Improve modular setup for DKIM

Start Amavis integration

amavis/Dockerfile

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+FROM ubuntu:14.10
+
+ENV DEBIAN_FRONTEND noninteractive
+RUN locale-gen en_GB en_GB.UTF-8 && dpkg-reconfigure locales
+
+# Prerequisites
+RUN apt-get update && apt-get install -y \
+    amavisd-new \
+    spamassassin \
+    libnet-dns-perl \
+    libmail-spf-perl \
+    pyzor \
+    razor && \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+
+# Set up razor and pyzor
+RUN su - amavis -s /bin/bash && razor-admin -create && razor-admin -register && pyzor discover
+
+COPY ./config/amavis-content_filter_mode /etc/amavis/conf.d/15-content_filter_mode
+
+# Nice place for your settings
+VOLUME ["/mail_settings"]
+
+# Configure boot script
+COPY boot /
+RUN chmod 755 /boot
+
+ENV AMAVIS=true
+
+ENTRYPOINT ./boot; service rsyslog start; amavisd foreground

amavis/boot

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+#!/bin/bash