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stretch/Dockerfile

@@ -8,11 +8,7 @@ RUN set -ex; \
     apt-get install -y exim4-daemon-light; \
     apt-get clean
 
-# Copy the main script.
 COPY docker-entrypoint.sh /usr/local/bin/docker-entrypoint.sh
-
-# We expose exim on port 25.
 EXPOSE 25/tcp
-
 ENTRYPOINT [ "docker-entrypoint.sh" ]
 CMD [ "exim", "-bdf", "-v", "-q30m" ]

stretch/docker-entrypoint.sh

@@ -10,7 +10,7 @@ DC_EXIMCONFIG_CONFIGTYPE="internet"
 # in case port 25 is accidentally exposed to the public internet.
 DC_RELAY_NETS="10.0.0.0/8;172.16.0.0/12;192.168.0.0/16"
 
-# Set smarthost.
+# If RELAY_HOST has been set then switch to smart host configuration.
 if [ "x$RELAY_HOST" != "x" ]; then
     DC_EXIMCONFIG_CONFIGTYPE="satellite"
     DC_SMARTHOST="$RELAY_HOST::${RELAY_PORT:-25}"