diff --git a/clock.c b/clock.c
index 14f35232..0c283a61 100644
--- a/clock.c
+++ b/clock.c
@@ -1615,6 +1615,7 @@ int clock_manage(struct clock *c, struct port *p, struct ptp_message *msg)
 {
 	int changed = 0, res, answers;
 	struct port *piter;
+	struct tlv_extra *extra;
 	struct management_tlv *mgt;
 	struct ClockIdentity *tcid, wildcard = {
 		{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}
@@ -1628,7 +1629,15 @@ int clock_manage(struct clock *c, struct port *p, struct ptp_message *msg)
 	if (!cid_eq(tcid, &wildcard) && !cid_eq(tcid, &c->dds.clockIdentity)) {
 		return changed;
 	}
-	if (msg_tlv_count(msg) != 1) {
+	switch (msg_tlv_count(msg)) {
+	case 1:
+		break;
+	case 2:
+		extra = TAILQ_LAST(&msg->tlv_list, tlv_list);
+		if (extra->tlv->type == TLV_AUTHENTICATION) {
+			break;
+		}
+	default:
 		return changed;
 	}
 	mgt = (struct management_tlv *) msg->management.suffix;
diff --git a/pmc.c b/pmc.c
index 6cdd7b03..c50d46f4 100644
--- a/pmc.c
+++ b/pmc.c
@@ -199,7 +199,15 @@ static void pmc_show(struct ptp_message *msg, FILE *fp)
 	fprintf(fp, "\t%s seq %hu %s ",
 		pid2str(&msg->header.sourcePortIdentity),
 		msg->header.sequenceId, pmc_action_string(action));
-	if (msg_tlv_count(msg) != 1) {
+	switch (msg_tlv_count(msg)) {
+	case 1:
+		break;
+	case 2:
+		extra = TAILQ_LAST(&msg->tlv_list, tlv_list);
+		if (extra->tlv->type == TLV_AUTHENTICATION) {
+			break;
+		}
+	default:
 		goto out;
 	}
 	extra = TAILQ_FIRST(&msg->tlv_list);
diff --git a/pmc_agent.c b/pmc_agent.c
index fec6dea7..b6ed996a 100644
--- a/pmc_agent.c
+++ b/pmc_agent.c
@@ -72,14 +72,24 @@ static int check_clock_identity(struct pmc_agent *node, struct ptp_message *msg)
 
 static int is_msg_mgt(struct ptp_message *msg)
 {
+	struct tlv_extra *extra;
 	struct TLV *tlv;
 
 	if (msg_type(msg) != MANAGEMENT)
 		return 0;
 	if (management_action(msg) != RESPONSE)
 		return 0;
-	if (msg_tlv_count(msg) != 1)
+	switch (msg_tlv_count(msg)) {
+	case 1:
+		break;
+	case 2:
+		extra = TAILQ_LAST(&msg->tlv_list, tlv_list);
+		if (extra->tlv->type == TLV_AUTHENTICATION) {
+			break;
+		}
+	default:
 		return 0;
+	}
 	tlv = (struct TLV *) msg->management.suffix;
 	if (tlv->type == TLV_MANAGEMENT)
 		return 1;