diff --git a/config.c b/config.c
index d48e4c0..3be21b7 100644
--- a/config.c
+++ b/config.c
@@ -189,6 +189,10 @@ static void scan_global_line(const char *s, struct config *cfg)
 
 		dds->clockQuality.offsetScaledLogVariance = u16;
 
+	} else if (1 == sscanf(s, " free_running %d", &val)) {
+
+		dds->free_running = val ? 1 : 0;
+
 	} else if (1 == sscanf(s, " assume_two_step %u", &val)) {
 
 		*cfg->assume_two_step = val ? 1 : 0;
diff --git a/default.cfg b/default.cfg
index 857ffd8..fd589e8 100644
--- a/default.cfg
+++ b/default.cfg
@@ -10,6 +10,7 @@ domainNumber		0
 clockClass		248
 clockAccuracy		0xFE
 offsetScaledLogVariance	0xFFFF
+free_running		0
 #
 # Port Data Set
 #
diff --git a/ds.h b/ds.h
index 4be97cb..75a5f84 100644
--- a/ds.h
+++ b/ds.h
@@ -33,6 +33,7 @@ struct defaultDS {
 	UInteger8            priority2;
 	struct ClockIdentity clockIdentity;
 	UInteger8            domainNumber;
+	int                  free_running;
 };
 
 struct dataset {
diff --git a/gPTP.cfg b/gPTP.cfg
index 513816a..947992b 100644
--- a/gPTP.cfg
+++ b/gPTP.cfg
@@ -10,6 +10,7 @@ domainNumber		0
 clockClass		248
 clockAccuracy		0xFE
 offsetScaledLogVariance	0xFFFF
+free_running		0
 #
 # Port Data Set
 #