Using External Time Servers - D-Link NetDefendOS User Manual

7. For End Date select October
8. For End Day select 25
9. Click OK

2.2.4. Using External Time Servers

NetDefendOS is able to adjust the system time automatically using information received from
one or more external time servers. These time provide a highly accurate time, usually using
atomic clocks. Using time servers is recommended as it ensures NetDefendOS will have its date
and time aligned with other network devices.
Time Synchronization Protocols
Time Synchronization Protocols are standardized methods for retrieving time information from
external time servers. NetDefendOS supports the following such protocols:
• SNTP
Defined by RFC 2030, The Simple Network Time Protocol (SNTP) is a lightweight
implementation of NTP (RFC 1305). SNTP is used by NetDefendOS to query time servers. Most
public time servers are described as being NTP servers and are accessible using SNTP.
• UDP/TIME
The UDP/TIME protocol is an older method of providing time synchronization service over the
Internet. The server sends back the time in seconds since midnight on January 1st, 1900.
Methods of Configuring Time Servers
NetDefendOS provides the ability to configure one of the following two types of time server:
• The D-Link Time Server
D-Link operates its own time server which can be used instead of publicly available servers.
• Custom Time Servers
Specific time servers can be specified. There are a number of publicly available time servers
that can be configured.
Configuring these two types of server is described next.
Configuring the D-Link Time Server
A single property exists to switch on or off usage of the D-Link time server. This is the easiest way
of configuring a time server since no other server details need to be specified. NetDefendOS will
find the IP address of the time server by performing a DNS lookup of the time server's FQDN.
Note that at least one external DNS server must be configured in NetDefendOS so that the FQDN
of the D-Link's time server can be resolved.
Chapter 2: Management and Maintenance
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