github.com/tiredofit/docker-postfix-relay
About
Dockerfile to build a Postfix SMTP server used for relaying messages to an external SMTP server.
- Supports Authentication to remote server
- Persistent Data Spool and Storage
- Option for daily log file summaries
Maintainer
Prerequisites and Assumptions
- Remote SMTP Host
Installation
Build from Source
Clone this repository and build the image with docker build <arguments> (imagename) .
Prebuilt Images
Builds of the image are available on Docker Hub and is the recommended method of installation.
The following image tags are available along with their tagged release based on what's written in the Changelog:
| Container OS | Tag |
|---|---|
| Alpine | :latest |
Multi Architecture
Images are built primarily for amd64 architecture, and may also include builds for arm/v7, arm64 and others. These variants are all unsupported. Consider sponsoring my work so that I can work with various hardware. To see if this image supports multiple architecures, type docker manifest (image):(tag)
Configuration
Quick Start
-
The quickest way to get started is using docker-compose. See the examples folder for a working docker-compose.yml that can be modified for development or production use.
-
Set various environment variables to understand the capabilities of this image.
-
Map persistent storage for access to configuration and data files for backup.
Persistent Storage
The following directories are used for configuration and can be mapped for persistent storage.
| Directory | Description |
|---|---|
/data/ |
Postfix spool and queue |
/logs/ |
Logfiles |
Environment Variables
Base Images used
This image relies on an Alpine Linux base image that relies on an init system for added capabilities. Outgoing SMTP capabilities are handlded via msmtp. Individual container performance monitoring is performed by zabbix-agent. Additional tools include: bash,curl,less,logrotate, nano,vim.
Be sure to view the following repositories to understand all the customizable options:
| Image | Description |
|---|---|
| OS Base | Customized Image based on Alpine Linux |
| Parameter | Description | Default |
|---|---|---|
ACCEPTED_NETWORKS |
Who to allow access to relay | 172.16.0.0/12 |
DATA_LOCATION |
Where the spool and other persistent files are stored | /data/ |
ENABLE_AUTH |
Enable Authentication to remove SMTP host | TRUE |
ENABLE_HEADER_CHECKS |
Enable header checking | TRUE |
ENABLE_SMTP_HEADER_CHECKS |
Enable header checking for SMTP | TRUE |
LOG_FILE |
Log File name | postfix.log |
LOG_PATH |
Log Locations | /logs/ |
LOG_TYPE |
Output logs to FILE or CONSOLE |
FILE |
LOG_SUBJECT |
Log Subject Line | TRUE |
LOG_SUBJECT_SMTP |
Log Subject Line for SMTP | TRUE |
LOG_SUMMARY |
Create daily log summaries in LOG_PATH/summary of activity |
TRUE |
SMTP_HOST |
The SMTP Host to forward mails to (e.g. mail.hostname.com) | |
SMTP_USER |
The username for authentication to remote SMTP (e.g. [email protected]) | |
SMTP_PASS |
The password for above username (e.g. password) | |
SERVER_NAME |
The hostname to identify ourselves to the remote SMTP Server (e.g. yourhost.hostname.com) | example.com |
TLS_VERIFY |
Trust Level for checking remote cert none may encrypt dane dane-only fingerprint verify secure |
may |
USE_TLS |
Use TLS when sending yes or no |
no |
Networking
| Port | Description |
|---|---|
25 |
SMTP |
Maintenance
Shell Access
For debugging and maintenance purposes you may want access the containers shell.
bash docker exec -it (whatever your container name is) bash
Support
These images were built to serve a specific need in a production environment and gradually have had more functionality added based on requests from the community.
Usage
- The Discussions board is a great place for working with the community on tips and tricks of using this image.
- Consider sponsoring me personalized support.
Bugfixes
- Please, submit a Bug Report if something isn't working as expected. I'll do my best to issue a fix in short order.
Feature Requests
- Feel free to submit a feature request, however there is no guarantee that it will be added, or at what timeline.
- Consider sponsoring me regarding development of features.
Updates
- Best effort to track upstream changes, More priority if I am actively using the image in a production environment.
- Consider sponsoring me for up to date releases.
License
MIT. See LICENSE for more details.