D-Link DXS-3400 User Manual - Page 80

DXS-3400 Series Lite Layer 3 Stackable 10GbE Managed Switch Web UI Reference Guide Parameter Description Option 18 to the request packets from the client. If the Option 37 check state is enabled, the Switch will check the request packet from the client and drop the packet if it contains Option 37 as specified in the DHCPv6 relay function. If the Option 37 check state is disabled, the local relay function will always add Option 37 to the request packet, regardless whether the state of Option 37 is enabled or disabled. The DHCPv6 local relay function will directly forward the packet from the server to the client after which no more processing is done. Click the Apply button to accept the changes made. DHCP Auto Configuration This window is used to display and configure the DHCP auto-configuration function. To view the following window, click Management>DHCP Auto Configuration, as shown below: Figure 4-59DHCP Auto Configuration Window The fields that can be configured are described below: Parameter Auto Configuration State Description Select this option to enable or disable the auto-configuration function. Click the Apply button to accept the changes made. DNS Computer users usually prefer to use text names for computers for which they may want to open a connection. Computers themselves, require 32 bit IP addresses. Somewhere, a database of network devices' text names and their corresponding IP addresses must be maintained. The Domain Name System (DNS) is used to map names to IP addresses throughout the Internet and has been adapted for use within intranets. For two DNS servers to communicate across different subnets, the DNS Relay of the Switch must be used. The DNS servers are identified by IP addresses. Mapping Domain Names to Addresses Name-to-address translation is performed by a program called a Name server. The client program is called a Name resolver. A Name resolver may need to contact several Name servers to translate a name to an address. The Domain Name System (DNS) servers are organized in a somewhat hierarchical fashion. A single server often holds names for a single network, which is connected to a root DNS server - usually maintained by an ISP. Domain Name Resolution The domain name system can be used by contacting the name servers one at a time, or by asking the domain name system to do the complete name translation. The client makes a query containing the name, the type of answer required, and a code specifying whether the domain name system should do the entire name translation, or simply return the address of the next DNS server if the server receiving the query cannot resolve the name. When a DNS server receives a query, it checks to see if the name is in its sub domain. If it is, the server translates the name and appends the answer to the query, and sends it back to the client. If the DNS server cannot translate the 70