diff --git a/lib/vagrant-libvirt/templates/private_network.xml.erb b/lib/vagrant-libvirt/templates/private_network.xml.erb
index 5d969b0..3d7fb52 100644
--- a/lib/vagrant-libvirt/templates/private_network.xml.erb
+++ b/lib/vagrant-libvirt/templates/private_network.xml.erb
@@ -18,7 +18,7 @@
     <% end %>
   <% end %>
 
-  <% if @network_forward_mode != 'veryisolated' %>
+  <% if @network_forward_mode != 'veryisolated' && !@network_address.nil? %>
     <ip address="<%= @network_address %>" netmask="<%= @network_netmask %>">
     <% if @tftp_root %>
       <tftp root="<%= @tftp_root %>" />