General Dhcp Option 82 Requirements And Operation - HP ProCurve 6200yl Multicast And Routing Manual

IP Routing Features
Configuring DHCP Relay
5-80
DHCP relay agent: See Relay Agent.
Forwarding Policy: The Option 82 method the routing switch uses to process
incoming client DHCP requests. For a given inbound DHCP client request, the
forwarding policy determines whether the routing switch will add Option 82
information, replace existing Option 82 information, or leave any existing
information unchanged. The policy also determines whether the routing
switch will forward the client request toward a DHCP server or drop the
request. For a DHCP server response to an Option 82 client request, the routing
switch can optionally perform a validation check to determine whether to
forward or drop the response. Each Option 82 relay agent in the path between
a DHCP client and an Option 82 DHCP server can be configured with a unique
forwarding policy, which enhances DHCP policy control over discrete areas
of a network.
Primary Relay Agent: In the path between a DHCP client and a DHCP server,
the first routing switch (configured to support DHCP operation) that a client
DHCP request encounters in the path from the client to a DHCP server.
Relay Agent: A routing switch that is configured to support DHCP operation.
Remote ID: In Option 82 applications on ProCurve switches, either the MAC
address of a relay agent, or the IP address of a VLAN or subnet configured on
a relay agent. This value is included as a suboption in an Option 82 field that
the relay agent appends to a Client DHCP request before forwarding the
request toward a DHCP server. (For more on Remote ID, refer to "Remote ID"
in the bulleted list on page 5-82.)
Secondary Relay Agent: In the path between a DHCP client and a DHCP
server, any routing switch (configured to support DHCP operation) other than
the primary relay agent.

General DHCP Option 82 Requirements and Operation

Requirements. DHCP Option 82 operation is configured at the global config
level and requires the following:
■ IP routing enabled on the switch
■ DHCP-Relay Option 82 enabled (global command level)
routing switch access to an Option 82 DHCP server on a different subnet
■
than the clients requesting DHCP Option 82 support
■ one IP Helper address configured on each VLAN supporting DHCP clients