Mail Forwarder

--------------

The ``mail_forwarder`` role can be used for setting-up a local SMTP server for

sending out mails and receiving mails for local users. The SMTP server is

provided by Postfix.

SMTP service on server set-up this way is not meant to be exposed to the

Internet directly, and should receive delivery failures from the relay server

instead.

The role implements the following:

* Installs and configures Postfix.

* Purges Exim4 configuration (just in case).

* Sets-up aliases for the local recipients.

Postfix is configured as follows:

* Local destinations are set-up.

* A relay host is set.

Parameters

~~~~~~~~~~

**local_mail_aliases** (dictionary, mandatory)

  Dictionary defining the local aliases. Aliases defined this way will either be

  appended to default aliases on the server, or replace the existing entries (if

  the alias/recipient is already present). Keys in the dictionary are the local

  recipients/aliases, while the value provided should be a space-separated list

  of mail addresses (or local users) where the mails should be forwarded.

**smtp_relay_host** (string, mandatory)

  SMTP server via which the mails are sent out for non-local recipients.

Examples

~~~~~~~~

Here is an example configuration for setting-up the mail forwarder:

.. code-block:: yaml

  ---

  # All mails sent to local user root will be forwarded to external account as

  # well.

  local_mail_aliases:

    root: "root john.doe@example.com"

  smtp_relay_host: mail.example.com

mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128