diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index ce53f92..7df30f0 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -1416,35 +1416,43 @@
 
     switch (opt.dummy_ticket % 11) {
         case 1:
+            /* Callback function return INVALID_MAC */
             return MBEDTLS_ERR_SSL_INVALID_MAC;
         case 2:
+            /* Callback function return ticket expired */
             return MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED;
         case 3:
+            /* Built-in check, the start time is in future. */
             session->start = mbedtls_ms_time() + 10 * 1000;
             break;
         case 4:
+            /* Built-in check, ticket expired due to too old. */
             session->start = mbedtls_ms_time() - 10 * 1000 - 7 * 24 * 3600 * 1000;
             break;
         case 5:
+            /* Built-in check, age outside tolerance window, too young. */
             session->start = mbedtls_ms_time() - 10 * 1000;
             break;
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
         case 6:
+            /* Built-in check, age outside tolerance window, too old. */
             session->start = mbedtls_ms_time();
-#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
             session->ticket_age_add -= 1000;
-#endif
             break;
-#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
         case 7:
+            /* Built-in check, ticket permission check. */
             session->ticket_flags = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_NONE;
             break;
         case 8:
+            /* Built-in check, ticket permission check. */
             session->ticket_flags = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK;
             break;
         case 9:
+            /* Built-in check, ticket permission check. */
             session->ticket_flags = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL;
             break;
         case 10:
+            /* Built-in check, ticket permission check. */
             session->ticket_flags = MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL;
             break;
 #endif