diff --git a/quantum/agent/linux/ip_lib.py b/quantum/agent/linux/ip_lib.py
index 4065b44fff..31337087e6 100644
--- a/quantum/agent/linux/ip_lib.py
+++ b/quantum/agent/linux/ip_lib.py
@@ -297,7 +297,7 @@ class IpRouteCommand(IpDeviceCommandBase):
     COMMAND = 'route'
 
     def add_gateway(self, gateway, metric=None):
-        args = ['add', 'default', 'via', gateway]
+        args = ['replace', 'default', 'via', gateway]
         if metric:
             args += ['metric', metric]
         args += ['dev', self.name]
diff --git a/quantum/tests/unit/test_linux_ip_lib.py b/quantum/tests/unit/test_linux_ip_lib.py
index f4a67dec13..cc54ff23cd 100644
--- a/quantum/tests/unit/test_linux_ip_lib.py
+++ b/quantum/tests/unit/test_linux_ip_lib.py
@@ -548,7 +548,7 @@ class TestIpRouteCommand(TestIPCmdBase):
         metric = 100
         self.route_cmd.add_gateway(gateway, metric)
         self._assert_sudo([],
-                          ('add', 'default', 'via', gateway,
+                          ('replace', 'default', 'via', gateway,
                            'metric', metric,
                            'dev', self.parent.name))