diff --git a/tools/genenv b/tools/genenv
index cd2a3bd00c..efb5f51312 100755
--- a/tools/genenv
+++ b/tools/genenv
@@ -112,3 +112,6 @@ RABBITMQ_USER=$RABBIT_USER
 RABBIT_PASSWORD=$RABBIT_PASSWORD
 RABBIT_USERID=$RABBIT_USER
 EOF
+echo Please customize your FLAT_INTERFACE to a different network then your
+echo main network. The FLAT_INTERFACE is used for inter-VM communication.
+echo the FLAT_INTERFACE should not have an IP address assigned.