diff --git a/tests/components/knx/test_config_flow.py b/tests/components/knx/test_config_flow.py
index 6457d099eb2..a4171e73be2 100644
--- a/tests/components/knx/test_config_flow.py
+++ b/tests/components/knx/test_config_flow.py
@@ -1,9 +1,10 @@
 """Test the KNX config flow."""
 
 from contextlib import contextmanager
-from unittest.mock import MagicMock, Mock, patch
+from unittest.mock import AsyncMock, MagicMock, Mock, patch
 
 import pytest
+from xknx.exceptions import XKNXException
 from xknx.exceptions.exception import CommunicationError, InvalidSecureConfiguration
 from xknx.io import DEFAULT_MCAST_GRP, DEFAULT_MCAST_PORT
 from xknx.io.gateway_scanner import GatewayDescriptor
@@ -60,6 +61,12 @@ FIXTURE_UPLOAD_UUID = "0123456789abcdef0123456789abcdef"
 GATEWAY_INDIVIDUAL_ADDRESS = IndividualAddress("1.0.0")
 
 
+async def _mock_validate_ip_for_invalid_local(ip_address: str) -> str:
+    if ip_address in {"no_local_ip", "asdf"}:
+        raise XKNXException
+    return ip_address
+
+
 @pytest.fixture(name="knx_setup")
 def fixture_knx_setup():
     """Mock KNX entry setup."""
@@ -238,15 +245,19 @@ async def test_routing_setup_advanced(
     assert result["errors"] == {"base": "no_router_discovered"}
 
     # invalid user input
-    result_invalid_input = await hass.config_entries.flow.async_configure(
-        result["flow_id"],
-        {
-            CONF_KNX_MCAST_GRP: "10.1.2.3",  # no valid multicast group
-            CONF_KNX_MCAST_PORT: 3675,
-            CONF_KNX_INDIVIDUAL_ADDRESS: "not_a_valid_address",
-            CONF_KNX_LOCAL_IP: "no_local_ip",
-        },
-    )
+    with patch(
+        "homeassistant.components.knx.config_flow.xknx_validate_ip",
+        new=AsyncMock(side_effect=_mock_validate_ip_for_invalid_local),
+    ):
+        result_invalid_input = await hass.config_entries.flow.async_configure(
+            result["flow_id"],
+            {
+                CONF_KNX_MCAST_GRP: "10.1.2.3",  # no valid multicast group
+                CONF_KNX_MCAST_PORT: 3675,
+                CONF_KNX_INDIVIDUAL_ADDRESS: "not_a_valid_address",
+                CONF_KNX_LOCAL_IP: "no_local_ip",
+            },
+        )
     assert result_invalid_input["type"] is FlowResultType.FORM
     assert result_invalid_input["step_id"] == "routing"
     assert result_invalid_input["errors"] == {
@@ -751,15 +762,19 @@ async def test_tunneling_setup_for_local_ip(
         "base": "no_tunnel_discovered",
     }
     # invalid local ip address
-    result_invalid_local = await hass.config_entries.flow.async_configure(
-        result["flow_id"],
-        {
-            CONF_KNX_TUNNELING_TYPE: CONF_KNX_TUNNELING,
-            CONF_HOST: "192.168.0.2",
-            CONF_PORT: 3675,
-            CONF_KNX_LOCAL_IP: "asdf",
-        },
-    )
+    with patch(
+        "homeassistant.components.knx.config_flow.xknx_validate_ip",
+        new=AsyncMock(side_effect=_mock_validate_ip_for_invalid_local),
+    ):
+        result_invalid_local = await hass.config_entries.flow.async_configure(
+            result["flow_id"],
+            {
+                CONF_KNX_TUNNELING_TYPE: CONF_KNX_TUNNELING,
+                CONF_HOST: "192.168.0.2",
+                CONF_PORT: 3675,
+                CONF_KNX_LOCAL_IP: "asdf",
+            },
+        )
     assert result_invalid_local["type"] is FlowResultType.FORM
     assert result_invalid_local["step_id"] == "manual_tunnel"
     assert result_invalid_local["errors"] == {