diff --git a/openbsc/include/openbsc/signal.h b/openbsc/include/openbsc/signal.h
index c065f90..b41182d 100644
--- a/openbsc/include/openbsc/signal.h
+++ b/openbsc/include/openbsc/signal.h
@@ -55,6 +55,7 @@
 	S_NM_SW_ACTIV_REP,	/* GSM 12.21 software activated report */
 	S_NM_FAIL_REP,		/* GSM 12.21 failure event report */
 	S_NM_NACK,		/* GSM 12.21 various NM_MT_*_NACK happened */
+	S_NM_IPACC_NACK,	/* GSM 12.21 nanoBTS extensions NM_MT_IPACC_*_*_NACK happened */
 };
 
 /* SS_LCHAN signals */
diff --git a/openbsc/src/abis_nm.c b/openbsc/src/abis_nm.c
index 0ec0640..7e016db 100644
--- a/openbsc/src/abis_nm.c
+++ b/openbsc/src/abis_nm.c
@@ -2309,6 +2309,18 @@
 		DEBUGPC(DNM, "unknown\n");
 		break;
 	}
+
+	/* signal handling */
+	switch  (foh->msg_type) {
+	case NM_MT_IPACC_RSL_CONNECT_NACK:
+	case NM_MT_IPACC_SET_NVATTR_NACK:
+	case NM_MT_IPACC_GET_NVATTR_NACK:
+		dispatch_signal(SS_NM, S_NM_IPACC_NACK, (void*) ((long)foh->msg_type));
+		break;
+	default:
+		break;
+	}
+
 	return 0;
 }
 
diff --git a/openbsc/src/ipaccess-config.c b/openbsc/src/ipaccess-config.c
index ec145e5..52e9cc9 100644
--- a/openbsc/src/ipaccess-config.c
+++ b/openbsc/src/ipaccess-config.c
@@ -37,6 +37,7 @@
 #include <openbsc/gsm_data.h>
 #include <openbsc/e1_input.h>
 #include <openbsc/abis_nm.h>
+#include <openbsc/signal.h>
 
 static struct gsm_network *gsmnet;
 
@@ -51,6 +52,33 @@
 static u_int8_t unit_id_attr[] = { 0x91, 0x00, 9, '2', '3', '4', '2', '/' , '0', '/', '0', 0x00 };
 */
 
+/*
+ * Callback function for NACK on the OML NM
+ *
+ * Currently we send the config requests but don't check the
+ * result. The nanoBTS will send us a NACK when we did something the
+ * BTS didn't like.
+ */
+static int ipacc_msg_nack(int mt)
+{
+	fprintf(stderr, "Failure to set attribute. This seems fatal\n");
+	exit(-1);
+	return 0;
+}
+
+static int nm_sig_cb(unsigned int subsys, unsigned int signal,
+		     void *handler_data, void *signal_data)
+{
+	switch (signal) {
+	case S_NM_IPACC_NACK:
+		return ipacc_msg_nack((int)signal_data);
+	default:
+		break;
+	}
+
+	return 0;
+}
+
 static void bootstrap_om(struct gsm_bts *bts)
 {
 	int len;
@@ -223,6 +251,7 @@
 	bts = gsm_bts_alloc(gsmnet, GSM_BTS_TYPE_NANOBTS_900, HARDCODED_TSC,
 				HARDCODED_BSIC);
 	
+	register_signal_handler(SS_NM, nm_sig_cb, NULL);
 	printf("Trying to connect to ip.access BTS ...\n");
 
 	memset(&sin, 0, sizeof(sin));