diff --git a/python/neutron-understack/neutron_understack/tests/test_neutron_understack_mech.py b/python/neutron-understack/neutron_understack/tests/test_neutron_understack_mech.py
index 017277242..3cea83b58 100644
--- a/python/neutron-understack/neutron_understack/tests/test_neutron_understack_mech.py
+++ b/python/neutron-understack/neutron_understack/tests/test_neutron_understack_mech.py
@@ -1,6 +1,7 @@
 from dataclasses import dataclass
 
 import pytest
+from neutron_lib.api.definitions import portbindings
 from neutron_lib.plugins.ml2 import api
 from oslo_config import cfg
 
@@ -13,6 +14,22 @@ def test_with_simple_port(self, understack_driver, port_context):
 
         understack_driver.undersync.sync_devices.assert_called_once()
 
+    def test_skips_non_baremetal_port(self, understack_driver, port_context):
+        port_context.current[portbindings.VNIC_TYPE] = portbindings.VNIC_NORMAL
+
+        understack_driver.update_port_postcommit(port_context)
+
+        understack_driver.undersync.sync_devices.assert_not_called()
+
+
+class TestDeletePortPostCommit:
+    def test_skips_non_baremetal_port(self, understack_driver, port_context):
+        port_context.current[portbindings.VNIC_TYPE] = portbindings.VNIC_NORMAL
+
+        understack_driver.delete_port_postcommit(port_context)
+
+        understack_driver.undersync.sync_devices.assert_not_called()
+
 
 @pytest.mark.usefixtures("_ironic_baremetal_port_physical_network")
 class TestBindPort:
@@ -94,6 +111,31 @@ def test_with_no_trunk(
             next_segments_to_bind=[vlan_network_segment],
         )
 
+    def test_refuses_unsupported_vnic_type(
+        self, mocker, port_context, understack_driver
+    ):
+        port_context.current[portbindings.VNIC_TYPE] = portbindings.VNIC_DIRECT
+        mocker.patch.object(port_context, "continue_binding")
+        port_context._prepare_to_bind(port_context.network.network_segments)
+
+        understack_driver.bind_port(port_context)
+
+        port_context.continue_binding.assert_not_called()
+
+    @pytest.mark.usefixtures("_ironic_baremetal_port_physical_network")
+    def test_does_not_bind_when_physical_network_not_found(
+        self, mocker, port_context, understack_driver
+    ):
+        understack_driver.ironic_client.baremetal_port_physical_network.return_value = (
+            None
+        )
+        mocker.patch.object(port_context, "continue_binding")
+        port_context._prepare_to_bind(port_context.network.network_segments)
+
+        understack_driver.bind_port(port_context)
+
+        port_context.continue_binding.assert_not_called()
+
     @pytest.mark.parametrize("port_dict", [{"trunk": True}], indirect=True)
     def test_with_trunk_details(
         self, mocker, understack_driver, port_context, understack_trunk_driver
diff --git a/python/neutron-understack/neutron_understack/tests/test_undersync_mech.py b/python/neutron-understack/neutron_understack/tests/test_undersync_mech.py
index 42a229a3a..bda708a1f 100644
--- a/python/neutron-understack/neutron_understack/tests/test_undersync_mech.py
+++ b/python/neutron-understack/neutron_understack/tests/test_undersync_mech.py
@@ -92,13 +92,14 @@ def test_skips_unsupported_vnic_type(self, driver, vlan_segment):
 
         ctx.set_binding.assert_not_called()
 
-    def test_normal_vnic_type_is_supported(self, driver, vlan_segment):
-        seg = vlan_segment()
-        ctx = _make_context(vnic_type=portbindings.VNIC_NORMAL, segments=[seg])
+    def test_normal_vnic_type_is_not_supported(self, driver, vlan_segment):
+        ctx = _make_context(
+            vnic_type=portbindings.VNIC_NORMAL, segments=[vlan_segment()]
+        )
 
         driver.bind_port(ctx)
 
-        ctx.set_binding.assert_called_once()
+        ctx.set_binding.assert_not_called()
 
     def test_binds_vlan_when_preceded_by_vxlan(
         self, driver, vxlan_segment, vlan_segment
@@ -121,3 +122,22 @@ def test_empty_segments_to_bind(self, driver):
         driver.bind_port(ctx)
 
         ctx.set_binding.assert_not_called()
+
+    def test_skips_direct_vnic_type(self, driver, vlan_segment):
+        ctx = _make_context(
+            vnic_type=portbindings.VNIC_DIRECT, segments=[vlan_segment()]
+        )
+
+        driver.bind_port(ctx)
+
+        ctx.set_binding.assert_not_called()
+
+    def test_logs_warning_when_no_vlan_segment_found(
+        self, driver, vxlan_segment, caplog
+    ):
+        ctx = _make_context(segments=[vxlan_segment()])
+
+        driver.bind_port(ctx)
+
+        assert "no VLAN segment found" in caplog.text
+        ctx.set_binding.assert_not_called()
diff --git a/python/neutron-understack/neutron_understack/undersync_mech.py b/python/neutron-understack/neutron_understack/undersync_mech.py
index f986661ff..97e649c7c 100644
--- a/python/neutron-understack/neutron_understack/undersync_mech.py
+++ b/python/neutron-understack/neutron_understack/undersync_mech.py
@@ -9,7 +9,7 @@
 
 LOG = logging.getLogger(__name__)
 
-SUPPORTED_VNIC_TYPES = [portbindings.VNIC_BAREMETAL, portbindings.VNIC_NORMAL]
+SUPPORTED_VNIC_TYPES = [portbindings.VNIC_BAREMETAL]
 
 
 class UndersyncDriver(MechanismDriver):