D-Link DGS-3630-52PC Quick installation Guide - Page 106

DGS-3630 Series Layer 3 Stackable Managed Switch Web UI Reference Guide The DHCP client will be activated to get the network settings from the DHCP server and the DHCP server includes the TFTP server IP address and image filename with the message. The Switch then receives this information and triggers the TFTP downloading function from the specified TFTP server. At this stage, the system will display the download configuration parameters on the console. The layout is the same as using the download firmware command. After the firmware download was completed, the Switch will then reboot immediately. If both the auto-configuration and auto-image features are enabled at the same time, system will download the image file first and then download the configuration. After this, the Switch will then save the configuration and reboot. The Switch will always check the downloaded firmware. If the version is the same as the current running firmware, the Switch will terminate the auto-image process. The downloaded configuration, however, will still be executed if the auto-configuration feature is also enabled. This function is similar to the auto-configuration function. Both the image file and the configuration file must be placed on the same TFTP server, as the DHCP option fields are not only used in the auto-image feature, but also in the autoconfiguration feature. The TFTP server IP address is still placed in the DHCP siaddr fields Option 66 or Option 150. If Option 66, Option 150 and the siaddr fields exist in the DHCP response message at the same time, the Option 150 will be resolved first. If the system fails to connect to the TFTP server, then the system will resolve the Option 66, and if the system still fails to connect the TFTP server, the siaddr field is the last choice. When the Switch uses Option 66 to get the TFTP server name, it resolves Option 6 first to get the DNS server IP address. If the Switch fails to connect to the DNS server or Option 6 does not exist in the response message, the Switch will try to connect the DNS server already configured in the system manually. Option 67 is used to identify the boot file when the 'file' field in the DHCP header has been used for DHCP options. This can only be used in the DHCP auto-configuration mode and not the DHCP auto-image mode. For more information refer to RFC 2132. When specifying the image file name, the DHCP Option 125 (RFC 3925) must be used. The Switch needs to check the enterprise-number1 field. If the value is not the D-Link vendor ID (171), the Switch will stop the process. If the Option contains more than one field, only the first entry enterprise-number1 will be used. To view the following window, click Management > DHCP Auto Image Settings, as shown below: Figure 4-67 DHCP Auto Image Settings Window The fields that can be configured are described below: Parameter DHCP Auto Image State DHCP Auto Image Timeout Description Select to enable or disable the DHCP auto-image feature here. Enter the timeout value of the DHCP auto-image feature here. The range is from 1 to 65535 seconds. Click the Apply button to accept the changes made. DNS The Domain Name System (DNS) is used to map human-readable domain names to the IP addresses used by computers to communicate. A DNS server performs name-to-address translation, and may need to contact several name servers to translate a domain to an address. The address of the machine that supplies domain name service is often supplied by a DHCP or BOOTP server, or can be entered manually and configured into the operating system at startup. DNS Global Settings This window is used to display and configure the global DNS settings. 94