I am looking for a reliable step by step process for setting up an email server located on an existing website server. I have installed; exim4 light, dovecot, Thunderbird, OpenSSL, and TLS security. I have tried following several bits of documentation regarding this with some success, but as with every time I try this, I open up my system to SPAM at a ridiculous rate. I want to eliminate that and get this mail server fully operational.
I am seeking a well-documented approach that I can follow. I am using current Debian Stretch and the server is primarily a Mediawiki system where I NEED mail available.
Any tips are appreciated.
Thanks!
John