diff --git a/openbsc/include/openbsc/db.h b/openbsc/include/openbsc/db.h
index 6ffe1ad..bb90705 100644
--- a/openbsc/include/openbsc/db.h
+++ b/openbsc/include/openbsc/db.h
@@ -20,6 +20,8 @@
 #ifndef _DB_H
 #define _DB_H
 
+#include <stdbool.h>
+
 #include "gsm_subscriber.h"
 
 struct gsm_equipment;
@@ -36,7 +38,7 @@
 
 /* subscriber management */
 struct gsm_subscriber *db_create_subscriber(const char *imsi, uint64_t smin,
-					    uint64_t smax);
+					    uint64_t smax, bool alloc_exten);
 struct gsm_subscriber *db_get_subscriber(enum gsm_subscriber_field field,
 					 const char *subscr);
 int db_sync_subscriber(struct gsm_subscriber *subscriber);
diff --git a/openbsc/include/openbsc/gsm_data.h b/openbsc/include/openbsc/gsm_data.h
index e7cd520..bdcd0e0 100644
--- a/openbsc/include/openbsc/gsm_data.h
+++ b/openbsc/include/openbsc/gsm_data.h
@@ -4,6 +4,7 @@
 #include <stdint.h>
 #include <regex.h>
 #include <sys/types.h>
+#include <stdbool.h>
 
 #include <osmocom/core/timer.h>
 #include <osmocom/core/select.h>
@@ -21,12 +22,6 @@
 
 #define OBSC_LINKID_CB(__msgb)	(__msgb)->cb[3]
 
-enum gsm_subscr_creation_mode {
-	GSM_SUBSCR_DONT_CREATE = 0,
-	GSM_SUBSCR_CREAT_W_RAND_EXT = 1,
-	GSM_SUBSCR_CREAT_W_REGEXP = 2,
-};
-
 enum gsm_security_event {
 	GSM_SECURITY_NOAVAIL,
 	GSM_SECURITY_AUTH_FAILED,
@@ -289,7 +284,8 @@
 	struct osmo_bsc_data *bsc_data;
 
 	/* subscriber related features */
-	int subscr_creation_mode;
+	bool auto_create_subscr;
+	bool auto_assign_exten;
 	uint64_t ext_min;
 	uint64_t ext_max;
 	struct gsm_subscriber_group *subscr_group;
diff --git a/openbsc/include/openbsc/gsm_subscriber.h b/openbsc/include/openbsc/gsm_subscriber.h
index 3cba5d1..3d7c244 100644
--- a/openbsc/include/openbsc/gsm_subscriber.h
+++ b/openbsc/include/openbsc/gsm_subscriber.h
@@ -5,6 +5,8 @@
 #include <osmocom/core/linuxlist.h>
 #include <osmocom/gsm/protocol/gsm_23_003.h>
 
+#include <stdbool.h>
+
 #define GSM_NAME_LENGTH 160
 
 #define GSM_EXTENSION_LENGTH 15 /* MSISDN can only be 15 digits length */
@@ -90,8 +92,7 @@
 struct gsm_subscriber *subscr_get(struct gsm_subscriber *subscr);
 struct gsm_subscriber *subscr_put(struct gsm_subscriber *subscr);
 struct gsm_subscriber *subscr_create_subscriber(struct gsm_subscriber_group *sgrp,
-						const char *imsi, uint64_t smin,
-						uint64_t smax);
+						const char *imsi);
 struct gsm_subscriber *subscr_get_by_tmsi(struct gsm_subscriber_group *sgrp,
 					  uint32_t tmsi);
 struct gsm_subscriber *subscr_get_by_imsi(struct gsm_subscriber_group *sgrp,
diff --git a/openbsc/src/libbsc/bsc_vty.c b/openbsc/src/libbsc/bsc_vty.c
index 04f2cc6..b0e8764 100644
--- a/openbsc/src/libbsc/bsc_vty.c
+++ b/openbsc/src/libbsc/bsc_vty.c
@@ -195,6 +195,10 @@
 	if (net->authorized_reg_str)
 		vty_out(vty, ", authorized regexp: %s", net->authorized_reg_str);
 	vty_out(vty, "%s", VTY_NEWLINE);
+	vty_out(vty, "  Auto create subscriber: %s%s",
+		net->auto_create_subscr ? "yes" : "no", VTY_NEWLINE);
+	vty_out(vty, "  Auto assign extension: %s%s",
+		net->auto_assign_exten ? "yes" : "no", VTY_NEWLINE);
 	vty_out(vty, "  Location updating reject cause: %u%s",
 		net->reject_cause, VTY_NEWLINE);
 	vty_out(vty, "  Encryption: A5/%u%s", net->a5_encryption,
diff --git a/openbsc/src/libbsc/net_init.c b/openbsc/src/libbsc/net_init.c
index 4636d57..0e99097 100644
--- a/openbsc/src/libbsc/net_init.c
+++ b/openbsc/src/libbsc/net_init.c
@@ -21,10 +21,13 @@
 #include <openbsc/osmo_msc_data.h>
 #include <openbsc/gsm_subscriber.h>
 
+#include <stdbool.h>
+
 struct gsm_network *gsm_network_init(uint16_t country_code, uint16_t network_code,
 				     int (*mncc_recv)(struct gsm_network *, struct msgb *))
 {
 	struct gsm_network *net;
+	const char *default_regexp = "*";
 
 	net = talloc_zero(tall_bsc_ctx, struct gsm_network);
 	if (!net)
@@ -42,13 +45,18 @@
 		return NULL;
 	}
 
+	if (gsm_parse_reg(net, &net->authorized_regexp, &net->authorized_reg_str, 1,
+			  &default_regexp) != 0)
+		return NULL;
+
 	/* Init back pointer */
 	net->bsc_data->auto_off_timeout = -1;
 	net->bsc_data->network = net;
 	INIT_LLIST_HEAD(&net->bsc_data->mscs);
 
 	net->subscr_group->net = net;
-	net->subscr_creation_mode = GSM_SUBSCR_CREAT_W_RAND_EXT;
+	net->auto_create_subscr = true;
+	net->auto_assign_exten = true;
 
 	net->country_code = country_code;
 	net->network_code = network_code;
diff --git a/openbsc/src/libmsc/ctrl_commands.c b/openbsc/src/libmsc/ctrl_commands.c
index a02db36..79e136d 100644
--- a/openbsc/src/libmsc/ctrl_commands.c
+++ b/openbsc/src/libmsc/ctrl_commands.c
@@ -25,6 +25,8 @@
 #include <openbsc/db.h>
 #include <openbsc/debug.h>
 
+#include <stdbool.h>
+
 static bool alg_supported(const char *alg)
 {
 	/*
@@ -96,9 +98,7 @@
 
 	subscr = subscr_get_by_imsi(net->subscr_group, imsi);
 	if (!subscr)
-		subscr = subscr_create_subscriber(net->subscr_group, imsi,
-						  net->ext_min,
-						  net->ext_max);
+		subscr = subscr_create_subscriber(net->subscr_group, imsi);
 	if (!subscr)
 		goto fail;
 
diff --git a/openbsc/src/libmsc/db.c b/openbsc/src/libmsc/db.c
index b367139..68eba3e 100644
--- a/openbsc/src/libmsc/db.c
+++ b/openbsc/src/libmsc/db.c
@@ -23,6 +23,7 @@
 #include <inttypes.h>
 #include <libgen.h>
 #include <stdio.h>
+#include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
@@ -519,7 +520,7 @@
 }
 
 struct gsm_subscriber *db_create_subscriber(const char *imsi, uint64_t smin,
-					    uint64_t smax)
+					    uint64_t smax, bool alloc_exten)
 {
 	dbi_result result;
 	struct gsm_subscriber *subscr;
@@ -551,7 +552,8 @@
 	strncpy(subscr->imsi, imsi, sizeof(subscr->imsi)-1);
 	dbi_result_free(result);
 	LOGP(DDB, LOGL_INFO, "New Subscriber: ID %llu, IMSI %s\n", subscr->id, subscr->imsi);
-	db_subscriber_alloc_exten(subscr, smin, smax);
+	if (alloc_exten)
+		db_subscriber_alloc_exten(subscr, smin, smax);
 	return subscr;
 }
 
@@ -956,8 +958,11 @@
 
 	dbi_conn_quote_string_copy(conn, 
 				   subscriber->name, &q_name);
-	dbi_conn_quote_string_copy(conn, 
-				   subscriber->extension, &q_extension);
+	if (subscriber->extension[0] != '\0')
+		dbi_conn_quote_string_copy(conn,
+					   subscriber->extension, &q_extension);
+	else
+		q_extension = strdup("NULL");
 	
 	if (subscriber->tmsi != GSM_RESERVED_TMSI) {
 		sprintf(tmsi, "%u", subscriber->tmsi);
@@ -1062,15 +1067,17 @@
 	}
 	dbi_result_free(result);
 
-	result = dbi_conn_queryf(conn,
-			"DELETE FROM SMS WHERE src_addr=%s OR dest_addr=%s",
-			subscr->extension, subscr->extension);
-	if (!result) {
-		LOGP(DDB, LOGL_ERROR,
-			"Failed to delete SMS for %llu\n", subscr->id);
-		return -1;
+	if (subscr->extension[0] != '\0') {
+		result = dbi_conn_queryf(conn,
+			    "DELETE FROM SMS WHERE src_addr=%s OR dest_addr=%s",
+					 subscr->extension, subscr->extension);
+		if (!result) {
+			LOGP(DDB, LOGL_ERROR,
+			     "Failed to delete SMS for %llu\n", subscr->id);
+			return -1;
+		}
+		dbi_result_free(result);
 	}
-	dbi_result_free(result);
 
 	result = dbi_conn_queryf(conn,
 			"DELETE FROM VLR WHERE subscriber_id=%llu",
diff --git a/openbsc/src/libmsc/gsm_04_08.c b/openbsc/src/libmsc/gsm_04_08.c
index 6704497..1b02efe 100644
--- a/openbsc/src/libmsc/gsm_04_08.c
+++ b/openbsc/src/libmsc/gsm_04_08.c
@@ -530,15 +530,13 @@
 static struct gsm_subscriber *subscr_create(const struct gsm_network *net,
 					    const char *imsi)
 {
-	if (net->subscr_creation_mode == GSM_SUBSCR_DONT_CREATE)
+	if (!net->auto_create_subscr)
 		return NULL;
 
-	if (net->subscr_creation_mode & GSM_SUBSCR_CREAT_W_REGEXP)
-		if (!subscr_regexp_check(net, imsi))
-			return NULL;
+	if (!subscr_regexp_check(net, imsi))
+		return NULL;
 
-	return subscr_create_subscriber(net->subscr_group, imsi, net->ext_min,
-					net->ext_max);
+	return subscr_create_subscriber(net->subscr_group, imsi);
 }
 
 /* Parse Chapter 9.2.11 Identity Response */
diff --git a/openbsc/src/libmsc/gsm_subscriber.c b/openbsc/src/libmsc/gsm_subscriber.c
index 1dc2cc2..08198c7 100644
--- a/openbsc/src/libmsc/gsm_subscriber.c
+++ b/openbsc/src/libmsc/gsm_subscriber.c
@@ -26,6 +26,7 @@
 #include <string.h>
 #include <assert.h>
 #include <time.h>
+#include <stdbool.h>
 
 #include <osmocom/core/talloc.h>
 
@@ -203,10 +204,12 @@
 }
 
 struct gsm_subscriber *subscr_create_subscriber(struct gsm_subscriber_group *sgrp,
-						const char *imsi, uint64_t smin,
-						uint64_t smax)
+						const char *imsi)
 {
-	struct gsm_subscriber *subscr = db_create_subscriber(imsi, smin, smax);
+	struct gsm_subscriber *subscr = db_create_subscriber(imsi,
+							     sgrp->net->ext_min,
+							     sgrp->net->ext_max,
+							     sgrp->net->auto_assign_exten);
 	if (subscr)
 		subscr->group = sgrp;
 	return subscr;
diff --git a/openbsc/src/libmsc/vty_interface_layer3.c b/openbsc/src/libmsc/vty_interface_layer3.c
index a035bf9..74da1d7 100644
--- a/openbsc/src/libmsc/vty_interface_layer3.c
+++ b/openbsc/src/libmsc/vty_interface_layer3.c
@@ -242,9 +242,7 @@
 	if (subscr)
 		db_sync_subscriber(subscr);
 	else {
-		subscr = subscr_create_subscriber(gsmnet->subscr_group, argv[0],
-						  gsmnet->ext_min,
-						  gsmnet->ext_max);
+		subscr = subscr_create_subscriber(gsmnet->subscr_group, argv[0]);
 
 		if (!subscr) {
 			vty_out(vty, "%% No subscriber created for IMSI %s%s",
@@ -1044,6 +1042,8 @@
 {
 	struct gsm_network *gsmnet = gsmnet_from_vty(vty);
 	uint64_t mi = atoi(argv[0]), ma = atoi(argv[1]);
+	gsmnet->auto_create_subscr = true;
+	gsmnet->auto_assign_exten = true;
 	if (mi >= ma) {
 		vty_out(vty, "Incorrect range: %s >= %s, expected MIN < MAX%s",
 			argv[0], argv[1], VTY_NEWLINE);
@@ -1055,15 +1055,13 @@
 }
 
 DEFUN(cfg_nitb_subscr_create, cfg_nitb_subscr_create_cmd,
-      "subscriber-create-on-demand [regexp]",
+      "subscriber-create-on-demand [no-extension]",
       "Make a new record when a subscriber is first seen.\n"
-      "Create subscribers only if IMSI matches the regexp specified in "
-      "authorized-regexp command\n")
+      "Do not automatically assign extension to created subscribers\n")
 {
 	struct gsm_network *gsmnet = gsmnet_from_vty(vty);
-	gsmnet->subscr_creation_mode = GSM_SUBSCR_CREAT_W_RAND_EXT;
-	if (argc)
-		gsmnet->subscr_creation_mode |= GSM_SUBSCR_CREAT_W_REGEXP;
+	gsmnet->auto_create_subscr = true;
+	gsmnet->auto_assign_exten = argc ? false : true;
 	return CMD_SUCCESS;
 }
 
@@ -1072,7 +1070,7 @@
       NO_STR "Make a new record when a subscriber is first seen.\n")
 {
 	struct gsm_network *gsmnet = gsmnet_from_vty(vty);
-	gsmnet->subscr_creation_mode = GSM_SUBSCR_DONT_CREATE;
+	gsmnet->auto_create_subscr = false;
 	return CMD_SUCCESS;
 }
 
@@ -1097,12 +1095,15 @@
 static int config_write_nitb(struct vty *vty)
 {
 	struct gsm_network *gsmnet = gsmnet_from_vty(vty);
-	enum gsm_subscr_creation_mode scm = gsmnet->subscr_creation_mode;
-	const char *reg = (scm & GSM_SUBSCR_CREAT_W_REGEXP) ? " regexp" : "",
-		*pref = scm ? "" : "no ";
+
 	vty_out(vty, "nitb%s", VTY_NEWLINE);
-	vty_out(vty, " %ssubscriber-create-on-demand%s%s",
-		pref, reg, VTY_NEWLINE);
+	if (!gsmnet->auto_create_subscr)
+		vty_out(vty, " no subscriber-create-on-demand%s", VTY_NEWLINE);
+	else
+		vty_out(vty, " subscriber-create-on-demand%s%s",
+			gsmnet->auto_assign_exten ? "" : " no-extension",
+			VTY_NEWLINE);
+
 	if (gsmnet->ext_min != GSM_MIN_EXTEN || gsmnet->ext_max != GSM_MAX_EXTEN)
 		vty_out(vty, " subscriber-create-on-demand random %"PRIu64" %"
 			PRIu64"%s", gsmnet->ext_min, gsmnet->ext_max,
diff --git a/openbsc/tests/db/db_test.c b/openbsc/tests/db/db_test.c
index dc81481..755a6e9 100644
--- a/openbsc/tests/db/db_test.c
+++ b/openbsc/tests/db/db_test.c
@@ -28,6 +28,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
+#include <stdbool.h>
 #include <inttypes.h>
 
 static struct gsm_network dummy_net;
@@ -159,12 +160,13 @@
 	subscr_put(rcv_subscr);
 }
 
-static void test_subs(const char *alice_imsi, char *imei1, char *imei2)
+static void test_subs(const char *imsi, char *imei1, char *imei2, bool make_ext)
 {
 	struct gsm_subscriber *alice = NULL, *alice_db;
 	char scratch_str[256];
 
-	alice = db_create_subscriber(alice_imsi, GSM_MIN_EXTEN, GSM_MAX_EXTEN);
+	alice = db_create_subscriber(imsi, GSM_MIN_EXTEN, GSM_MAX_EXTEN,
+				     make_ext);
 	db_subscriber_assoc_imei(alice, imei1);
 	if (imei2)
 		db_subscriber_assoc_imei(alice, imei2);
@@ -177,7 +179,7 @@
 	COMPARE(alice, alice_db);
 	SUBSCR_PUT(alice_db);
 	/* Get by IMSI */
-	alice_db = db_get_subscriber(GSM_SUBSCRIBER_IMSI, alice_imsi);
+	alice_db = db_get_subscriber(GSM_SUBSCRIBER_IMSI, imsi);
 	COMPARE(alice, alice_db);
 	SUBSCR_PUT(alice_db);
 	/* Get by id */
@@ -187,8 +189,14 @@
 	SUBSCR_PUT(alice_db);
 	/* Get by extension */
 	alice_db = db_get_subscriber(GSM_SUBSCRIBER_EXTENSION, alice->extension);
-	COMPARE(alice, alice_db);
-	SUBSCR_PUT(alice_db);
+	if (alice_db) {
+		if (!make_ext)
+			printf("FAIL: bogus extension created for IMSI %s\n",
+			       imsi);
+		COMPARE(alice, alice_db);
+		SUBSCR_PUT(alice_db);
+	} else if (make_ext)
+		printf("FAIL: no subscriber extension for IMSI %s\n", imsi);
 	SUBSCR_PUT(alice);
 }
 
@@ -217,18 +225,22 @@
 	struct gsm_subscriber *alice_db;
 
 	char *alice_imsi = "3243245432345";
-	alice = db_create_subscriber(alice_imsi, GSM_MIN_EXTEN, GSM_MAX_EXTEN);
+	alice = db_create_subscriber(alice_imsi, GSM_MIN_EXTEN, GSM_MAX_EXTEN,
+				     true);
 	db_sync_subscriber(alice);
 	alice_db = db_get_subscriber(GSM_SUBSCRIBER_IMSI, alice->imsi);
 	COMPARE(alice, alice_db);
 	SUBSCR_PUT(alice_db);
 	SUBSCR_PUT(alice);
 
-	test_subs("3693245423445", "1234567890", NULL);
-	test_subs("9993245423445", "1234567890", "6543560920");
+	test_subs("3693245423445", "1234567890", NULL, true);
+	test_subs("9993245423445", "1234567890", "6543560920", true);
+	test_subs("3123122223445", "1234567890", NULL, false);
+	test_subs("9123121223445", "1234567890", "6543560920", false);
 
 	/* create it again and see it fails */
-	alice = db_create_subscriber(alice_imsi, GSM_MIN_EXTEN, GSM_MAX_EXTEN);
+	alice = db_create_subscriber(alice_imsi, GSM_MIN_EXTEN, GSM_MAX_EXTEN,
+				     true);
 	OSMO_ASSERT(!alice);
 
 	test_sms();
diff --git a/openbsc/tests/vty_test_runner.py b/openbsc/tests/vty_test_runner.py
index bae1866..23939e8 100644
--- a/openbsc/tests/vty_test_runner.py
+++ b/openbsc/tests/vty_test_runner.py
@@ -244,7 +244,7 @@
         self.vty.command("configure terminal")
         self.vty.command("nitb")
         self.assertTrue(self.vty.verify("subscriber-create-on-demand", ['']))
-        self.assertTrue(self.vty.verify("subscriber-create-on-demand regexp", ['']))
+        self.assertTrue(self.vty.verify("subscriber-create-on-demand no-extension", ['']))
         self.vty.command("end")
 
     def testSi2Q(self):
@@ -400,6 +400,9 @@
         self.vty.enable()
 
         imsi = "204300854013739"
+        imsi2 = "222301824913762"
+        imsi3 = "333500854113763"
+        imsi4 = "444583744053764"
 
         # Initially we don't have this subscriber
         self.vty.verify('show subscriber imsi '+imsi, ['% No subscriber found for imsi '+imsi])
@@ -407,14 +410,60 @@
         # Lets create one
         res = self.vty.command('subscriber create imsi '+imsi)
         self.assert_(res.find("    IMSI: "+imsi) > 0)
+        self.assert_(res.find("Extension") > 0)
 
         # Now we have it
         res = self.vty.command('show subscriber imsi '+imsi)
         self.assert_(res.find("    IMSI: "+imsi) > 0)
 
+        # With narrow random interval
+        self.vty.command("configure terminal")
+        self.vty.command("nitb")
+        self.assertTrue(self.vty.verify("subscriber-create-on-demand", ['']))
+        # wrong interval
+        res = self.vty.command("subscriber-create-on-demand random 221 122")
+        # error string will contain arguments
+        self.assert_(res.find("122") > 0)
+        self.assert_(res.find("221") > 0)
+        # correct interval - silent ok
+        self.assertTrue(self.vty.verify("subscriber-create-on-demand random 221 222", ['']))
+        self.vty.command("end")
+
+        res = self.vty.command('subscriber create imsi ' + imsi2)
+        self.assert_(res.find("    IMSI: " + imsi2) > 0)
+        self.assert_(res.find("221") > 0 or res.find("222") > 0)
+        self.assert_(res.find("    Extension: ") > 0)
+
+        # Without extension
+        self.vty.command("configure terminal")
+        self.vty.command("nitb")
+        self.assertTrue(self.vty.verify("subscriber-create-on-demand no-extension", ['']))
+        self.vty.command("end")
+        res = self.vty.command('subscriber create imsi ' + imsi3)
+        self.assert_(res.find("    IMSI: " + imsi3) > 0)
+        self.assertEquals(res.find("Extension"), -1)
+
+        # With extension again
+        self.vty.command("configure terminal")
+        self.vty.command("nitb")
+        self.assertTrue(self.vty.verify("no subscriber-create-on-demand", ['']))
+        self.assertTrue(self.vty.verify("subscriber-create-on-demand", ['']))
+        self.assertTrue(self.vty.verify("subscriber-create-on-demand random 221 666", ['']))
+        self.vty.command("end")
+
+        res = self.vty.command('subscriber create imsi ' + imsi4)
+        self.assert_(res.find("    IMSI: " + imsi4) > 0)
+        self.assert_(res.find("    Extension: ") > 0)
+
         # Delete it
         res = self.vty.command('subscriber imsi ' + imsi + ' delete')
         self.assert_("" == res)
+        res = self.vty.command('subscriber imsi ' + imsi2 + ' delete')
+        self.assert_("" == res)
+        res = self.vty.command('subscriber imsi ' + imsi3 + ' delete')
+        self.assert_("" == res)
+        res = self.vty.command('subscriber imsi ' + imsi4 + ' delete')
+        self.assert_("" == res)
 
         # Now it should not be there anymore
         res = self.vty.command('show subscriber imsi '+imsi)