DGS-3700-12/DGS-3700-12G Series Layer 2 Gigabit Ethernet Switch User Manual
154
DHCP Screening Port Settings
The Switch supports DHCP Server Screening, a feature that denies acces s to rogue DHCP servers.
When the DHCP server filter function is enabled, all DHCP server pack ets will be filtered from a specific port.
To view this window, click Security > DHCP Server Screening > DHCP Screening Port Settings as shown below:
Figure 5 - 12 DHCP Screening Port Settings window
The following parameters can be set:
Parameter Description
From Port / To Port A consecutive group of ports may be configured starting with the selected port.
State Choose Enabled to enable the DHCP server or Disabled to disable. The default is D isabled.
After setting the previous parameters, click Apply to allow your changes to be im plemented. The DHCP Port
Information Table shows which ports are enabled or disabled for DHCP Sever Screening.
DHCP Offer Filtering
This function allows the user not only to restrict all DHCP Server packets but also to rece ive any specified DHCP
server packet by any specified DHCP client, it is useful when one or m ore DHCP serv ers are pr esent on the net work
and both provide DHCP services to different distinct groups of clients. The first time the DHCP filter is enab led it will
create both an access profile entry and an access rule per p ort entry, it will also create other access rules. Thes e rules
are used to block all DHCP server packets. In addition to a permit DHCP entry, it will also create one acces s profile
and one access rule entry the first time the DHCP client MAC ad dres s is us e d as the c lient MAC address. The Source
IP address is the same as the DHCP server’s IP address (UDP source port number 67). These r ules are used to
permit the DHCP server packets with specific fields, which the user has conf igured.
To view this window, click Security > DHCP Se rver Screening > DHCP Offer Filtering as shown below:
Figure 5 - 13 DHCP Offer Filtering window
The user may set the following parameters:
Parameter Description
Server IP Address The IP address of the DHCP server.