in the sent message, the character set tag US-ASCII is incorrectly applied to the message text. If your SMTP server is configured to use the default character set group, it would be unable to correctly convert this message.

In such cases, Domino® examines incoming messages to determine the byte range used and identify unique control codes. It then attempts to match patterns in the incoming message to a probable character set. This process is effective in distinguishing among certain character sets only. For example, it can correctly distinguish messages in the CJKT languages (Simplified Chinese, Japanese, Korean, and Traditional Chinese ) from each other and from an English message), but it cannot distinguish between messages in English or any other Western languages, which tend to use the identical bytes and byte ranges.

To ensure accurate character set detection for the CJKT languages, configure a priority order among the languages by specifying a primary and secondary character. For example, if Domino® cannot distinguish whether a MIME message uses EUC-KR (a Korean character set) or GB2312 (a Simplified Chinese character set), it uses the priority order assigned to the primary and secondary character set groups to determine which character set to use in converting the message to Notes® rich-text. Domino® chooses the primary character set first, then the secondary character set (in an undefined order -- the order of multiple secondary choices doesn't matter), then the operating system group (for operating systems where the locale can be queried).

When converting outbound messages to MIME format, Domino® chooses a MIME character set based on the text of the message. Outbound messages are examined by the Router and the appropriate character set is selected for the message.


  1. Make sure you already have a Configuration Settings document for the server(s) to be configured.
  2. From the Domino® Administrator, click the Configuration tab and expand the Messaging section.
  3. Click Configurations.
  4. Select the Configuration Settings document for the mail server or servers you want to administer, and click Edit Configuration.
  5. Click the Basics tab, and in the field International MIME Settings for this document, select Enabled.
  6. Click the MIME > Basics tab.
  7. For the field Primary character set group, select the character set group for this domain's primary language. English is the default value. Choose the language or region appropriate for your organization, for example, Simplified Chinese.
  8. For the field Secondary character set groups, select the character set groups for other languages typically used in this domain. By default, no secondary character set group is configured. Choose the language or region(s) appropriate for your organization, for example, Western. You can specify multiple secondary character set groups.
  9. Click Save & Close.
  10. The change takes effect after the next Router configuration update. To put the new setting into effect immediately, reload the routing configuration.