99
Parameter
Description
State
Select this option to enable / disable the DHCP option 82 on the
Switch.
Circuit Frame
The frame ID for the circuit sub-option.
Circuit Shelf
The shelf ID for the circuit sub-option.
Circuit Slot
The slot ID for the circuit sub-option.
Circuit-ID String
The String of the circuit ID sub-option information.
Remote-ID String
The String of the remote ID sub-option information.
Apply
Click
Apply
to save your changes to the Switch.
Refresh
Click
Refresh
to begin configuring this screen afresh.
DHCP Option 82 Port Settings
Port
The port ID.
Circuit-ID String
The String of the circuit ID sub-option information for the specific
port.
Remote-ID String
The String of the remote ID sub-option information for the specific
port.
DHCP Option 82 Port Status
The field displays all of the ports’ configurations.
6.5.
DHCP Relay
6.5.1.
Introduction
Because the
DHCPDISCOVER message is a broadcast message,
and broadcasts only cross other
segments when they are explicitly routed, you might have to configure a DHCP Relay Agent on
the router interface so that all DHCPDISCOVER messages can be forwarded to your DHCP
server. Alternatively, you can configure the router to forward DHCP messages and BOOTP
message.
In a routed network, you would need DHCP Relay Agents if you plan to implement only
one DHCP server.
The DHCP Relay that either a host or an IP router that listens for DHCP client messages being
broadcast on a subnet and then forwards those DHCP messages directly to a configured DHCP
server. The DHCP server sends DHCP response messages directly back to the DHCP relay agent,
which then forwards them to the DHCP client. The DHCP administrator uses DHCP relay agents
to centralize DHCP servers, avoiding the need for a DHCP server on each subnet.
Most of the time in small networks DHCP uses broadcasts however there are some circumstances
where unicast addresses will be used. A router for such a subnet receives the DHCP broadcasts,
