hermes
hermes is a mail server which uses postfix for SMTP/MTA dovecot-pigeonhole for IMAP/LMTP spamassassin for spam-assassining and sieve for server-side IMAP folder routing.
One of the main reasons why I wanted to deploy my own mailbox and mail exchanger is that I began to lose confidence in the way my data was being handled by public mail providers. I made this choice way before GDPR protects existed. Since I own my own domain (2 domains actually), I created a email alias naming convention to allow me to track which emails were being sent from who.
Email Aliases
Posfix is setup to use virtual domains and virtual aliases. This allowed me the greatest flexibility and also let me add my new domain as it was purchased later.
An example of the email alias naming convention is below:
bob.smith@secmayl.com
bob.smith.facebook@secmayl.com
bob.smith.twitter@secmayl.com
bob.smith.bmo@secmayl.com
bob.smith.government@secmayl.com
In the above, bob.smith@secmayl.com is the actual mailbox. The rest of the addresses are aliases. Now when Bob wants to give someone his email address, he needs to create the alias here in hermes before giving it out. When an email is received on the bob.smith.facebook@secmayl.com mailbox, it is sent to the bob.smith@secmayl.com mailbox, though the email message still contains the bob.smith.facebook@secmayl.com address in the header. Using this, we can confirm if an email received is suppose to be received on this alias.
Real-Life Example of Spam Tracking
An example of this is some spam I received on my nicholas.manios.cloudkilometers@secmayl.com alias which did not come from Cloud-Kilometers. I contacted both Cloud-Kilometers and the spamming company and asked how this email address came to be in the posession of the spamming company. Neither could answer for weeks, it was aparent that Cloud-Kilometers had broken Canadian Anti-Spam legislation and sold my email address without my permission.
After that, I was convinced that I would move all of my services to use this notation and currently have about 200 email alias created for services.