forward/reply solution for internal mails

DMS/Dockerfile.custom

@@ -0,0 +1,21 @@
+FROM docker.io/mailserver/docker-mailserver:latest
+
+LABEL maintainer="andreas@knuth.dev"
+LABEL description="Custom DMS with content filter support"
+
+# Install Python and boto3
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends \
+        python3 \
+        python3-pip \
+    && pip3 install --no-cache-dir boto3 \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/*
+
+# Copy content filter script
+COPY content_filter.py /usr/local/bin/content_filter.py
+RUN chmod +x /usr/local/bin/content_filter.py
+
+# Create log file with correct permissions
+RUN touch /var/log/mail/content_filter.log && \
+    chown mail:mail /var/log/mail/content_filter.log