1-12 
Configuring Access-Control Rights 
With the following command, you can configure the NTP service access-control right to the local device. 
There are four access-control rights, as follows: 
z  query: control query permitted. This level of right permits the peer devices to perform control query 
to the NTP service on the local device but does not permit a peer device to synchronize its clock to 
that of the local device. The so-called “control query” refers to query of some states of the NTP 
service, including alarm information, authentication status, clock source information, and so on. 
z  synchronization: server access only. This level of right permits a peer device to synchronize its 
clock to that of the local device but does not permit the peer devices to perform control query. 
z  server: server access and query permitted. This level of right permits the peer devices to perform 
synchronization and control query to the local device but does not permit the local device to 
synchronize its clock to that of a peer device. 
z  peer: full access. This level of right permits the peer devices to perform synchronization and control 
query to the local device and also permits the local device to synchronize its clock to that of a peer 
device. 
From the highest NTP service access-control right to the lowest one are peer,  server, 
synchronization, and query. When a device receives an NTP request, it will perform an 
access-control right match and will use the first matched right. 
Configuration Prerequisites 
Prior to configuring the NTP service access-control right to the local device, you need to create and 
configure an ACL associated with the access-control right. For the configuration of ACL, refer to ACL 
Configuration in the Security Volume. 
Configuration Procedure 
Follow these steps to configure the NTP service access-control right to the local device: 
To do…  Use the command…  Remarks 
Enter system view 
system-view 
— 
Configure the NTP service 
access-control right for a peer 
device to access the local 
device  
ntp-service access { peer | 
query | server | 
synchronization } acl-number
Required 
peer by default 
 
 
The access-control right mechanism provides only a minimum degree of security protection for the 
system running NTP. A more secure method is identity authentication.