MDN language and customization
There are a number of localizable, customizable files the MTA consults when constructing MDNs; these files will be discussed further in Customizing MDNs via the disposition files. By default, if no
DISPOSITION_LANGUAGE mapping table is configured, the
disposition_*.* files located in the
langdir directory will be used to generate all MDNs. However, separate sets of
disposition_*.* files can be created and located in separate directories---for localization or site customization purposes. Indeed, the MTA is distributed with several sets of langauge-specific
disposition_*.* files, and a basic
DISPOSITION_LANGUAGE mapping table (referenced in the mappings file via file inclusion of the
mappings.locale file) which selects among the language-specific directories based on language preference of original message senders. That is, the
DISPOSITION_LANGUAGE mapping table selects, based on any language preference of the original message sender, a directory in which to find an appropriate set of
disposition_*.* files for generating an MDN back to that sender.
Probes to the DISPOSITION_LANGUAGE mapping table have the form:
mdn-type can be any of
failed, and where
modifier can be a comma-separated list including any of
accept-language field will have any values (possibly a comma-separated list) found on (preferentially) an Accept-Language: header line, or if that header line is not present then from a Preferred-language: header line if present, or failing that an X-Accept-Language: header line. Note that valid language tag values are discussed in RFC 3066 (Tags for the Identification of Languages).
The pattern (right hand side) of a
DISPOSITION_LANGUAGE entry may set the
$I flag to specify the directory from which the MTA should use
disposition_*.* files when constructing an MDN, and optionally following a vertical bar character a destination charset. The pattern may also optionally use the
$T flag to set the Subject: field value to use when constructing this MDN; the Subject: field follows yet another vertical bar character. (Note that the
$T Subject: will only be used if there is neither a specific Subject: field for this type of MDN (such as a Sieve "
vacation :subject" might specify), nor a SUBJECT option set in the
disposition_option.opt file. That is, the
$T specified Subject: field value is of low precedence compared to the other ways of setting the Subject: field value.) The pattern may also optionally set the names of the files to use when constructing this MDN instead of the normal
disposition_suffix.txt files; these are specified following the directory specification but prior to the first vertical bar character, with comma separators. All together, the syntax of the pattern is:
See Sample NOTIFICATION_LANGUAGE and DISPOSITION_LANGUAGE mapping tables for an example
DISPOSITION_LANGUAGE mapping table.
Note that as of MS 7.0.5, all MDNs generated by the MTA include an Auto-Submitted: header line, per the recommendation of RFC 3834 (Recommendations for Automatic Responses to Electronic Mail) -- in prior versions only certain forms of MDNs contained such a header line -- and the value placed on the Auto-submitted: header line has been updated to include the additional information suggested in RFC 5436 (Sieve Notification Mechanism: mailto) including additional values (such as
auto-notified) and the