Building the image

docker build --rm -t postfix:latest .

Running the image

docker run -it --rm --name test -p 25:25 -p 587:587 postfix:latest

Environment variables

These values are default and can be overriden by declaring environment variable with naother value.

# The text that follows the 220 status code in the SMTP greeting banner.
POSTFIX_SMTP_BANNER="$myhostname ESMTP $mail_name ($mail_version)"

# Enable submission running on port 587.
POSTFIX_SUBMISSION_ENABLED="yes"

# Enable standard non encrypted SMTP running on port 25.
POSTFIX_SMTP_ENABLED="yes"

# Enable SSL encrypted SMTPS running on port 465.
POSTFIX_SMTPS_ENABLED="yes"

# Opportunistic TLS: announce STARTTLS support to remote SMTP clients, but do not require that clients use TLS encryption.
POSTFIX_SMTPD_USE_TLS="no"

# When TLS encryption is optional in the Postfix SMTP server, do not announce or accept SASL authentication over unencrypted connections.
POSTFIX_SMTPD_TLS_AUTH_ONLY="yes"

# File with the Postfix SMTP server RSA certificate in PEM format.
POSTFIX_SMTPD_TLS_CERT_FILE="/etc/ssl/certs/ssl-cert-snakeoil.pem"

# File with the Postfix SMTP server RSA private key in PEM format.
POSTFIX_SMTPD_TLS_KEY_FILE="/etc/ssl/private/ssl-cert-snakeoil.key"

# The SMTP TLS security level for the Postfix SMTP server.
POSTFIX_SMTPD_TLS_SECURITY_LEVEL="may"

# Directory with PEM format Certification Authority certificates.
POSTFIX_SMTP_TLS_CAPATH="/etc/ssl/certs"

# The default SMTP TLS security level for the Postfix SMTP client.
POSTFIX_SMTP_TLS_SECURITY_LEVEL="encrypt"

# The internet hostname of this mail system.
POSTFIX_MYHOSTNAME="$(hostname --fqdn)"

# The internet hostname of this mail system.
POSTFIX_MYDOMAIN="$(hostname --fqdn)"

# The list of "trusted" remote SMTP clients that have more privileges than "strangers".
POSTFIX_MYNETWORKS="127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 192.168.0.0/16 172.16.0.0/12 10.0.0.0/8"

# The local network interface addresses that this mail system receives mail on.
POSTFIX_INET_INTERFACES="all"

# The Internet protocols Postfix will attempt to use when making or accepting connections.
POSTFIX_INET_PROTOCOLS="all"

# A list of Milter (mail filter) applications for new mail that arrives via the Postfix smtpd server.
POSTFIX_SMTPD_MILTERS="opendkim:port"

# A list of Milter (mail filter) applications for new mail that does not arrive via the Postfix smtpd server.
POSTFIX_NON_SMTPD_MILTERS="opendkim:port"