matrix-docker-ansible-deploy/docs/configuring-playbook-email.md

<!--
SPDX-FileCopyrightText: 2018 - 2024 Slavi Pantaleev
SPDX-FileCopyrightText: 2019 Eduardo Beltrame
SPDX-FileCopyrightText: 2020 - 2025 MDAD project contributors
SPDX-FileCopyrightText: 2024 - 2025 Suguru Hirahara

SPDX-License-Identifier: AGPL-3.0-or-later
-->

# Adjusting email-sending settings (optional)

By default, this playbook sets up an [Exim](https://www.exim.org/) relay SMTP mailer service (powered by [exim-relay](https://github.com/devture/exim-relay) and the [ansible-role-exim-relay](https://github.com/mother-of-all-self-hosting/ansible-role-exim-relay) Ansible role), through which all Matrix services send emails.

**With the default setting, exim-relay attempts to deliver emails directly with the address `matrix@matrix.example.com`**, as specified by the `exim_relay_sender_address` playbook variable. See below if you want to configure the playbook to relay email through another SMTP server.

The Ansible role for exim-relay is developed and maintained by [the MASH (mother-of-all-self-hosting) project](https://github.com/mother-of-all-self-hosting/ansible-role-exim-relay). For details about configuring exim-relay, you can check them via:
- 🌐 [the role's documentation at the MASH project](https://github.com/mother-of-all-self-hosting/ansible-role-exim-relay/blob/main/docs/configuring-exim-relay.md) online
- 📁 `roles/galaxy/exim_relay/docs/configuring-exim-relay.md` locally, if you have [fetched the Ansible roles](installing.md#update-ansible-roles)

## Firewall settings

No matter whether you send email directly (the default) or you relay email through another host, you'll probably need to allow outgoing traffic for TCP ports 25/587 (depending on configuration).

## Adjusting the playbook configuration

### Relaying email through another SMTP server (optional)

By default, exim-relay attempts to deliver emails directly. This may or may not work, depending on your domain configuration (SPF settings, etc.)

**On some cloud providers such as Google Cloud, [port 25 is always blocked](https://cloud.google.com/compute/docs/tutorials/sending-mail/), so sending email directly from your server is not possible.** In this case, you will need to relay email through another SMTP server.

For details about configuration, refer [this section](https://github.com/mother-of-all-self-hosting/ansible-role-exim-relay/blob/main/docs/configuring-exim-relay.md#relaying-email-through-another-smtp-server) on the role's document.

💡 To improve deliverability, we recommend relaying email through another SMTP server anyway.

## Troubleshooting

See [this section](https://github.com/mother-of-all-self-hosting/ansible-role-exim-relay/blob/main/docs/configuring-exim-relay.md#troubleshooting) on the role's documentation for details.