diff --git a/Dockerfile b/Dockerfile
index 5a64c720..84fc658f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,6 +6,7 @@ RUN apk update -f \
   coreutils \
   curl \
   socat \
+  bind-tools \
   && rm -rf /var/cache/apk/*
 
 ENV LE_CONFIG_HOME /acme.sh