diff --git a/Dockerfile b/Dockerfile
index 0c021ea0..06737c76 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -10,6 +10,9 @@ RUN apt-get update -q --fix-missing && \
   apt-get -y upgrade && \
   apt-get -y install postfix
 RUN apt-get update -q --fix-missing && \
+  apt-get -y upgrade && \
+  apt-get -y install postfix
+RUN DEBIAN_FRONTEND=noninteractive apt-get update -q --fix-missing && \
   apt-get -y upgrade && \
   apt-get -y install --no-install-recommends \
     amavisd-new \