vxlan: T3700: can not specify both "external" and "VNI"

2 files changed, 9 insertions, 0 deletions

diff --git a/smoketest/scripts/cli/test_interfaces_vxlan.py b/smoketest/scripts/cli/test_interfaces_vxlan.py
index 17874af89..9278adadd 100755
--- a/smoketest/scripts/cli/test_interfaces_vxlan.py
+++ b/smoketest/scripts/cli/test_interfaces_vxlan.py
@@ -95,6 +95,12 @@ class VXLANInterfaceTest(BasicInterfaceTest.TestCase):
         self.cli_set(self._base_path + [interface, 'external'])
         self.cli_set(self._base_path + [interface, 'source-address', source_address])
 
+        # Both 'VNI' and 'external' can not be specified at the same time.
+        self.cli_set(self._base_path + [interface, 'vni', '111'])
+        with self.assertRaises(ConfigSessionError):
+            self.cli_commit()
+        self.cli_delete(self._base_path + [interface, 'vni'])
+
         # Now add some more interfaces - this must fail and a CLI error needs
         # to be generated as Linux can only handle one VXLAN tunnel when using
         # external mode.
diff --git a/src/conf_mode/interfaces-vxlan.py b/src/conf_mode/interfaces-vxlan.py
index b197d08a6..95d982f38 100755
--- a/src/conf_mode/interfaces-vxlan.py
+++ b/src/conf_mode/interfaces-vxlan.py
@@ -81,6 +81,9 @@ def verify(vxlan):
         raise ConfigError(
             'Must either configure VXLAN "vni" or use "external" CLI option!')
 
+    if {'external', 'vni'} <= set(vxlan):
+        raise ConfigError('Can not specify both "external" and "VNI"!')
+
     if {'external', 'other_tunnels'} <= set(vxlan):
         other_tunnels = ', '.join(vxlan['other_tunnels'])
         raise ConfigError(f'Only one VXLAN tunnel is supported when "external" '\