I have taken to removing exim4 and installing either ssmtp or nullmailer
aptitude install ssmtp exim4- exim4-base- exim4-config- exim4-daemon-light-
Just enough MTA to get the word out. Since few people want/need a full MTA, this seems like
it should be the default. But I don't smart disk monitoring; a few years back I tried it and
it led to some unreliable system behavior.