Yeah here you go on Debian. I just pasted this from my notes and added some formatting...
== set up mutt ==
$ sudo apt-get install mutt
$ echo "export EMAIL=user@domain.com" >> ~/.profile
$ source ~/.profile
== postfix ==
$ sudo apt-get install postfix
.. answer system mail name as your host name
.. add your domain to domains to accept email for
.. Follow instructions here WRT SPAM:
https://wiki.debian.org/Postfix#anti-spam:_smtp_restrictions
.. basically add two lines to /etc/postfix/main.cf
$ sudo service postfix restart
$ ufw allow 25 # allow smtp in firewall. I use ufw.
.. add your hostname as the MX for your domain (I use 123-reg)
.. Visit mxtoolbox.com and check the machine isn't an open relay and is functioning correctly
== procmail ==
$ sudo apt-get install procmail
.. add following to /etc/postfix/main.cf
mailbox_command = /usr/bin/procmail -f- -a "$USER"
$ sudo service postfix reload
== root alias ==
$ echo "root: youruseraccount" >> /etc/aliases
$ sudo newaliases
Done.
I genuinely get virtually no SPAM. RBLs and postfix sender validation above seems to work pretty well on its own.
I've done the same on OpenBSD with OpenSMTPd and spamd with even less effort.
Also, you spam statistic sounds way off for a setup that doesn't explicitly deal with spam.