Brocade FastIron Ethernet Switch Security Configuration Guide - Manual (Page 343)

• Before relaying a DHCP discovery packet or DHCP request packet from a client to a DHCP server,
the FastIron switch will add agent information to the packet.
• Before relaying a DHCP reply packet from a DHCP server to a client, the FastIron switch will remove
relay agent information from the packet.
As illustrated in the following figure, the DHCP relay agent (the FastIron switch), inserts DHCP option
82 attributes when relaying a DHCP request packet to a DHCP server.
FIGURE 26 DHCP Option 82 attributes added to the DHCP packet
t
As illustrated in the following figure, the FastIron switch deletes DHCP option 82 attributes before
forwarding a server reply packet back to a DHCP client.
FIGURE 27 DHCP Option 82 attributes removed from the DHCP packet
The DHCP option 82 insertion/deletion feature is available only when DHCP snooping is enabled for the
client/server ports.
Configuration notes for DHCP option 82
• DHCP snooping and DHCP option 82 are supported on a per-VLAN basis.
• DHCP option 82 follows the same configuration rules and limitations as for DHCP snooping. For
more information, refer to Configuration notes and feature limitations for DHCP snooping on page
338.
Configuration notes for DHCP option 82
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