FROM debian:12-slim

ENV DEBIAN_FRONTEND=noninteractive

RUN apt-get update && apt-get install -y --no-install-recommends \
    postfix \
    ca-certificates \
    sasl2-bin \
    libsasl2-modules \
    netcat-openbsd \
  && rm -rf /var/lib/apt/lists/* \
  && (getent group postdrop || groupadd -r postdrop) \
  && usermod -aG postdrop postfix \
  # /etc/sasldb2 es root:sasl 0640: sin este grupo, smtpd no puede abrirlo y
  # devuelve "454 4.7.0 Temporary authentication failure: generic failure"
  # (incidente 2026-07-29, fallo 3).
  && (getent group sasl || groupadd -r sasl) \
  && usermod -aG sasl postfix

COPY main.cf /etc/postfix/main.cf
COPY master.cf /etc/postfix/master.cf
COPY smtpd.conf /etc/postfix/sasl/smtpd.conf
COPY entrypoint.sh /entrypoint.sh
RUN chmod +x /entrypoint.sh

EXPOSE 25 587
ENTRYPOINT ["/entrypoint.sh"]