V8 sendmail offers a number of m4 macros for use in your mc configuration file that deal directly with headers. They are shown in Table 25-4.
Macro
§
Sets What
confFROM_HEADER
From:
Define the format for the From: header
confRECEIVED_HEADER
Received:
Define the format for the Received: header
confOLD_STYLE_HEADERS
OldStyleHeaders
Declare the OldStyleHeaders option
confMAX_HEADERS_LENGTH
MaxHeadersLength
Declare the MaxHeadersLength option
confMAX_MIME_HEADER_LENGTH
MaxMimeHeaderLength
Declare the MaxMimeHeaderLength option
confSINGLE_LINE_FROM_HEADER
SingleLineFromHeader
Declare the SingleLineFromHeader option
confUSE_ERRORS_TO
UseErrorsTo
Declare the UseErrorsTo option, which affects the Errors-To: header
confNO_RCPT_ACTION
NoRecipientAction
Declare the NoRecipientAction option, which affects the To: , Cc: , and Bcc: headers
confRRT_IMPLIES_DSN
RrtImpliesDsn
Declare the RrtImpliesDsn option, which affects the Return-Receipt-To: header