diff --git a/unicast_service.c b/unicast_service.c
index 9c9b95b..c6c17c6 100644
--- a/unicast_service.c
+++ b/unicast_service.c
@@ -31,6 +31,9 @@
 #include "unicast_service.h"
 #include "util.h"
 
+#define MIN_LOG_INTER_MESSAGE_PERIOD -7
+#define MAX_LOG_INTER_MESSAGE_PERIOD 16
+#define MAX_DURATION 3600
 #define QUEUE_LEN 16
 
 struct unicast_client_address {
@@ -289,6 +292,15 @@ int unicast_service_add(struct port *p, struct ptp_message *m,
 		return SERVICE_DENIED;
 	}
 
+	if (req->logInterMessagePeriod < MIN_LOG_INTER_MESSAGE_PERIOD ||
+	    req->logInterMessagePeriod > MAX_LOG_INTER_MESSAGE_PERIOD) {
+		return SERVICE_DENIED;
+	}
+
+	if (req->durationField > MAX_DURATION) {
+		req->durationField = MAX_DURATION;
+	}
+
 	LIST_FOREACH(itmp, &p->unicast_service->intervals, list) {
 		/*
 		 * Remember the interval of interest.