Mailu configuration settings ============================ Common configuration -------------------- The ``SECRET_KEY`` **must** be changed for every setup and set to a 16 bytes randomly generated value. It is intended to secure authentication cookies among other critical uses. The ``DOMAIN`` holds the main e-mail domain for the server. This email domain is used for bounce emails, for generating the postmaster email and other technical addresses. The ``HOSTNAMES`` are all public hostnames for the mail server. Mailu supports a mail server with multiple hostnames. The first declared hostname is the main hostname and will be exposed over SMTP, IMAP, etc. The ``POSTMASTER`` is the local part of the postmaster email address. It is recommended to setup a generic value and later configure a mail alias for that address. The ``AUTH_RATELIMIT`` holds a security setting for fighting attackers that try to guess user passwords. The value is the limit of requests that a single IP address can perform against IMAP, POP and SMTP authentication endpoints. Mail settings ------------- The ``MESSAGE_SIZE_LIMIT`` is the maximum size of a single email. It should not be too low to avoid dropping legitimate emails and should not be too high to avoid filling the disks with large junk emails. The ``RELAYNETS`` are network addresses for which mail is relayed for free with no authentication required. This should be used with great care. It is recommended to include your Docker internal network addresses if other Docker containers use Mailu as their mail relay. The ``RELAYHOST`` is an optional address of a mail server relaying all outgoing mail. The ``FETCHMAIL_DELAY`` is a delay (in seconds) for the fetchmail service to go and fetch new email if available. Do not use too short delays if you do not want to be blacklisted by external services, but not too long delays if you want to receive your email in time. The ``RECIPIENT_DELIMITED`` is a character used to delimit localpart from a custom address part. For instance, if set to ``+``, users can use addresses like ``localpart+custom@domain.tld`` to deliver mail to ``localpart@domain.tld``. This is useful to provide external parties with different email addresses and later classify incoming mail based on the custom part. The ``DMAR_RUA`` and ``DMARC_RUF`` are DMARC protocol specific values. They hold the localpart for DMARC rua and ruf email addresses. Web settings ------------ The ``WEB_ADMIN`` contains the path to the main admin interface, while ``WEB_WEBMAIL`` contains the path to the Web email client. Both ``SITENAME`` and ``WEBSITE`` are customization options for the panel menu in the admin interface, while ``SITENAME`` is a customization option for every Web interface. Advanced settings ----------------- The ``PASSWORD_SCHEME`` is the password encryption scheme. You should use the default value, unless you are importing password from a separate system and want to keep using the old password encryption scheme.