D-Link DFL-260E User Manual for DFL-260E - Page 155
Important: DNS servers need to be con d in NetDefendOS, Time Synchronization Protocols
View all D-Link DFL-260E manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 155 highlights
3.9.3. Time Servers Chapter 3. Fundamentals The hardware clock which NetDefendOS uses can sometimes become fast or slow after a period of operation. This is normal behavior in most network and computer equipment and is solved by utilizing Time Servers. NetDefendOS is able to adjust the clock automatically based on information received from one or more Time Servers which provide a highly accurate time, usually using atomic clocks. Using Time Servers is highly 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 time synchronization protocols: • SNTP Defined by RFC 2030, The Simple Network Time Protocol (SNTP) is a lightweight implementation of NTP (RFC 1305). This is used by NetDefendOS to query NTP servers. • UDP/TIME The Time Protocol (UDP/TIME) is an older method of providing time synchronization service over the Internet. The protocol provides a site-independent, machine-readable date and time. The server sends back the time in seconds since midnight on January first, 1900. Most public Time Servers run the NTP protocol and are accessible using SNTP. Configuring Time Servers Up to three Time Servers can be configured to query for time information. By using more than a single server, situations where an unreachable server causes the time synchronization process to fail can be prevented. NetDefendOS always queries all configured Time Servers and then computes an average time based on all responses. Internet search engines can be used to list publicly available Time Servers. Important: DNS servers need to be configured in NetDefendOS Make sure at least one external DNS server is correctly configured in NetDefendOS so that Time Server URLs can be resolved (see Section 3.10, "DNS"). This is not needed if using IP addresses for the servers. Example 3.27. Enabling Time Synchronization using SNTP In this example, time synchronization is set up to use the SNTP protocol to communicate with the NTP servers at the Swedish National Laboratory for Time and Frequency. The NTP server URLs are ntp1.sp.se and ntp2.sp.se. Command-Line Interface gw-world:/> set DateTime TimeSynchronization=custom TimeSyncServer1=dns:ntp1.sp.se TimeSyncServer2=dns:ntp2.sp.se TimeSyncInterval=86400 Web Interface 1. Go to: System > Date and Time 2. Check the Enable time synchronization 155