diff --git a/build/Dockerfile.ubuntu b/build/Dockerfile.ubuntu
index 2470947..3867f76 100644
--- a/build/Dockerfile.ubuntu
+++ b/build/Dockerfile.ubuntu
@@ -25,7 +25,7 @@ RUN apt remove -y nano* exim*; \
     && bash -c "echo \"postfix postfix/main_mailer_type string 'Internet Site'\" | debconf-set-selections" \
     && apt install -y \
         ca-certificates \
-        git wget bind9-host acl dbconfig-no-thanks \
+        git wget bind9-host acl dbconfig-no-thanks at \
         rsyslog \
         nginx \
         mariadb-server mariadb-client postfix-mysql dovecot-mysql \