1-13 
To do…  Use the command…  Remarks 
Enable NTP authentication 
ntp-service authentication 
enable 
Required 
Disabled by default. 
Configure an NTP 
authentication key 
ntp-service 
authentication-keyid key-id 
authentication-mode md5 
value 
Required 
By default, no NTP 
authentication key is 
configured. 
Configure the specified key as a 
trusted key 
ntp-service reliable 
authentication-keyid key-id 
Required 
By default, no trusted 
authentication key is 
configured. 
Enter VLAN interface view 
interface Vlan-interface vlan-id
— 
Configure on the 
NTP broadcast 
server 
ntp-service broadcast-server 
authentication-keyid key-id 
Associate 
the specified 
key with the 
correspondi
ng 
broadcast/m
ulticast client 
Configure on the 
NTP multicast 
server 
ntp-service multicast-server 
authentication-keyid key-id 
z  In NTP broadcast server 
mode and NTP multicast 
server mode, you need to 
associate the specified 
key with the 
corresponding 
broadcast/multicast client
z  You can associate an 
NTP broadcast/multicast 
client with an 
authentication key while 
configuring NTP mode. 
You can also use this 
command to associate 
them after configuring the 
NTP mode. 
 
 
z  The procedure for configuring NTP authentication on the server is the same as that on the client. 
Besides, the client and the server must be configured with the same authentication key. 
z  In NTP server mode and NTP peer mode, you need to associate the specified key with the 
corresponding NTP server (symmetric-active peer) on the client (symmetric-passive peer). In these 
two modes, multiple NTP servers (symmetric-active peers) may be configured for a client/passive 
peer, and therefore, the authentication key is required to determine which NTP server the local 
clock is synchronized to. 
 
Configuring Optional NTP Parameters 
Complete the following tasks to configure optional NTP parameters: