diff --git a/docker/postfix/Dockerfile b/docker/postfix/Dockerfile
index db8b672e..f9e3919a 100644
--- a/docker/postfix/Dockerfile
+++ b/docker/postfix/Dockerfile
@@ -1,51 +1,51 @@
 FROM almalinux:8
 
 LABEL maintainer="contact@apheleia-it.ch"
 LABEL dist=centos8
 LABEL tier=${TIER}
 
 ENV DISTRO=centos8
 # ENV LANG=en_US.utf8
 # ENV LC_ALL=en_US.utf8
-# ENV APP_DOMAIN
-# ENV LMTP_DESTINATION
-# ENV DB_HOST
-# ENV DB_USERNAME
-# ENV DB_PASSWORD
-# ENV DB_DATABASE
 
 # Add EPEL.
 RUN dnf -y install dnf-plugin-config-manager && \
     dnf config-manager --set-enabled powertools && \
     dnf -y install \
     epel-release \
     python3 \
     python3-requests \
     postfix \
     postfix-mysql \
     cyrus-sasl \
     cyrus-sasl-plain \
     procps-ng \
     iputils \
     bind-utils \
     tcpdump \
     vim-enhanced && \
     dnf clean all
 RUN rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-8
 
 RUN sed -i -r -e 's/^SELINUX=.*$/SELINUX=permissive/g' /etc/selinux/config 2>/dev/null || :
 
 WORKDIR /root/
 
 COPY /rootfs /
 
 VOLUME [ "/var/spool/postfix" ]
 VOLUME [ "/var/lib/postfix" ]
 
 ENV SERVICES_PORT=8000
 # ENV APP_SERVICES_DOMAIN
 # ENV APP_DOMAIN
+# ENV LMTP_DESTINATION
+ENV MYNETWORKS="172.0.0.0/8"
+# ENV DB_HOST
+# ENV DB_USERNAME
+# ENV DB_PASSWORD
+# ENV DB_DATABASE
 
 CMD ["/init.sh"]
 
 EXPOSE 10025/tcp 10587/tcp
diff --git a/docker/postfix/rootfs/init.sh b/docker/postfix/rootfs/init.sh
index ce4ed4c0..7ac7a968 100755
--- a/docker/postfix/rootfs/init.sh
+++ b/docker/postfix/rootfs/init.sh
@@ -1,47 +1,47 @@
 #!/bin/bash
 
 set -e
 
 cat ${SSL_CERTIFICATE} ${SSL_CERTIFICATE_FULLCHAIN} ${SSL_CERTIFICATE_KEY} > /etc/pki/tls/private/postfix.pem
 chown postfix:mail /etc/pki/tls/private/postfix.pem
 chmod 655 /etc/pki/tls/private/postfix.pem
 
 sed -i -r \
     -e "s|APP_SERVICES_DOMAIN|$APP_SERVICES_DOMAIN|g" \
     -e "s|SERVICES_PORT|$SERVICES_PORT|g" \
     /etc/saslauthd.conf
 
 /usr/sbin/saslauthd -m /run/saslauthd -a httpform -d &
 
 # If host mounting /var/spool/postfix, we need to delete old pid file before
 # starting services
 rm -f /var/spool/postfix/pid/master.pid
 
 /usr/libexec/postfix/aliasesdb
 /usr/libexec/postfix/chroot-update
 
 sed -i -r \
     -e "s|LMTP_DESTINATION|$LMTP_DESTINATION|g" \
     /etc/postfix/main.cf
 
 sed -i -r \
     -e "s|APP_DOMAIN|$APP_DOMAIN|g" \
-    -e "s|MYNETWORKS|172.18.0.0/24|g" \
+    -e "s|MYNETWORKS|$MYNETWORKS|g" \
     /etc/postfix/main.cf
 
 sed -i -r \
     -e "s|SERVICES_HOST|http://$APP_SERVICES_DOMAIN:$SERVICES_PORT|g" \
     /usr/libexec/postfix/kolab_policy*
 
 sed -i -r \
     -e "s|DB_HOST|$DB_HOST|g" \
     -e "s|DB_USERNAME|$DB_USERNAME|g" \
     -e "s|DB_PASSWORD|$DB_PASSWORD|g" \
     -e "s|DB_DATABASE|$DB_DATABASE|g" \
     /etc/postfix/sql/*
 
 # echo "/$APP_DOMAIN/              lmtp:$LMTP_DESTINATION" >> /etc/postfix/transport
 # postmap /etc/postfix/transport
 
 /usr/sbin/postfix check
 exec /usr/sbin/postfix -c /etc/postfix start-fg