diff --git a/openbsc/src/libmgcp/mgcp_protocol.c b/openbsc/src/libmgcp/mgcp_protocol.c
index 0989cc6..0681c10 100644
--- a/openbsc/src/libmgcp/mgcp_protocol.c
+++ b/openbsc/src/libmgcp/mgcp_protocol.c
@@ -879,6 +879,24 @@
 	return rtp->rate * f * rtp->frame_duration_num / rtp->frame_duration_den;
 }
 
+static int mgcp_osmux_setup(struct mgcp_endpoint *endp)
+{
+	if (!endp->cfg->osmux_init) {
+		if (osmux_init(OSMUX_ROLE_BSC, endp->cfg) < 0) {
+			LOGP(DMGCP, LOGL_ERROR, "Cannot init OSMUX\n");
+			return -1;
+		}
+		LOGP(DMGCP, LOGL_NOTICE, "OSMUX socket has been set up\n");
+	}
+
+	if (osmux_enable_endpoint(endp, OSMUX_ROLE_BSC) < 0) {
+		LOGP(DMGCP, LOGL_ERROR,
+		     "Could not activate Osmux in endpoint %d\n",
+		     ENDPOINT_NUMBER(endp));
+	}
+	return 0;
+}
+
 static struct msgb *handle_create_con(struct mgcp_parse_data *p)
 {
 	struct mgcp_trunk_config *tcfg;
@@ -910,12 +928,8 @@
 			mode = (const char *) line + 3;
 			break;
 		case 'X':
-			if (strcmp("Osmux: on", line + 2) == 0 &&
-			    osmux_enable_endpoint(endp, OSMUX_ROLE_BSC) < 0) {
-				LOGP(DMGCP, LOGL_ERROR,
-				     "Could not activate osmux in endpoint %d\n",
-				     ENDPOINT_NUMBER(endp));
-			}
+			if (strcmp("Osmux: on", line + 2) == 0)
+				mgcp_osmux_setup(endp);
 			break;
 		case '\0':
 			have_sdp = 1;
diff --git a/openbsc/src/libmgcp/osmux.c b/openbsc/src/libmgcp/osmux.c
index a6deeaa..1370c9f 100644
--- a/openbsc/src/libmgcp/osmux.c
+++ b/openbsc/src/libmgcp/osmux.c
@@ -439,14 +439,6 @@
 	 */
 	static const uint32_t rtp_ssrc_winlen = UINT32_MAX / 256;
 
-	if (!endp->cfg->osmux_init) {
-		if (osmux_init(role, endp->cfg) < 0) {
-			LOGP(DMGCP, LOGL_ERROR, "Cannot init OSMUX\n");
-			return -1;
-		}
-		LOGP(DMGCP, LOGL_NOTICE, "OSMUX requested, ENABLING.\n");
-	}
-
 	osmux_xfrm_output_init(&endp->osmux.out,
 			       (endp->ci * rtp_ssrc_winlen) +
 			       (random() % rtp_ssrc_winlen));
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c b/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
index ab89db8..5229976 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
@@ -33,6 +33,7 @@
 #include <osmocom/core/utils.h>
 #include <osmocom/vty/logging.h>
 #include <osmocom/vty/misc.h>
+#include <openbsc/osmux.h>
 
 #include <osmocom/sccp/sccp.h>
 
@@ -1184,12 +1185,27 @@
        OSMUX_STR "Enable OSMUX\n" "Disable OSMUX\n")
 {
 	struct bsc_config *conf = vty->index;
+	int old = conf->osmux;
 
 	if (strcmp(argv[0], "on") == 0)
 		conf->osmux = 1;
 	else if (strcmp(argv[0], "off") == 0)
 		conf->osmux = 0;
 
+	if (old == 0 && conf->osmux == 1) {
+		if (osmux_init(OSMUX_ROLE_BSC_NAT, conf->nat->mgcp_cfg) < 0) {
+			LOGP(DMGCP, LOGL_ERROR, "Cannot init OSMUX\n");
+			return -1;
+		}
+		LOGP(DMGCP, LOGL_NOTICE, "Setting up OSMUX socket\n");
+	} else if (old == 1 && conf->osmux == 0) {
+		LOGP(DMGCP, LOGL_NOTICE, "Disabling OSMUX socket\n");
+		/* Don't stop the socket, we may already have ongoing voice
+		 * flows already using Osmux. This just switch indicates that
+		 * new upcoming flows should use RTP.
+		 */
+	}
+
 	return CMD_SUCCESS;
 }