lits/docker-mail-relay repository overview

⁠Postfix Mail Relay

Contains:

• Postfix, running in a simple relay mode
• RSyslog

Processes are managed by supervisord, including cronjobs

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.

⁠Exports

• Postfix on 25

⁠Variables

• RELAY_HOST_NAME=relay.example.com: A DNS name for this relay container (usually the same as the Docker's hostname)
• ACCEPTED_NETWORKS=192.168.0.0/16 172.16.0.0/12 10.0.0.0/8: A network (or a list of networks) to accept mail from
• EXT_RELAY_HOST=email-smtp.us-east-1.amazonaws.com: External relay DNS name
• EXT_RELAY_PORT=25: External relay TCP port
• 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)
• USE_TLS=: Remote require tls. Might be "yes" or "no". Default: no.
• TLS_VERIFY=: Trust level for checking the remote side cert. (none, may, encrypt, dane, dane-only, fingerprint, verify, secure). Default: may.
• SMTPD_USE_TLS=: announce STARTTLS support to remote SMTP clients, but do not require that clients use TLS encryption. Might be "yes" or "no". Default: no.
• SMTPD_LOG_LVL=: Enable additional Postfix SMTP server logging of TLS activity. Might be "1,2,3,4". Do not use "2" or higher except in case of problems. Default: 0.

⁠Example

Launch Postfix container:

$ docker run -d -h relay.example.com --name="mailrelay" -e SMTP_LOGIN=myLogin -e SMTP_PASSWORD=myPassword -p 25:25 alterrebe/postfix-relay