Configuring SNTP
24.2.8 Configuring Overtime Retransmist
This Command is effective in unicast and any cast operating mode. SNTP request packet
is UDP packet, overtime retransmission system is adopted because the requirement packet
cannot be guaranteed to send to the destination. Use above Commands to configure
retransmit times and the interval.
Table 24-8 Configure overtime retransmit
Enter globally configuration
mode
configure overtime retransmit
Sntp client
retransmit-interval time
By default, retransmit-interval
seconds is 5s
configure overtime retransmit
times
sntp client retransmit times
By default 0,means do not
retransmit
24.2.9 Configuring Valid Servers
In broadcast and multicast mode, SNTP client receives protocol packets from all servers
without distinction. When there is malice attacking server (it will not provide correct time),
local time cannot be the standard time. To solve this problem, a series of valid servers can be
listed to filtrate source address of the packet.
Table 24-9 Configure valid server
Enter globally configuration
mode
sntp client valid-server IP mask
24.2.10 Configuring MD5 Authentication
To enhance the safety, MD5 authentication can be setup between SNTP sever and SNTP
client which only receives the authenticated message. MD5 authentication configures as
below:
Table 24-10 Configure MD5 authentication
Enter globally configuration
mode
Startup MD5 authentication
Configure authentication keys
sntp client authentication-key
key-number md5 value