Configure the postfix-generic, postfix-main.cf and sasl-passwd files with your information.
Change the user@domain.com to match your email account you plan on using to send emails to Office 365.
Change the mydomain and mynetworks to match your domain and network. Add your SSL certificate and key to the secrets directory if you plan on using TLS.
Add your Office 365 SMTP username and password to the file.
cd ./postfix-alpine
docker build -t postfix-alpine .docker run -d \
--rm \
--init \
--env POSTFIX_SMTP_HELO_NAME=mail-relay \
--env POSTFIX_MYORIGIN=mail-relay \
--env POSTFIX_MYHOSTNAME=mail-relay \
--hostname mail-relay \
--name postfix-alpine postfix-alpine \
--p 8587:587 \
postfix-alpine:latest