59
4.2.9 DHCP Relay
Configure DHCP Relay on this Page.
DHCP Relay
is used to forward and to transfer DHCP messages between the clients and the
server when they are not on the same subnet domain.
The
DHCP option 82
enables a DHCP relay agent to insert specific information into a DHCP request packets when forwarding client
DHCP packets to a DHCP server and remove the specific information from a DHCP reply packets when forwarding server DHCP
packets to a DHCP client. The DHCP server can use this information to implement IP address or other assignment policies.
Specifically the option works by setting two sub-options:
Circuit ID (option 1)
Remote ID (option2).
The
Circuit ID
sub-option is supposed to include information specific to which circuit the request came in on.
The
Remote ID
sub-option was designed to carry information relating to the remote host end of the circuit.
The definition of Circuit ID in the switch is 4 bytes in length and the format is "vlan_id" "module_id" "port_no". The parameter of
"vlan_id" is the first two bytes representing the VLAN ID. The parameter of "module_id" is the third byte for the module ID (in
standalone switch it always equals 0; in stackable switch it means switch ID). The parameter of "port_no" is the fourth byte and it
means the port number.
The Remote ID is 6 bytes in length, and the value equals the DHCP relay agent’s MAC address. The DHCP Relay Configuration
screen in
Figure 4-2-12
appears.
Figure 4-2-12
DHCP Relay
Configuration Page Screenshot
The Page includes the following fields:
Object
Description
Relay Mode
Indicates the DHCP relay mode operation. Possible modes are:
Enabled
: Enable DHCP relay mode operation. When enabling DHCP relay
mode operation, the agent forwards and transfers DHCP messages between
the clients and the server when they are not on the same subnet domain.
And the DHCP broadcast message won't flood for security considered.
Disabled
: Disable DHCP relay mode operation.
Содержание NS4702-24P-4S-4X
Страница 1: ...NS4702 24P 4S 4X User Manual P N 1072829 REV 00 01 ISS 14JUL14 ...
Страница 23: ...23 Storage Temperature 10 70 degrees C Relative Humidity 5 95 non condensing ...
Страница 164: ...164 Figure 4 8 2 Multicast Flooding ...
Страница 183: ...183 Figure 4 8 14 IGMP Snooping VLAN Configuration Page Screenshot ...
Страница 189: ...189 Figure 4 8 17 MLD Snooping Groups Information Page Screenshot ...
Страница 203: ...203 Buttons Click to apply changes Click to undo any changes made locally and revert to previously saved values ...
Страница 208: ...208 Figure 4 9 6 QoS Egress Port Tag Remarking Page Screenshot ...
Страница 218: ...218 Deletes the QCE The lowest plus sign adds a new entry at the bottom of the list of QCL ...
Страница 229: ...229 Figure 4 9 18 Voice VLAN Configuration Page Screenshot ...
Страница 252: ...252 Buttons Click to apply changes Click to undo any changes made locally and revert to previously saved values ...
Страница 291: ...291 measurement is 100 ms A value of 0 ms indicates that there hasn t been round trip communication with the server yet ...
Страница 299: ...299 Figure 4 11 17 Add User Properties Screen Figure 4 11 18 Add User Properties Screen ...
Страница 336: ...336 Figure 4 14 2 LLDPMED Configuration Page Screenshot ...
Страница 357: ...357 Figure 4 15 4 VeriPHY Cable Diagnostics Page Screenshot ...
Страница 367: ...367 ...
Страница 375: ...375 Figure 4 16 10 Port Power Consumption Screenshot Buttons Click to refresh the page immediately ...
Страница 391: ...391 ...