diff --git a/apps/vtnweb/src/main/java/org/onosproject/vtnweb/resources/SubnetWebResource.java b/apps/vtnweb/src/main/java/org/onosproject/vtnweb/resources/SubnetWebResource.java
index 779777f944..1d4a5f48bb 100644
--- a/apps/vtnweb/src/main/java/org/onosproject/vtnweb/resources/SubnetWebResource.java
+++ b/apps/vtnweb/src/main/java/org/onosproject/vtnweb/resources/SubnetWebResource.java
@@ -15,6 +15,7 @@
  */
 package org.onosproject.vtnweb.resources;
 
+import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
 import static javax.ws.rs.core.Response.Status.INTERNAL_SERVER_ERROR;
 
@@ -225,6 +226,8 @@ public class SubnetWebResource extends AbstractWebResource {
      */
     public Iterable<Subnet> changeJsonToSub(JsonNode subnetNodes) {
         checkNotNull(subnetNodes, JSON_NOT_NULL);
+        checkArgument(!subnetNodes.get("enable_dhcp").isBoolean(), "enable_dhcp should be boolean");
+        checkArgument(!subnetNodes.get("shared").isBoolean(), "shared should be boolean");
         Map<SubnetId, Subnet> subMap = new HashMap<SubnetId, Subnet>();
         if (!subnetNodes.hasNonNull("id")) {
             return null;
@@ -245,7 +248,7 @@ public class SubnetWebResource extends AbstractWebResource {
             ipVersion = Version.INET;
             break;
         default:
-            ipVersion = null;
+            throw new IllegalArgumentException("ipVersion should be 4 or 6.");
         }
 
         IpPrefix cidr = IpPrefix.valueOf(subnetNodes.get("cidr").asText());
diff --git a/apps/vtnweb/src/main/java/org/onosproject/vtnweb/resources/TenantNetworkWebResource.java b/apps/vtnweb/src/main/java/org/onosproject/vtnweb/resources/TenantNetworkWebResource.java
index 092ea89e7c..65e9589c1d 100644
--- a/apps/vtnweb/src/main/java/org/onosproject/vtnweb/resources/TenantNetworkWebResource.java
+++ b/apps/vtnweb/src/main/java/org/onosproject/vtnweb/resources/TenantNetworkWebResource.java
@@ -16,6 +16,7 @@
 package org.onosproject.vtnweb.resources;
 
 import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Preconditions.checkArgument;
 import static javax.ws.rs.core.Response.Status.INTERNAL_SERVER_ERROR;
 import static javax.ws.rs.core.Response.Status.OK;
 
@@ -268,6 +269,9 @@ public class TenantNetworkWebResource extends AbstractWebResource {
         ConcurrentMap<TenantNetworkId, TenantNetwork> networksMap = Maps
                 .newConcurrentMap();
         if (node != null) {
+            checkArgument(!node.get("admin_state_up").isBoolean(), "admin_state_up should be boolean");
+            checkArgument(!node.get("shared").isBoolean(), "shared should be boolean");
+            checkArgument(!node.get("router:external").isBoolean(), "router:external should be boolean");
             String name = node.get("name").asText();
             boolean adminStateUp = node.get("admin_state_up").asBoolean();
             String state = node.get("status").asText();
diff --git a/apps/vtnweb/src/main/java/org/onosproject/vtnweb/resources/VirtualPortWebResource.java b/apps/vtnweb/src/main/java/org/onosproject/vtnweb/resources/VirtualPortWebResource.java
index 1bcb291034..64266a5661 100644
--- a/apps/vtnweb/src/main/java/org/onosproject/vtnweb/resources/VirtualPortWebResource.java
+++ b/apps/vtnweb/src/main/java/org/onosproject/vtnweb/resources/VirtualPortWebResource.java
@@ -94,7 +94,7 @@ public class VirtualPortWebResource extends AbstractWebResource {
     public Response getportsById(@PathParam("id") String id) {
 
         if (!get(VirtualPortService.class).exists(VirtualPortId.portId(id))) {
-            return ok("the virtualPort does not exists").build();
+            return ok("The virtualPort does not exists").build();
         }
         VirtualPort virtualPort = nullIsNotFound(get(VirtualPortService.class)
                 .getPort(VirtualPortId.portId(id)), VPORT_NOT_FOUND);