diff --git a/Dockerfile b/Dockerfile
index 46e2abc3..14eca30f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -195,8 +195,10 @@ COPY target/opendmarc/ignore.hosts /etc/opendmarc/ignore.hosts
 # --- postfix-mta-sts-daemon -----------------------
 # --------------------------------------------------
 COPY target/mta-sts-daemon/mta-sts-daemon.yml /etc/mta-sts-daemon.yml
-RUN mkdir /var/run/mta-sts
-RUN chown -R _mta-sts:root /var/run/mta-sts
+RUN << EOF
+  mkdir /var/run/mta-sts
+  chown -R _mta-sts:root /var/run/mta-sts
+EOF
 
 # --------------------------------------------------
 # --- Fetchmail, Getmail, Postfix & Let'sEncrypt ---