diff --git a/config.c b/config.c
index 86ea354..00c76c3 100644
--- a/config.c
+++ b/config.c
@@ -206,6 +206,7 @@ struct config_item config_tab[] = {
 	GLOB_ITEM_INT("max_frequency", 900000000, 0, INT_MAX),
 	PORT_ITEM_INT("min_neighbor_prop_delay", -20000000, INT_MIN, -1),
 	PORT_ITEM_INT("neighborPropDelayThresh", 20000000, 0, INT_MAX),
+	PORT_ITEM_INT("net_sync_monitor", 0, 0, 1),
 	PORT_ITEM_ENU("network_transport", TRANS_UDP_IPV4, nw_trans_enu),
 	GLOB_ITEM_INT("ntpshm_segment", 0, INT_MIN, INT_MAX),
 	GLOB_ITEM_INT("offsetScaledLogVariance", 0xffff, 0, UINT16_MAX),
diff --git a/default.cfg b/default.cfg
index ebb263a..e76aeae 100644
--- a/default.cfg
+++ b/default.cfg
@@ -35,6 +35,7 @@ logging_level		6
 path_trace_enabled	0
 follow_up_info		0
 hybrid_e2e		0
+net_sync_monitor	0
 tx_timestamp_timeout	1
 use_syslog		1
 verbose			0
diff --git a/gPTP.cfg b/gPTP.cfg
index 142996a..1e7a33e 100644
--- a/gPTP.cfg
+++ b/gPTP.cfg
@@ -33,6 +33,7 @@ logging_level		6
 path_trace_enabled	1
 follow_up_info		1
 hybrid_e2e		0
+net_sync_monitor	0
 tx_timestamp_timeout	1
 use_syslog		1
 verbose			0
diff --git a/port.c b/port.c
index 88481ff..25507e2 100644
--- a/port.c
+++ b/port.c
@@ -2834,6 +2834,7 @@ struct port *port_open(int phc_index,
 	p->follow_up_info = config_get_int(cfg, p->name, "follow_up_info");
 	p->freq_est_interval = config_get_int(cfg, p->name, "freq_est_interval");
 	p->hybrid_e2e = config_get_int(cfg, p->name, "hybrid_e2e");
+	p->net_sync_monitor = config_get_int(cfg, p->name, "net_sync_monitor");
 	p->path_trace_enabled = config_get_int(cfg, p->name, "path_trace_enabled");
 	p->rx_timestamp_offset = config_get_int(cfg, p->name, "ingressLatency");
 	p->tx_timestamp_offset = config_get_int(cfg, p->name, "egressLatency");
diff --git a/ptp4l.8 b/ptp4l.8
index 9a7701d..950e07c 100644
--- a/ptp4l.8
+++ b/ptp4l.8
@@ -1,4 +1,4 @@
-.TH PTP4l 8 "December 2016" "linuxptp"
+.TH PTP4l 8 "Novemver 2017" "linuxptp"
 .SH NAME
 ptp4l - PTP Boundary/Ordinary Clock
 
@@ -219,6 +219,16 @@ delay requests using unicast delay responses. This option has no
 effect if the delay_mechanism is set to P2P.
 The default is 0 (disabled).
 .TP
+.B net_sync_monitor
+Enables the NetSync Monitor (NSM) protocol. The NSM protocol allows a
+station to measure how well another node is synchronized. The monitor
+sends a unicast delay request to the node, which replies
+unconditionally with unicast delay response, sync, and follow up
+messages. If the monitor is synchronized to the GM, it can use the
+time stamps in the message to estimate the node's offset.  This option
+requires that the 'hybrid_e2e' option be enabled as well.
+The default is 0 (disabled).
+.TP
 .B ptp_dst_mac
 The MAC address to which PTP messages should be sent.
 Relevant only with L2 transport. The default is 01:1B:19:00:00:00.