diff --git a/test/simulation/105-ntpauth b/test/simulation/105-ntpauth
index 3e88d92..d696446 100755
--- a/test/simulation/105-ntpauth
+++ b/test/simulation/105-ntpauth
@@ -27,7 +27,16 @@ server_conf=""
 
 run_test || test_fail
 check_chronyd_exit || test_fail
-# This check must fail as server doesn't know the key
+# These checks must fail as the server doesn't know the key
 check_sync && test_fail
+check_packet_interval && test_fail
 
+server_conf="keyfile tmp/keys"
+client_conf=""
+
+run_test || test_fail
+check_chronyd_exit || test_fail
+# These checks must fail as the client doesn't know the key
+check_sync && test_fail
+check_packet_interval && test_fail
 test_pass