diff --git a/Dockerfile b/Dockerfile
index f06887e..c5295de 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,7 +2,8 @@ FROM nginx:alpine
 
 ENV HTPASSWD='foo:$apr1$odHl5EJN$KbxMfo86Qdve2FH4owePn.' \
     FORWARD_PORT=80 \
-    FORWARD_HOST=web
+    FORWARD_HOST=web \
+    DNS_RESOLVER=
 
 WORKDIR /opt
 
diff --git a/launch.sh b/launch.sh
index f5aba9e..f1a9050 100755
--- a/launch.sh
+++ b/launch.sh
@@ -4,4 +4,8 @@ rm /etc/nginx/conf.d/default.conf || :
 envsubst < auth.conf > /etc/nginx/conf.d/auth.conf
 envsubst < auth.htpasswd > /etc/nginx/auth.htpasswd
 
+if [ -n "${DNS_RESOLVER}" ]; then
+  echo "resolver ${DNS_RESOLVER};" >> /etc/nginx/conf.d/auth.conf
+fi
+
 nginx -g "daemon off;"