Postfix relay

18 17

01 May, 2024

Shell

What is Postfix Mail Relay ?

Postfix Mail Relay is a simple SMTP relay, originally based on alterrebe/docker-mail-relay, but has been rewritten since.

Description

The container provides a simple SMTP 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 image is tested with Amazon SES, Sendgrid, Gmail and Mandrill

Changes since `alterrebe/docker-mail-relay`

Uses alpine image instead of ubuntu.
Uses envsubst for templating instead of j2cli.
All output goes to stdout and stderr including maillog.
Included superviserd event watcher which will exit the supervisord process if one of the monitored processes dies unexpectedly.
Doesn’t use TLS on smtpd side.
And other changes to make the image as KISS as possible

Changed in version `1.3.0`

Remove rsyslog dependancy
Remove supervisor
Even more KISS, just single script used to configure and run postfix

Environment variables

ENV. Variable	Description
`ACCEPTED_NETWORKS`	Space delimited list of networks to accept mail from. Default: `192.168.0.0/16 172.16.0.0/12 10.0.0.0/8`
`RECIPIENT_RESTRICTIONS`	Space delimited list of allowed `RCPT TO` addresses. Default: unrestricted
`SMTP_HOST`	External relay DNS name. Default: `email-smtp.us-east-1.amazonaws.com`
`SMTP_LOGIN`	Login to connect to the external relay. Required
`SMTP_PASSWORD`	Password to connect to the external relay. Required
`SMTP_PORT`	External relay TCP port. Default: `25`
`TLS_VERIFY`	Trust level for checking remote side cert. Default: `may` (http://www.postfix.org/postconf.5.html#smtp_tls_security_level)
`USE_TLS`	Remote require tls. Must be `yes` or `no`. Default: `no`

Exposed port(s)

Postfix on port 25

Example

Launch Postfix container:

docker run -d -h relay.example.com --name="mailrelay" \
    -e RECIPIENT_RESTRICTIONS="gmail.com [email protected]" \
    -e SMTP_LOGIN=myLogin \
    -e SMTP_PASSWORD=myPassword \
    -p 25:25 \
    simenduev/postfix-relay