diff --git a/target/start-mailserver.sh b/target/start-mailserver.sh
index ed3ba9ba..3939a134 100644
--- a/target/start-mailserver.sh
+++ b/target/start-mailserver.sh
@@ -7,18 +7,18 @@
 # Example: DEFAULT_VARS["KEY"]="VALUE"
 ##########################################################################
 declare -A DEFAULT_VARS
-DEFAULT_VARS["ENABLE_CLAMAV"]=${ENABLE_CLAMAV:-0}
-DEFAULT_VARS["ENABLE_SPAMASSASSIN"]=${ENABLE_SPAMASSASSIN:-0}
-DEFAULT_VARS["ENABLE_POP3"]=${ENABLE_POP3:-0}
-DEFAULT_VARS["ENABLE_FAIL2BAN"]=${ENABLE_FAIL2BAN:-0}
-DEFAULT_VARS["ENABLE_MANAGESIEVE"]=${ENABLE_MANAGESIEVE:-0}
-DEFAULT_VARS["ENABLE_FETCHMAIL"]=${ENABLE_FETCHMAIL:-0}
-DEFAULT_VARS["ENABLE_LDAP"]=${ENABLE_LDAP:-0}
-DEFAULT_VARS["ENABLE_SASLAUTHD"]=${ENABLE_SASLAUTHD:-0}
-DEFAULT_VARS["ONE_DIR"]=${ONE_DIR:-0}
-DEFAULT_VARS["SMTP_ONLY"]=${SMTP_ONLY:-0}
-DEFAULT_VARS["VIRUSMAILS_DELETE_DELAY"]=${VIRUSMAILS_DELETE_DELAY:-7}
-DEFAULT_VARS["DMS_DEBUG"]=${DMS_DEBUG:-0}
+DEFAULT_VARS["ENABLE_CLAMAV"]=${ENABLE_CLAMAV:=0}
+DEFAULT_VARS["ENABLE_SPAMASSASSIN"]=${ENABLE_SPAMASSASSIN:=0}
+DEFAULT_VARS["ENABLE_POP3"]=${ENABLE_POP3:=0}
+DEFAULT_VARS["ENABLE_FAIL2BAN"]=${ENABLE_FAIL2BAN:=0}
+DEFAULT_VARS["ENABLE_MANAGESIEVE"]=${ENABLE_MANAGESIEVE:=0}
+DEFAULT_VARS["ENABLE_FETCHMAIL"]=${ENABLE_FETCHMAIL:=0}
+DEFAULT_VARS["ENABLE_LDAP"]=${ENABLE_LDAP:=0}
+DEFAULT_VARS["ENABLE_SASLAUTHD"]=${ENABLE_SASLAUTHD:=0}
+DEFAULT_VARS["ONE_DIR"]=${ONE_DIR:=0}
+DEFAULT_VARS["SMTP_ONLY"]=${SMTP_ONLY:=0}
+DEFAULT_VARS["VIRUSMAILS_DELETE_DELAY"]=${VIRUSMAILS_DELETE_DELAY:=7}
+DEFAULT_VARS["DMS_DEBUG"]=${DMS_DEBUG:=0}
 ##########################################################################
 # << DEFAULT VARS
 ##########################################################################