The container provides a simple proxy relay for environments like Amazon VPC where you may have private servers with no Internet connection and therefore with no access to external mail relays (e.g. Amazon SES, SendGrid and others). You need to supply the container with your external mail relay address and credentials. The configuration is tested with Amazon SES.
This container runs under the s6 supervisor. Docker secrets are supported and the instructions for usage are included in the 'Variables' section.
Run the container with a command similar to the following:
$ docker run -d -h relay.example.com -e SMTP_LOGIN=<username> -e SMTP_PASSWORD=<password> -p 8025:25 b32147/smtp-relayThe container defaults to listening on port 25 but can be set to anything. The above example sets the container on the host's port 8025.
| Variable | Default | Description |
|---|---|---|
SMTP_LOGIN |
Login to connect to the external relay (required, otherwise the container fails to start) | |
SMTP_PASSWORD |
Password to connect to the external relay (required, otherwise the container fails to start) | |
EXT_RELAY_HOST |
email-smtp.us-east-1.amazonaws.com |
External relay DNS name |
EXT_RELAY_PORT |
587 |
External relay TCP port |
USE_TLS |
yes |
Remote require tls. Might be "yes" or "no" |
TLS_VERIFY |
may |
Trust level for checking the remote side cert. (none, may, encrypt, dane, dane-only, fingerprint, verify, secure). |
HOST_NAME |
relay.example.com |
A DNS name for this relay container (usually the same as the Docker's hostname) |
ACCEPTED_NETWORKS |
172.16.0.0/12 10.0.0.0/8 |
A network (or a list of networks) to accept mail from |
If using Docker Secrets, format the value of the argument as:
SMTP_LOGIN=/run/secrets/smtp-login
where smtp-login is the name of the secret created in Docker. This will read the secret at that location (should be /run/secrets/) and assign its contents to the original argument.