The MTA can convert various nonstandard message formats to MIME using the Yes CHARSET-CONVERSION. In particular, the RFC 1154 format uses a nonstandard Encoding: header line. However, some gateways emit incorrect information on this header line, with the result that sometimes it is desirable to ignore this header line. The ignoreencoding keyword instructs the MTA to ignore any Encoding: header line.
Unless the MTA has a CHARSET-CONVERSION enabled, such headers are ignored in any case. The interpretencoding keyword instructs the MTA to pay attention to any Encoding: header line, if otherwise configured to do so, and is the default.