diff --git a/lib/guestfs-internal.h b/lib/guestfs-internal.h
index 0b46f0070..97a13ff2c 100644
--- a/lib/guestfs-internal.h
+++ b/lib/guestfs-internal.h
@@ -158,6 +158,12 @@
 #endif
 #endif
 
+/* Network address and network mask (expressed as address prefix) that the
+ * appliance will see (if networking is enabled).
+ */
+#define NETWORK_ADDRESS "169.254.0.0"
+#define NETWORK_PREFIX  "16"
+
 /* Guestfs handle and associated structures. */
 
 /* State. */
diff --git a/lib/launch-direct.c b/lib/launch-direct.c
index b6ed9766f..de17d2167 100644
--- a/lib/launch-direct.c
+++ b/lib/launch-direct.c
@@ -681,7 +681,7 @@ launch_direct (guestfs_h *g, void *datav, const char *arg)
     start_list ("-netdev") {
       append_list ("user");
       append_list ("id=usernet");
-      append_list ("net=169.254.0.0/16");
+      append_list ("net=" NETWORK_ADDRESS "/" NETWORK_PREFIX);
     } end_list ();
     start_list ("-device") {
       append_list (VIRTIO_DEVICE_NAME ("virtio-net"));
diff --git a/lib/launch-libvirt.c b/lib/launch-libvirt.c
index 5842319df..0f38f0aec 100644
--- a/lib/launch-libvirt.c
+++ b/lib/launch-libvirt.c
@@ -1826,7 +1826,8 @@ construct_libvirt_xml_qemu_cmdline (guestfs_h *g,
       } end_element ();
 
       start_element ("qemu:arg") {
-        attribute ("value", "user,id=usernet,net=169.254.0.0/16");
+        attribute ("value",
+                   "user,id=usernet,net=" NETWORK_ADDRESS "/" NETWORK_PREFIX);
       } end_element ();
 
       start_element ("qemu:arg") {