Index: utils/net_ads.c
===================================================================
--- utils/net_ads.c	(revision 5952)
+++ utils/net_ads.c	(working copy)
@@ -94,8 +94,13 @@
 {
 	ADS_STRUCT *ads;
 
-	ads = ads_init(NULL, opt_target_workgroup, opt_host);
+	/* if netbios is disabled we have to default to the realm from smb.conf */
 
+	if ( lp_disable_netbios() && *lp_realm() )
+		ads = ads_init(lp_realm(), opt_target_workgroup, opt_host);
+	else
+		ads = ads_init(NULL, opt_target_workgroup, opt_host);
+
 	if (ads) {
 		ads->auth.flags |= ADS_AUTH_NO_BIND;
 	}