diff --git a/target/start-mailserver.sh b/target/start-mailserver.sh
index 78e42cc4..cfec849d 100644
--- a/target/start-mailserver.sh
+++ b/target/start-mailserver.sh
@@ -28,8 +28,8 @@ DEFAULT_VARS["DOVECOT_BASE"]="${DOVECOT_BASE:="${LDAP_SEARCH_BASE}"}"
 DEFAULT_VARS["DOVECOT_DN"]="${DOVECOT_DN:="${LDAP_BIND_DN}"}"
 DEFAULT_VARS["DOVECOT_DNPASS"]="${DOVECOT_DNPASS:="${LDAP_BIND_PW}"}"
 DEFAULT_VARS["DOVECOT_HOSTS"]="${DOVECOT_HOSTS:="${LDAP_SERVER_HOST}"}"
-DEFAULT_VARS["DOVECOT_PASS_FILTER"]="${DOVECOT_PASS_FILTER}="${LDAP_QUERY_FILTER}"}"
-DEFAULT_VARS["DOVECOT_USER_FILTER"]="${DOVECOT_USER_FILTER}="${LDAP_QUERY_FILTER}"}"
+DEFAULT_VARS["DOVECOT_PASS_FILTER"]="${DOVECOT_PASS_FILTER:="${LDAP_QUERY_FILTER}"}"
+DEFAULT_VARS["DOVECOT_USER_FILTER"]="${DOVECOT_USER_FILTER:="${LDAP_QUERY_FILTER}"}"
 
 ##########################################################################
 # << DEFAULT VARS