diff --git a/instances/templates/instance.html b/instances/templates/instance.html
index f9e343f..4287379 100644
--- a/instances/templates/instance.html
+++ b/instances/templates/instance.html
@@ -730,6 +730,8 @@
                                                                 <div class="col-sm-4">
                                                                     <button type="button" class="btn btn-sm btn-success pull-left" name="random-mac-{{ forloop.counter0 }}"
                                                                             onclick="random_mac({{ forloop.counter0 }})" style="margin-top: 2px;">{% trans "Random" %}</button>
+                                                                    <button type="button" class="btn btn-sm btn-success pull-left" name="guess-mac-{{ forloop.counter0 }}"
+                                                                            onclick="guess_mac_address({{ forloop.counter0 }})" style="margin-top: 2px;">{% trans "Guess" %}</button>
                                                                 </div>
                                                             </div>
                                                         {% endfor %}
@@ -964,6 +966,14 @@
         }
     }
 </script>
+<script>
+    function guess_mac_address(net) {
+        new_vname = $('#clone_name').val();
+        $.getJSON('/instance/guess_mac_address/' + new_vname + '/', function(data) {
+            $('input[name="net-'+net+'"]').val(data['mac']);
+        });
+    }
+</script>
 <script>
     function update_clone_disk_name(new_vname) {
         vname = '{{ vname }}-clone';
diff --git a/instances/urls.py b/instances/urls.py
index ce53b89..c1b2841 100644
--- a/instances/urls.py
+++ b/instances/urls.py
@@ -8,4 +8,6 @@ urlpatterns = [
         views.inst_graph, name='inst_graph'),
     url(r'^status/(?P<compute_id>[0-9]+)/(?P<vname>[\w\-\.]+)/$',
         views.inst_status, name='inst_status'),
+    url(r'^guess_mac_address/(?P<vname>[\w\-\.]+)/$',
+        views.guess_mac_address, name='guess_mac_address'),
 ]
diff --git a/instances/views.py b/instances/views.py
index 34bf678..92c59fb 100644
--- a/instances/views.py
+++ b/instances/views.py
@@ -666,3 +666,17 @@ def inst_graph(request, compute_id, vname):
 
     response.write(data)
     return response
+
+@login_required
+def guess_mac_address(request, vname):
+    dhcp_file = '/srv/webvirtcloud/dhcpd.hype.ipv4.conf'
+    data = { 'vname': vname, 'mac': '52:54:00:' }
+    with open(dhcp_file, 'r') as f:
+        name_found = False
+        for line in f:
+            if "host %s." % vname in line:
+                name_found = True
+            if name_found and "hardware ethernet" in line:
+                data['mac'] = line.split(' ')[-1].strip().strip(';')
+                break
+    return HttpResponse(json.dumps(data));