System Time
Defining SNTP Authentication
Cisco Small Business 300 Series Managed Switch Administration Guide  55
6
 
• IPv6 Address Type—Select the IPv6 address type (if IPv6 is used). The 
options are
- Link Local—The IPv6 address uniquely identifies hosts on a single 
network link. A link local address has a prefix of FE80, is not routable, and 
can be used for communication only on the local network. Only one link 
local address is supported. If a link local address exists on the interface, 
this entry replaces the address in the configuration. 
- Global—The IPv6 address is a global Unicast IPV6 type that is visible and 
reachable from other networks. 
• Link Local Interface—Select the link local interface (if IPv6 Address Type 
Link Local is selected) from the list. 
• SNTP Server IP Address—Enter the SNTP server IP address. The format 
depends on which address type was selected.
• SNTP Server—Select the name of the SNTP server from a list of well-known 
SNTP servers. If other is chosen, enter name of SNTP server in the adjacent 
field.
• Poll Interval—Select to enable polling of the SNTP server for system time 
information. All SNTP servers that are registered for polling are polled, and 
the clock is selected from the server with the lowest stratum level (distance 
from the reference clock.) that is reachable. The server with the lowest 
stratum is considered to be the primary server. The server with the next 
lowest stratum is a secondary server, and so forth. If the primary server is 
down, the switch polls all servers with the polling setting enabled, and 
selects a new primary server with the lowest stratum.
• Authentication—Select the check box to enable authentication.
• Authentication Key ID—If authentication is enabled, select the value of the 
key ID. (Create the authentication keys using the SNTP Authentication Page.)
STEP  5 Click Apply. The STNP server is added, and you are returned to the main page.
Defining SNTP Authentication 
The SNTP Authentication Page enables configuration of the authentication keys 
that are used when communicating with an SNTP server that requires 
authentication.