Beginning with V8.10
sendmail, the
MaxMimeHeaderLength option (MaxMimeHeaderLength) can be used to define the maximum length for
selected MIME headers. Before making that check,
sendmail looks to see if a particular header is
in the class $={checkMIMEHeaders}. If it
isn't, sendmail skips this
length check.
When V8.10 sendmail starts up, it predefines the
$={checkMIMEHeaders} class to contain five MIME
headers: the Content-Disposition: header (Content-Disposition:); the Content-Id: header
(Content-Id:); the
Content-Transfer-Encoding: header (Content-Transfer-Encoding:); the Content-Type: header
(Content-Type:); and the
MIME-Version: header (MIME-Version:). You can add more headers with the
C or F configuration file
commands.
If any of these headers are found to be too long, they are truncated
to the length specified by the MaxMimeHeaderLength
option (MaxMimeHeaderLength). Note that this truncation is
done carefully so as to maintain the appearance of an RFC2822-legal
header.
