diff --git a/candm.h b/candm.h
index 75425b9..ff17f42 100644
--- a/candm.h
+++ b/candm.h
@@ -672,6 +672,7 @@ typedef struct {
   uint32_t total_tx_count;
   uint32_t total_rx_count;
   uint32_t total_valid_count;
+  uint32_t reserved[4];
   int32_t EOR;
 } RPY_NTPData;
 
diff --git a/cmdmon.c b/cmdmon.c
index cbfcdea..00e9f4e 100644
--- a/cmdmon.c
+++ b/cmdmon.c
@@ -1232,6 +1232,7 @@ handle_ntp_data(CMD_Request *rx_message, CMD_Reply *tx_message)
   tx_message->data.ntp_data.total_tx_count = htonl(report.total_tx_count);
   tx_message->data.ntp_data.total_rx_count = htonl(report.total_rx_count);
   tx_message->data.ntp_data.total_valid_count = htonl(report.total_valid_count);
+  memset(tx_message->data.ntp_data.reserved, 0xff, sizeof (tx_message->data.ntp_data.reserved));
 }
 
 /* ================================================== */