Product guide

IP Routing Features
Configuring DHCP Relay
Configuring Option 82 Operation on the Routing Switch
Syntax: dhcp-relay option 82 < append [validate] | replace [validate] | drop [validate]
| keep > [ip | mac]
append: Configures the routing switch to append an Option
82 field to the client DHCP packet. If the client packet
has any existing Option 82 field(s) assigned by
another device, then the new field is appended to the
existing field(s).
The appended Option 82 field includes the switch
Circuit ID (inbound port number*) associated with
the client DHCP packet, and the switch Remote ID. The
default switch remote ID is the MAC address of the
switch on which the packet was received from the
client. To use the incoming VLAN’s IP address instead
of the switch MAC address for the remote ID, use the
ip option (below).
replace: Configures the routing switch to replace any
existing Option 82 field(s) in an inbound client DHCP
packet with one Option 82 field for the current routing
switch.
The replacement Option 82 field includes the switch
circuit ID (inbound port number*) associated with the
client DHCP packet, and the switch remote ID. The
default switch remote ID is the MAC address of the
switch on which the packet was received from the
client. To use the incoming VLAN’s IP address instead
of the switch MAC address for the remote ID, use the
ip option (below).
drop: Configures the routing switch to unconditionally
drop any client DHCP packet received with existing
Option 82 field(s). This means that such packets will
not be forwarded. Use this option where access to the
routing switch by untrusted clients is possible.
If the routing switch receives a client DHCP packet
without an Option 82 field, it adds an Option 82 field
to the client and forwards the packet. The added Option
82 field includes the switch circuit ID (inbound port
number*) associated with the client DHCP packet, and
the switch remote ID. The default switch remote ID is
the MAC address of the switch on which the packet was
received from the client. To use the incoming VLAN’s
IP address instead of the switch MAC address for the
remote ID, use the IP option (below).
11-88