diff --git a/server/src/com/cloud/configuration/ConfigurationManagerImpl.java b/server/src/com/cloud/configuration/ConfigurationManagerImpl.java
index 2089f82dfe9..8d8b12680ba 100755
--- a/server/src/com/cloud/configuration/ConfigurationManagerImpl.java
+++ b/server/src/com/cloud/configuration/ConfigurationManagerImpl.java
@@ -3120,10 +3120,10 @@ public class ConfigurationManagerImpl extends ManagerBase implements Configurati
             }
         }
 
-        // Check if a guest VLAN is using the same tag
+        // Check if the vlan is being used 
         if (_zoneDao.findVnet(zoneId, physicalNetworkId, vlanId).size() > 0) {
             throw new InvalidParameterValueException("The VLAN tag " + vlanId
-                    + " is already being used for the guest network in zone " + zone.getName());
+                    + " is already being used for dynamic vlan allocation for the guest network in zone " + zone.getName());
         }
 
         String ipRange = null;
diff --git a/server/src/com/cloud/network/NetworkManagerImpl.java b/server/src/com/cloud/network/NetworkManagerImpl.java
index 938d9b1e646..dac6a3a42e7 100755
--- a/server/src/com/cloud/network/NetworkManagerImpl.java
+++ b/server/src/com/cloud/network/NetworkManagerImpl.java
@@ -2467,7 +2467,13 @@ public class NetworkManagerImpl extends ManagerBase implements NetworkManager, L
             }
         }
 
-        if (vlanId != null) {
+        if (vlanSpecified) {
+            //don't allow to specify vlan tag used by physical network for dynamic vlan allocation
+            if (_dcDao.findVnet(zoneId, pNtwk.getId(), vlanId).size() > 0) {
+                throw new InvalidParameterValueException("The VLAN tag " + vlanId
+                        + " is already being used for dynamic vlan allocation for the guest network in zone " + zone.getName());
+            }
+            
             String uri = "vlan://" + vlanId;
             // For Isolated networks, don't allow to create network with vlan that already exists in the zone
             if (ntwkOff.getGuestType() == GuestType.Isolated) {