# docker-smtp

> A self-hosted Docker image running Exim4 that lets containers send outgoing email directly or relay through a smart host like Gmail or SendGrid.

- **Category:** Email
- **Open source:** oss
- **Languages:** Shell
- **Platforms:** Docker, Docker Compose
- **Tags:** Email, SMTP, Docker, Exim, Mail Relay, Outgoing Mail

## Description

docker-smtp is a minimal Docker image maintained by Bytemark Hosting that provides an Exim4 SMTP server for containerized applications to send outgoing email. It can operate in two modes: as a direct delivery SMTP server sending mail straight to recipients, or as a smart host that authenticates and relays through an external SMTP provider such as Gmail or SendGrid. The image exposes port 25 and is configured via environment variables including MAILNAME, RELAY_HOST, RELAY_PORT, RELAY_USERNAME, RELAY_PASSWORD, and RELAY_NETS. It runs on any architecture with the Debian exim4-daemon-light package. The project has not been updated since 2018 and uses Debian Stretch as its base.

## Links

- [Homepage](https://github.com/BytemarkHosting/docker-smtp)
- [Docker](bytemark/smtp)
- [Issue Tracker](https://github.com/BytemarkHosting/docker-smtp/issues)
- [GitHub Repository](https://github.com/BytemarkHosting/docker-smtp)

---
Source: https://selfhost.directory/project/docker-smtp