diff --git a/config.c b/config.c
index a018066..2321310 100644
--- a/config.c
+++ b/config.c
@@ -240,6 +240,7 @@ struct config_item config_tab[] = {
 	GLOB_ITEM_INT("gmCapable", 1, 0, 1),
 	GLOB_ITEM_ENU("hwts_filter", HWTS_FILTER_NORMAL, hwts_filter_enu),
 	PORT_ITEM_INT("hybrid_e2e", 0, 0, 1),
+	PORT_ITEM_INT("ignore_source_id", 0, 0, 1),
 	PORT_ITEM_INT("ignore_transport_specific", 0, 0, 1),
 	PORT_ITEM_INT("ingressLatency", 0, INT_MIN, INT_MAX),
 	PORT_ITEM_INT("inhibit_announce", 0, 0, 1),
diff --git a/configs/default.cfg b/configs/default.cfg
index b791ea3..3ee3a9b 100644
--- a/configs/default.cfg
+++ b/configs/default.cfg
@@ -35,6 +35,7 @@ G.8275.portDS.localPriority	128
 asCapable               auto
 BMCA                    ptp
 inhibit_announce        0
+ignore_source_id        0
 #
 # Run time options
 #
diff --git a/port.c b/port.c
index bf6860c..3e61179 100644
--- a/port.c
+++ b/port.c
@@ -1593,6 +1593,7 @@ int port_initialize(struct port *p)
 	p->peerMeanPathDelay       = 0;
 	p->logAnnounceInterval     = config_get_int(cfg, p->name, "logAnnounceInterval");
 	p->inhibit_announce        = config_get_int(cfg, p->name, "inhibit_announce");
+	p->ignore_source_id        = config_get_int(cfg, p->name, "ignore_source_id");
 	p->announceReceiptTimeout  = config_get_int(cfg, p->name, "announceReceiptTimeout");
 	p->syncReceiptTimeout      = config_get_int(cfg, p->name, "syncReceiptTimeout");
 	p->transportSpecific       = config_get_int(cfg, p->name, "transportSpecific");
@@ -1877,10 +1878,20 @@ void process_delay_resp(struct port *p, struct ptp_message *m)
 	port_set_delay_tmo(p);
 }
 
+static int check_source_identity(struct port *p, struct ptp_message *m)
+{
+	struct PortIdentity master;
+
+	if (p->ignore_source_id) {
+		return 0;
+	}
+	master = clock_parent_identity(p->clock);
+	return pid_eq(&master, &m->header.sourcePortIdentity) ? 0 : -1;
+}
+
 void process_follow_up(struct port *p, struct ptp_message *m)
 {
 	enum syfu_event event;
-	struct PortIdentity master;
 	switch (p->state) {
 	case PS_INITIALIZING:
 	case PS_FAULTY:
@@ -1895,8 +1906,8 @@ void process_follow_up(struct port *p, struct ptp_message *m)
 	case PS_SLAVE:
 		break;
 	}
-	master = clock_parent_identity(p->clock);
-	if (!pid_eq(&master, &m->header.sourcePortIdentity)) {
+
+	if (check_source_identity(p, m)) {
 		return;
 	}
 
@@ -2185,7 +2196,6 @@ void process_pdelay_resp_fup(struct port *p, struct ptp_message *m)
 void process_sync(struct port *p, struct ptp_message *m)
 {
 	enum syfu_event event;
-	struct PortIdentity master;
 	switch (p->state) {
 	case PS_INITIALIZING:
 	case PS_FAULTY:
@@ -2200,8 +2210,8 @@ void process_sync(struct port *p, struct ptp_message *m)
 	case PS_SLAVE:
 		break;
 	}
-	master = clock_parent_identity(p->clock);
-	if (!pid_eq(&master, &m->header.sourcePortIdentity)) {
+
+	if (check_source_identity(p, m)) {
 		return;
 	}
 
diff --git a/port_private.h b/port_private.h
index ca3c906..593eb76 100644
--- a/port_private.h
+++ b/port_private.h
@@ -99,6 +99,7 @@ struct port {
 					 enum fsm_event event, int mdiff);
 	int bmca;
 	int inhibit_announce;
+	int ignore_source_id;
 	/* portDS */
 	struct PortIdentity portIdentity;
 	enum port_state     state; /*portState*/
diff --git a/ptp4l.8 b/ptp4l.8
index d4133a8..99b085c 100644
--- a/ptp4l.8
+++ b/ptp4l.8
@@ -709,6 +709,12 @@ by the Automotive profile as part of switching over to a static BMCA. if this
 option is enabled, ignore_source_id has to be enabled in the slave because it
 has no way to identify master identity in Sync and Follow_Up messages. The
 default is 0 (disabled).
+.TP
+.B ignore_source_id
+This will disable source port identity checking for Sync and Follow_Up
+messages. This is useful when the announce messages are disabled in the master
+and the slave does not have any way to know it's identity. The default is 0
+(disabled).
 
 .SH UNICAST DISCOVERY OPTIONS