diff --git a/blockauth b/blockauth
index 445ddae..9e743bc 100755
--- a/blockauth
+++ b/blockauth
@@ -116,8 +116,8 @@ function run_iptables() {
   iptables -F
   ipset destroy blockauth 2> /dev/null
   ipset create blockauth hash:ip
-  iptables -A INPUT -p tcp -m multiport --sports ${1} -m set --match-set blockauth src -j DROP
-  iptables -A OUTPUT -p tcp -m multiport --sports ${1} -m set --match-set blockauth src -j DROP
+  iptables -I INPUT -p tcp -m multiport --dports ${1} -m set --match-set blockauth src -j DROP
+  iptables -I OUTPUT -p tcp -m multiport --dports ${1} -m set --match-set blockauth src -j DROP
 }
 
 # Reset initial configuration