diff --git a/config.c b/config.c
index 0b656b7..acd5f45 100644
--- a/config.c
+++ b/config.c
@@ -214,6 +214,7 @@ struct config_item config_tab[] = {
 	PORT_ITEM_INT("logMinPdelayReqInterval", 0, INT8_MIN, INT8_MAX),
 	PORT_ITEM_INT("logSyncInterval", 0, INT8_MIN, INT8_MAX),
 	GLOB_ITEM_INT("logging_level", LOG_INFO, PRINT_LEVEL_MIN, PRINT_LEVEL_MAX),
+	PORT_ITEM_INT("masterOnly", 0, 0, 1),
 	GLOB_ITEM_STR("message_tag", NULL),
 	GLOB_ITEM_STR("manufacturerIdentity", "00:00:00"),
 	GLOB_ITEM_INT("max_frequency", 900000000, 0, INT_MAX),
diff --git a/default.cfg b/default.cfg
index d7b78f2..408022d 100644
--- a/default.cfg
+++ b/default.cfg
@@ -29,6 +29,7 @@ syncReceiptTimeout	0
 delayAsymmetry		0
 fault_reset_interval	4
 neighborPropDelayThresh	20000000
+masterOnly		0
 G.8275.portDS.localPriority	128
 #
 # Run time options
diff --git a/gPTP.cfg b/gPTP.cfg
index 14859e1..ed087fa 100644
--- a/gPTP.cfg
+++ b/gPTP.cfg
@@ -27,6 +27,7 @@ delayAsymmetry		0
 fault_reset_interval	4
 neighborPropDelayThresh	800
 min_neighbor_prop_delay	-20000000
+masterOnly		0
 G.8275.portDS.localPriority	128
 #
 # Run time options
diff --git a/port.c b/port.c
index 3279417..bc630b5 100644
--- a/port.c
+++ b/port.c
@@ -1568,6 +1568,7 @@ int port_initialize(struct port *p)
 	p->transportSpecific       = config_get_int(cfg, p->name, "transportSpecific");
 	p->transportSpecific     <<= 4;
 	p->match_transport_specific = !config_get_int(cfg, p->name, "ignore_transport_specific");
+	p->master_only             = config_get_int(cfg, p->name, "masterOnly");
 	p->localPriority           = config_get_int(cfg, p->name, "G.8275.portDS.localPriority");
 	p->logSyncInterval         = config_get_int(cfg, p->name, "logSyncInterval");
 	p->logMinPdelayReqInterval = config_get_int(cfg, p->name, "logMinPdelayReqInterval");
@@ -2200,6 +2201,9 @@ struct foreign_clock *port_compute_best(struct port *p)
 	dscmp = clock_dscmp(p->clock);
 	p->best = NULL;
 
+	if (p->master_only)
+		return p->best;
+
 	LIST_FOREACH(fc, &p->foreign_masters, list) {
 		tmp = TAILQ_FIRST(&fc->messages);
 		if (!tmp)
diff --git a/port_private.h b/port_private.h
index 436e7b7..806329d 100644
--- a/port_private.h
+++ b/port_private.h
@@ -108,6 +108,7 @@ struct port {
 	int                 follow_up_info;
 	int                 freq_est_interval;
 	int                 hybrid_e2e;
+	int                 master_only;
 	int                 match_transport_specific;
 	int                 min_neighbor_prop_delay;
 	int                 net_sync_monitor;
diff --git a/ptp4l.8 b/ptp4l.8
index 011bd02..2aee03e 100644
--- a/ptp4l.8
+++ b/ptp4l.8
@@ -245,6 +245,13 @@ The default is UDPv4.
 Upper limit for peer delay in nanoseconds. If the estimated peer delay is
 greater than this value the port is marked as not 802.1AS capable.
 .TP
+.B masterOnly
+Setting this option to one (1) prevents the port from entering the
+SLAVE state. In addition, the local clock will ignore Announce
+messages received on this port. This option's intended use is to
+support the Telecom Profiles according to ITU-T G.8265.1, G.8275.1,
+and G.8275.2. The default value is zero or false.
+.TP
 .B G.8275.portDS.localPriority
 The Telecom Profiles (ITU-T G.8275.1 and G.8275.2) specify an
 alternate Best Master Clock Algorithm (BMCA) with a unique data set