I use dovecot for this. And thunderbird to actually move/archive the emails. I use caddy for many of my services, so I have pointed dovecot to caddys certificates (for “my.domain”), since it manages certificates through let’s encrypt. I had a plan to install postfix for sending internal emails from my self-hosted services, but it seemed like a bit of configuration and I got busy with other stuff

I made an excerpt from my docker-compose.yml, but you probably have to figure out some things on your own

version: '3.4'

services:
  dovecot:
    image: dovecot/dovecot:2.3.20
    restart: unless-stopped
    volumes:
      - ./dovecot/:/etc/dovecot
      - /mnt/storage/dovecot/mail:/srv/mail
      - ./caddy/data/caddy/certificates/acme-v02.api.letsencrypt.org-directory/wildcard_.my.domain/wildcard_.my.domain.crt:/etc/ssl/cert.crt
      - ./caddy/data/caddy/certificates/acme-v02.api.letsencrypt.org-directory/wildcard_.my.domain/wildcard_.my.domain.key:/etc/ssl/key.key
    ports:
      - 993:993

contents of ./dovecot folder:

dovecot.conf
passwords

contents of dovecot.conf (I think I searched online to find a good example, I don’t remember where from…)

## manage this file

mail_home=/srv/mail/%Lu
mail_location=sdbox:~/Mail
mail_uid=1000
mail_gid=1000

protocols = imap pop3 submission sieve lmtp

first_valid_uid = 1000
last_valid_uid = 1000

passdb {
  driver = passwd-file
  args = scheme=argon2i /etc/dovecot/passwords
}

ssl=yes
ssl_cert=</etc/ssl/cert.crt
ssl_key=</etc/ssl/key.key

namespace {
  inbox = yes
  separator = /

  mailbox Drafts {
    auto = subscribe
    special_use = \Drafts
  }
  mailbox Sent {
    auto = subscribe
    special_use = \Sent
  }
  mailbox Spam {
    auto = subscribe
    special_use = \Junk
  }
  mailbox Trash {
    auto = subscribe
    special_use = \Trash
  }
  mailbox Archive {
    auto = subscribe
    special_use = \Archive
  }
}

service lmtp {
  inet_listener {
    port = 24
  }
}

listen = *

log_path=/dev/stdout
info_log_path=/dev/stdout
debug_log_path=/dev/stdout