MMDF approaches administrative configuration differently than other popular MTAs. In the choice between placing specialized knowledge into the software, versus requiring that it be created through administrator's configuration instructions, MMDF chose the former. Hence, arbitrary header rewriting is performed by hard-coded software, with configuration limited to choices among existing rewriting alternatives. This makes configuration simpler and safer for administrators, who use simple key-value textual tables. It also takes more effort to create a new rewriting choice, but that effort needs to occur only one time, by a single technical expert.