--- qemu/vl.c	2007-01-07 16:04:40.000000000 -0600
+++ vl.c	2007-01-09 12:16:09.000000000 -0600
@@ -3885,9 +3885,11 @@
             ret = -1;
             if (net_tap_fd_init(vlan, fd))
                 ret = 0;
         } else {
-            get_param_value(ifname, sizeof(ifname), "ifname", p);
+            if (get_param_value(ifname, sizeof(ifname), "ifname", p) == 0) {
+               ifname[0]='\0';
+            }
             if (get_param_value(setup_script, sizeof(setup_script), "script", p) == 0) {
                 pstrcpy(setup_script, sizeof(setup_script), DEFAULT_NETWORK_SCRIPT);
             }
             ret = net_tap_init(vlan, ifname, setup_script);