Dovecot Configuration

[Mischback]

Relevant Dovecot settings

• [x] 10-auth.conf
  • [x] auth_mechanism: Outlook requires login, plain is the default
  • [x] review the different authentication backends with Dovecot's documentation
• [x] 10-mail.conf
  • [x] mail_location
  • guide suggests maildir:~/Maildir, but as we are (mainly) concerned about virtual users, how does this work?
  • [x] mail_plugins: add quota to manage the size of users' mailboxes
• [x] 10-master.conf
  • [x] provide the authentication socket required by Postfix:

    # Postfix smtp-auth
    unix_listener /var/spool/postfix/private/auth {
    mode = 0660
    user = postfix
    group = postfix
    }

  • [x] create the lmtp socket for Postfix (might already be there, configure accordingly)

    service lmtp {
    unix_listener /var/spool/postfix/private/dovecot-lmtp {
    group = postfix
    mode = 0600
    user = postfix
    }
    }

  • [x] review other settings here!
• [x] 10-ssl.conf
  • [x] ssl_cert and ssl_key: Point to the respective files
  • [x] IMPORTANT syntax is like ssl_cert = </etc/letsencrypt/live/webmail.example.org/fullchain.pem, making the content of the certificate available!
• 20-lmtp.conf
  • if server side sieve should be applied, activate the plugin here (needs packet installation)
  • tracked in #21

• [x] 90-quota.conf

  • [x] Provide the actual mailbox quota

    plugin {
    quota = maildir:User quota
    
    quota_status_success = DUNNO
    quota_status_nouser = DUNNO
    quota_status_overquota = "452 4.2.2 Mailbox is full and cannot receive any more emails"
    }

  • [x] provide the endpoint (socket) for Postfix

    service quota-status {
    executable = /usr/lib/dovecot/quota-status -p postfix
    unix_listener /var/spool/postfix/private/quota-status {
    user = postfix
    }
    }

  • [x] Why is the definition of unix_listener lacking mode and group settings, as they are present in the other socket definitions?
  • [x] the actual quota must be provided by the user_db; needs investigation!
  • [x] Enable warnings about quotas:

    plugin {
    quota_warning = storage=95%% quota-warning 95 %u
    quota_warning2 = storage=80%% quota-warning 80 %u
    }
    service quota-warning {
    executable = script /usr/local/bin/quota-warning.sh  # Adjust script path!
    unix_listener quota-warning {
     user = vmail
     group = vmail
     mode = 0660
    }
    }

  • [x] The referenced script to send the users emails about their quotas:

    
    #!/bin/sh
    PERCENT=$1
    USER=$2
    cat << EOF | /usr/lib/dovecot/dovecot-lda -d $USER -o "plugin/quota=maildir:User quota:noenforcing"
    From: postmaster@webmail.example.org
    Subject: Quota warning - $PERCENT% reached

  Your mailbox can only store a limited amount of emails. Currently it is $PERCENT% full. If you reach 100% then new emails cannot be stored. Thanks for your understanding. EOF

• [x] Important somewhere is the user_db setting. This needs careful attention, because my setup will not rely on SQL as backend (deviating from the tutorial!); see https://doc.dovecot.org/configuration_manual/authentication/user_databases_userdb/ and https://doc.dovecot.org/configuration_manual/authentication/passwd_file/#authentication-passwd-file

[Mischback]

Basic implementation completed as of f749eb01c201f1f5d85f6997177c45bd0d1cd80b

• Dovecot is up and running
• Dovecot is providing user-management for Postfix
• Dovecot is providing IMAP / POP3 (with default settings)
• Dovecot is working as Postfix's LDA