Relabelling MIME header lines

Some user agents or gateways may emit messages with MIME header lines which are less informative than they might be, but which nevertheless  contain enough information to construct more precise MIME header lines. Although the best solution is to properly configure such user agents or gateways, if they are not under your control, you can instead ask the  MTA to try to reconstruct more useful MIME header lines.

If the first probe of the    mapping table yields a  "Yes" or "Always" keyword, then the MTA will check  for the existence of any conversions entries. (In Unified Configuration, the MTA checks for the existence of any  entries; in legacy configuration, the MTA checks for the existence of a conversions  file,  .)  If any conversions entries exist, then  the MTA will look for an entry with RELABEL=1 and if it finds  such an entry, the MTA will then perform any MIME relabellings  specified in the entry. (See Conversion control for additional details on conversions entries.)

New in 7.0.5, in addition to MIME relabellings, RELABEL=1 can also perform encoding changes (OUT-ENCODING clauses will be applied);  formerly, OUT-ENCODING had no effect in RELABEL=1 entries.

For instance, the combination of a  mapping table of: msconfig&#x3e; show mapping:CHARSET-CONVERSION role.mapping:CHARSET-CONVERSION.rule = IN-CHAN=tcp_&#x2a;;OUT-CHAN=ims-ms;CONVERT Yes and conversions entries (use &#x27;s   command to create such entries from within  ) of: out-chan=ims-ms; in-type=application; in-subtype=octet-stream; in-parameter-name-0=name; in-parameter-value-0=&#x2a;.ps; out-type=application; out-subtype=postscript; parameter-copy-0=&#x2a;; relabel=1 out-chan=ims-ms; in-type=application; in-subtype=octet-stream; in-disposition=attachment; in-dparameter-name-0=filename; in-dparameter-value-0=&#x2a;.ps; out-type=application; out-subtype=postscript; out-disposition=attachment; dparameter-copy-0=&#x2a;; relabel=1 out-chan=ims-ms; in-type=application; in-subtype=octet-stream; in-parameter-name-0=name; in-parameter-value-0=&#x2a;.msw; out-type=application; out-subtype=msword; parameter-copy-0=&#x2a;; relabel=1 out-chan=ims-ms; in-type=application; in-subtype=octet-stream; in-disposition=attachment; in-dparameter-name-0=filename; in-dparameter-value-0=&#x2a;.msw; out-type=application; out-subtype=msword; out-disposition=attachment; dparameter-copy-0=&#x2a;; relabel=1 will result in messages that arrive on a  channel and are  routed to the   channel, and that arrive originally with MIME labelling of application/octet-stream but have a filename parameter with the extension   or , being relabelled as application/postscript or application/msword, respectively. (Note that this more precise labelling is what the original user agent or gateway should have performed itself.)

See also:
 * CHARSET-CONVERSION mapping table
 * conversions MTA Option
 * Conversion control
 * Message reformatting