diff --git a/build-scripts/postfix-install.sh b/build-scripts/postfix-install.sh
index 2daf030..67c10bc 100644
--- a/build-scripts/postfix-install.sh
+++ b/build-scripts/postfix-install.sh
@@ -8,7 +8,7 @@ fi
 do_alpine() {
     apk update
     apk add --upgrade cyrus-sasl cyrus-sasl-static cyrus-sasl-digestmd5 cyrus-sasl-crammd5 cyrus-sasl-login cyrus-sasl-ntlm libsasl
-    apk add postfix postfix-pcre
+    apk add postfix postfix-pcre postfix-ldap
     apk add opendkim
     apk add --upgrade ca-certificates tzdata supervisor rsyslog musl musl-utils bash opendkim-utils libcurl jsoncpp lmdb logrotate netcat-openbsd
 }
@@ -23,7 +23,7 @@ do_ubuntu() {
     echo "Europe/Berlin" > /etc/timezone
     apt-get update -y -q
     apt-get install -y libsasl2-modules sasl2-bin
-    apt-get install -y postfix postfix-pcre
+    apt-get install -y postfix postfix-pcre postfix-ldap
     apt-get install -y opendkim
     apt-get install -y ca-certificates tzdata supervisor rsyslog bash opendkim-tools curl libcurl4 libjsoncpp25 sasl2-bin postfix-lmdb procps logrotate cron net-tools ${RELEASE_SPECIFIC_PACKAGES}
     apt-get clean