diff --git a/.gitignore b/.gitignore
index 37cbdd4e..324b2201 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,4 @@ __pycache__
 /admin/include
 pip-selfcheck.json
 /data
+/docker-compose.mac.yml
diff --git a/docker-compose.yml b/docker-compose.yml
index 9a3a9cb0..bc99b5e9 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -47,6 +47,7 @@ services:
     volumes:
       - /freeposte/freeposte:/data
       - /freeposte/certs:/certs
+      - /freeposte/overrides:/overrides
 
   milter:
     build: rmilter
diff --git a/postfix/conf/main.cf b/postfix/conf/main.cf
index 97ac8b13..6cbeca97 100644
--- a/postfix/conf/main.cf
+++ b/postfix/conf/main.cf
@@ -48,4 +48,8 @@ lmtp_host_lookup = native
 smtpd_milters = inet:milter:9900
 milter_protocol = 6
 milter_mail_macros = i {mail_addr} {client_addr} {client_name} {auth_authen}
-milter_default_action = tempfail
\ No newline at end of file
+milter_default_action = tempfail
+
+###############
+# Extra Settings
+###############
diff --git a/postfix/start.sh b/postfix/start.sh
index 7891be74..c0931433 100755
--- a/postfix/start.sh
+++ b/postfix/start.sh
@@ -5,6 +5,28 @@ for VARIABLE in `env | cut -f1 -d=`; do
   sed -i "s={{ $VARIABLE }}=${!VARIABLE}=g" /etc/postfix/*.cf
 done
 
+# Override Postfix configuration
+if [ -f /overrides/postfix.cf ]; then
+  while read line; do
+    postconf -e "$line"
+  done < /overrides/postfix.cf
+  echo "Loaded '/overrides/postfix.cf'"
+else
+  echo "No extra postfix settings loaded because optional '/overrides/postfix.cf' not provided."
+fi
+
+# Include table-map files
+if ls -A /overrides/*.map 1> /dev/null 2>&1; then
+  cp /overrides/*.map /etc/postfix/
+  postmap /etc/postfix/*.map
+  rm /etc/postfix/*.map
+  chown root:root /etc/postfix/*.db
+  chmod 0600 /etc/postfix/*.db
+  echo "Loaded 'map files'"
+else
+  echo "No extra map files loaded because optional '/overrides/*.map' not provided."
+fi
+
 # Actually run Postfix
 rm -f /var/run/rsyslogd.pid
 /usr/lib/postfix/master &