diff --git a/front_auditd.sh b/front_auditd.sh
index 124057b..0f99332 100644
--- a/front_auditd.sh
+++ b/front_auditd.sh
@@ -97,9 +97,9 @@ yad --plug=$_NUMBER --tabnum=2 --form \
 	--image=security-medium \
 	--scroll \
 	--field=$"Tcp listen port::LBL" "!" \
-	  --field=$"${_tag1}(Value) Tcp listen port${_tag2}::NUM" "${tcp_listen_port:--}!1..65535!1" \
+	  --field=$"${_tag1}(Value) Tcp listen port${_tag2}::NUM" "${tcp_listen_port:-0}!0..65535!1" \
 	--field=$"Tcp max per addr::LBL" "!" \
-	  --field=$"${_tag1}(Value) Tcp max per addr${_tag2}::NUM" "${tcp_max_per_addr_port:--}!1..65535!1" \
+	  --field=$"${_tag1}(Value) Tcp max per addr${_tag2}::NUM" "${tcp_max_per_addr_port:-0}!0..65535!1" \
 	--field=$"Systemd firewalling params:LBL" "!" \
 	  --field=$"${_tag1}(Value) Allowed IPs${_tag2}::TXT" "$(if [ -z "$systemd_allowed_ips" ]; then echo "-"; else echo -e "${systemd_allowed_ip_list// /\\n}"; fi)" \
 	  --field=$"${_tag1}(Value) Denied IPs${_tag2}::TXT" "$(if [ -z "$systemd_allowed_ips" ]; then echo "-"; else echo -e "${systemd_denied_ip_list// /\\n}"; fi)" &>"$_temp_file2" &