diff --git a/unittest/error-vxlan1.yaml b/unittest/error-vxlan1.yaml
new file mode 100644
index 0000000..f126395
--- /dev/null
+++ b/unittest/error-vxlan1.yaml
@@ -0,0 +1,16 @@
+test:
+  description: "A VXLAN source and destination must be the same address family"
+  errors:
+    expected:
+     - "vxlan_tunnel .* local and remote are not the same address family"
+    count: 1
+---
+vxlan_tunnels:
+  vxlan_tunnel0:
+    local: 192.0.2.1
+    remote: 2001:db8::1
+    vni: 100
+
+interfaces:
+  vxlan_tunnel0:
+    description: "My little tunnel"
diff --git a/unittest/error-vxlan2.yaml b/unittest/error-vxlan2.yaml
new file mode 100644
index 0000000..4a6a7a1
--- /dev/null
+++ b/unittest/error-vxlan2.yaml
@@ -0,0 +1,24 @@
+test:
+  description: "VXLAN VNIs must be unique"
+  errors:
+    expected:
+     - "vxlan_tunnel .* VNI .* is not unique"
+    count: 2
+---
+vxlan_tunnels:
+  vxlan_tunnel0:
+    local: 192.0.2.1
+    remote: 192.0.2.2
+    vni: 100
+
+  vxlan_tunnel1:
+    local: 2001:db8::1
+    remote: 2001:db8::2
+    vni: 100
+
+interfaces:
+  vxlan_tunnel0:
+    description: "This tunnel has the same VNI as vxlan_tunnel1"
+
+  vxlan_tunnel1:
+    description: "This tunnel has the same VNI as vxlan_tunnel0"
diff --git a/validator/vxlan_tunnel.py b/validator/vxlan_tunnel.py
index dae55f5..e614bdc 100644
--- a/validator/vxlan_tunnel.py
+++ b/validator/vxlan_tunnel.py
@@ -13,6 +13,7 @@
 #
 import logging
 import validator.interface as interface
+import ipaddress
 
 class NullHandler(logging.Handler):
     def emit(self, record):
@@ -54,4 +55,14 @@ def validate_vxlan_tunnels(yaml):
 
     for ifname, iface in yaml['vxlan_tunnels'].items():
         logger.debug("vxlan_tunnel %s: %s" % (ifname, iface))
+        vni = iface['vni']
+        if not vni_unique(yaml, vni):
+            msgs.append("vxlan_tunnel %s VNI %d is not unique" % (ifname, vni))
+            result = False
+        local = ipaddress.ip_address(iface['local'])
+        remote = ipaddress.ip_address(iface['remote'])
+        if local.version != remote.version:
+            msgs.append("vxlan_tunnel %s local and remote are not the same address family" % (ifname))
+            result = False
+
     return result, msgs