diff --git a/neutron/agent/l3/router_info.py b/neutron/agent/l3/router_info.py
index ac44a4b13c5..a685114cd4b 100644
--- a/neutron/agent/l3/router_info.py
+++ b/neutron/agent/l3/router_info.py
@@ -883,9 +883,8 @@ class RouterInfo(BaseRouterInfo):
 
     def _prevent_snat_for_internal_traffic_rule(self, interface_name):
         return (
-            'POSTROUTING', '! -i %(interface_name)s '
-                           '! -o %(interface_name)s -m conntrack ! '
-                           '--ctstate DNAT -j ACCEPT' %
+            'POSTROUTING', '! -o %(interface_name)s -m conntrack '
+                           '! --ctstate DNAT -j ACCEPT' %
                            {'interface_name': interface_name})
 
     def external_gateway_nat_fip_rules(self, ex_gw_ip, interface_name):