diff --git a/server/src/com/cloud/network/router/VirtualNetworkApplianceManagerImpl.java b/server/src/com/cloud/network/router/VirtualNetworkApplianceManagerImpl.java
index b5aed7e089b..2488c680db2 100755
--- a/server/src/com/cloud/network/router/VirtualNetworkApplianceManagerImpl.java
+++ b/server/src/com/cloud/network/router/VirtualNetworkApplianceManagerImpl.java
@@ -1717,7 +1717,9 @@ public class VirtualNetworkApplianceManagerImpl implements VirtualNetworkApplian
          * to return DNS server rather than 
          * virtual router itself. */
         if (dnsProvided || dhcpProvided) {
-            buf.append(" dns1=").append(defaultDns1);
+            if (defaultDns1 != null) {
+                buf.append(" dns1=").append(defaultDns1);
+            }
             if (defaultDns2 != null) {
                 buf.append(" dns2=").append(defaultDns2);
             }