diff --git a/comanage-registry-slapd-base/Dockerfile b/comanage-registry-slapd-base/Dockerfile
index 89e7f17..10d1209 100644
--- a/comanage-registry-slapd-base/Dockerfile
+++ b/comanage-registry-slapd-base/Dockerfile
@@ -20,6 +20,7 @@ FROM debian:jessie
 
 RUN apt-get update \
     && DEBIAN_FRONTEND=noninteractive apt-get install --no-install-recommends -y \
+        ca-certificates \
         ldap-utils \
         slapd \
     && cp -a /var/lib/ldap /var/lib/ldap.dist \