Name

SendMimeErrors

Synopsis

MIME is documented in RFC2045 through RFC2049.[61] MIME is a method of incorporating non-ASCII text (such as images and sounds) in mail messages.

When sendmail composes an error notification of failed (bounced) mail, this SendMimeErrors option tells sendmail to include MIME-format headers in that error notification. MIME format is required for DSN notification to work (the two go hand in hand). This option affects only returned (bounced) mail.

If the SendMimeErrors option is true and if sendmail is composing a returned mail message, the following two headers are added to the header portion of that message: 

MIME-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status;
        boundary=magic

The 1.0 version of the MIME-Version: header (MIME-Version:) is hardcoded into V8 sendmail, so it cannot be changed. The Content-Type: is instead multipart/mixed if sendmail was compiled without DSN support (DSN). The magic of Content-Type: is a string that is used to separate the various parts of the message body. The string is formed from the queue ID, the time, and the hostname. For example: 

Content-Type: multipart/report; report-type=delivery-status; 
        boundary="dBPEYdx00413.946132480/your.host.domain"

Then sendmail prefixes the body of the returned message (if there is one), a line of notification, and this boundary: 

This is a MIME-encapsulated message

--dBPEYdx00413.946132480/your.host.domain
       ← message body begins here

Newer MUAs are aware of MIME and can send ...

Get Sendmail, 3rd Edition now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.

Start your free trial