diff --git a/twamp/files/etc/firewall.twamp b/twamp/files/etc/firewall.twamp
index db5532d2f..0d93c5c0b 100644
--- a/twamp/files/etc/firewall.twamp
+++ b/twamp/files/etc/firewall.twamp
@@ -29,8 +29,8 @@ function configure_firewall()
 
 function delete_rule()
 {
-        while iptables -w 1 -L zone_${1}_input --line-numbers 2>/dev/null | grep "TWAMP reflector port"; do
-		rule_num="$(iptables -w 1 -L zone_${1}_input --line-numbers | grep "TWAMP reflector port" | head -1|awk '{print $1}')"
+        while iptables -w 1 -nL zone_${1}_input --line-numbers 2>/dev/null | grep "TWAMP reflector port"; do
+		rule_num="$(iptables -w 1 -nL zone_${1}_input --line-numbers | grep "TWAMP reflector port" | head -1|awk '{print $1}')"
 		if [ -n "${rule_num}" ]; then
 			iptables -w 1 -D zone_${1}_input ${rule_num};
 		fi