diff --git a/Dockerfile b/Dockerfile
index 21ac6bc66e7e674b8dce10387c2df0eaf6cdaaee..51380b268c4bee97551ddf4a131bc0b871c6cf28 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,7 +2,8 @@ FROM debian:stretch-slim
 ENV DEBIAN_FRONTEND noninteractive
 RUN apt-get update && \
     apt-get install -y unbound unbound-host dnsutils dma bsd-mailx && \
-    rm -rf /tmp/* /var/tmp/* /var/lib/apt/lists/* /var/cache/apt/archives/*
+    rm -rf /tmp/* /var/tmp/* /var/lib/apt/lists/* /var/cache/apt/archives/* &&
+    unbound-checkconf
 COPY entrypoint.sh /entrypoint.sh
 ENTRYPOINT ["/entrypoint.sh"]
 CMD ["/bin/bash", "--login"]