System Time Options
System time can be set manually by the user, dynamically by using an SNTP server, or synchronized from the pc running the GUI. If an SNTP server is chosen, the manual time settings are overwritten when communications with the server is established.
As part of the boot process, the switch always configures the time, time-zone, and DST in some way. From DHCP, from the pc running the GUI, from SNTP, from values set manually, or if all else fails from the factory defaults.
Time
The following methods are available for obtaining or setting the time on the switch:
- SNTP--Time can be received from time servers. SNTP that ensures accurate network time synchronization of the switch up to the millisecond by using an SNTP server for the clock source.
NOTE This method is recommended for the sake of accuracy.
- Manual--The user can manually set the time.
- From Browser--Time can be received from the time of the PC using browser information. If this feature is enabled, the switch uses the system time from the configuring computer, unless the time has been configured on the switch manually by the user or SNTP server support is not available or enabled.
After the time has been set by any of the three time sources, it is not set again by the browser.
The configuration of time from browser is saved to the Running Configuration file. You must copy the Running Configuration to the Startup Configuration in order to enable the device to use the time from browser after reboot. The time after reboot is set during the first WEB login to the device.
When the user applies this feature for the first time, if the time was not already set, the device sets the time from the browser.
The time from browser works with both HTTP and HTTPS connections.
NOTE Receiving the time from the computer configuring the switch should be the last resort, such as after a power outage when no other time source is available.
Time Zone and Daylight Savings Time (DST)
The Time Zone and DST can be set on the switch in the following ways:
- Dynamic configuration of the switch through a DHCP server, where:
- Dynamic DST, when enabled and available, always takes precedence over the manual configuration of DST.
- If the server supplying the source parameters fails, or dynamic configuration is disabled by the user, the manual settings are used.
- Dynamic configuration of the time zone and DST continues after the IP address lease time has expired.
- Manual configuration of the time zone and DST by the user, where the time zone and DST set manually becomes the Operational time zone and DST, only if the dynamic configuration of the time zone and DST is disabled or fails.