sendmail, 4th Edition

$={checkMIMEFieldHeaders}

MIME headers for maximum parameter length checking V8.10 and later

Beginning with V8.10 sendmail, the MaxMimeHeaderLength option (MaxMimeHeaderLength on page 1047) can be used to define the maximum length for the parameters that some MIME headers take. A parameter is separated from the main header name and value by a semicolon:

name: value  ;  parameter  ; parameter  ...

Before checking that parameter’s length, sendmail looks to see whether the header name is in the class $={checkMIMEFieldHeaders}. If it isn’t, sendmail skips the parameter length check.

When V8.10 sendmail starts up, it predefines the $={checkMIMEFieldHeaders} class to contain two MIME headers: the Content-Disposition: header (Content-Disposition: on page 1153); and the Content-Type: header (Content-Type: on page 1154). You can add more headers with the C or F configuration file command.

If any of these parameters are found to be too long, they are truncated to the limit imposed by the MaxMimeHeaderLength option (MaxMimeHeaderLength on page 1047).