POSTIN

/bin/sh

/usr/sbin/update-alternatives --install /usr/sbin/sendmail sendmail-command /usr/sbin/dma 5 --slave /usr/lib/sendmail sendmail-command-in_libdir /usr/sbin/dma

POSTUN

/bin/sh

if [ ! -e /usr/sbin/dma ]; then 
      /usr/sbin/update-alternatives --remove sendmail-command %{_sendmail_command}
fi