[Postfix] Finally here: MX based transport map routing; Sorry it took years, Patrik

[Web] Small fixes

data/Dockerfiles/postfix/postfix.sh

@@ -337,6 +337,19 @@ query = SELECT goto FROM alias
       AND alias_domain.active='1'
 EOF
 
+# MX based routing
+cat <<EOF > /opt/postfix/conf/sql/mysql_mbr_access_maps.cf
+# Autogenerated by mailcow
+user = ${DBUSER}
+password = ${DBPASS}
+hosts = unix:/var/run/mysqld/mysqld.sock
+dbname = ${DBNAME}
+query = SELECT CONCAT('FILTER smtp_via_transport_maps:', nexthop) as transport FROM transports
+  WHERE '%s' REGEXP destination
+    AND active='1'
+    AND is_mx_based='1';
+EOF
+
 # Reject sasl usernames with smtp disabled
 cat <<EOF > /opt/postfix/conf/sql/mysql_sasl_access_maps.cf
 # Autogenerated by mailcow