FROM alpine:edge
RUN apk --update --no-cache add opensmtpd openssl && \
    install -d -m 0711 -v /var/spool/smtpd && \
    openssl req -newkey rsa:4096 -nodes -keyout /etc/ssl/serverkey.pem -x509 -days 365 -subj "/CN=smtprelay.codehal.de" -out /etc/ssl/servercert.pem
ENTRYPOINT smtpd -d