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 local environments where you can have private servers without an Internet connection and, therefore, without access to external mail retransmissions. You must provide the container with your external mail relay address and your credentials. The configuration is done on Office 365, but it can work with any type of server.

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=smtp.office365.com: External relay DNS name
EXT_RELAY_PORT=587: 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: yes.
TLS_VERIFY=: Trust level for checking the remote side cert. (none, may, encrypt, dane, dane-only, fingerprint, verify, secure). Default: may.

Example

Launch Postfix container:

$ docker run -d -h docker01.hpcmc.local --name="dockermailrelay" \
-e SMTP_LOGIN="relay@my-tenant-office365.onmicrosoft.com" \
-e SMTP_PASSWORD="30#cc+/XEKcf" \
-e EXT_RELAY_HOST="smtp.office365.com" \
-e EXT_RELAY_PORT="587" \
-e ACCEPTED_NETWORKS="10.21.92.72" \
-p 25:25 denispaiva/relay-smtp-postfix-office365

License

"relay-smtp-postfix-office365" is licensed under the MIT license. See LICENSE for the full license text.