D-Link DGS-3627G Product Manual - Page 262

xStack® DGS-3600 Series Layer 3 Managed Gigabit Ethernet Switch Filter DHCP Server The Dynamic Host Configuration Protocol (DHCP) automates the assignment of IP addresses, subnet masks, default routers, and other IP parameters. The assignment usually occurs when the DHCP configured machine boots up or regains connectivity to the network. The DHCP client sends out a query requesting a response from a DHCP server on the locally attached network. The DHCP server then replies to the client with its assigned IP address, subnet mask, DNS server and default gateway information. This function allows DHCP server packets except those that have been IP/client MAC bound to be filtered. The Filter DHCP Server is used to configure the state of the function for filtering of DHCP server packets and to add or delete the DHCP server/client binding entry. This command has two purposes firstly to filter all DHCP server packets on the specified port(s) and secondly to allow some DHCP server packets to be forwarded if they are on the pre-defined server IP address/MAC address binding list. Thus the DHCP server can be restricted to service a specified DHCP client. This is useful when there are two or more DHCP servers present on a network. Filter DHCP Server Global Settings This window is used to enable the settings for the Filter DHCP Server Global Settings on the Switch. To view this table, click L3 Features > Filter DHCP Server > Filter DHCP Server Global Settings, as shown below: Figure 4- 95. DHCP Server Filter Global Settings window The following parameters may be configured. Parameter Description Trap/Log To enable or disable the function for filtering DHCP server packets. Illegal Server Log Suppress Duration The DHCP server filtering function filters any illegal DHCP server packets. The DHCP server which sends the illegal packets will be logged. This command is used to suppress the logging of DHCP servers that continue to send illegal DHCP packets. The same illegal DHCP server IP address that is detected will be logged only once regardless of how many illegal packets are sent. The log can be suppressed by 1, 5 or 30 minutes. The default value is 5 minutes. Click Apply to implement the changes. Filter DHCP Server Port Settings This window is used to enable the settings for the Filter DHCP Server Port Settings. To view this window, click L3 Features > Filter DHCP Server > Filter DHCP Server Port Settings, as shown below: 246