Brocade Communications Systems 6650 manual Configuration notes for Dhcp option

DHCP relay agent information

As illustrated in Figure 19, the DHCP relay agent (the Brocade ICX 6650 switch), inserts DHCP option 82 attributes when relaying a DHCP request packet to a DHCP server.

FIGURE 19 DHCP Option 82 attributes added to the DHCP packet

DHCP client

request packet

DHCP

Client

Untrusted

DHCP
Snooping	Trusted
+ option 82

Brocade Switch

DHCP Relay Agent

option

82

DHCP

Server

As illustrated in Figure 20, the Brocade ICX 6650 device deletes DHCP option 82 attributes before forwarding a server reply packet back to a DHCP client.

FIGURE 20 DHCP Option 82 attributes removed from the DHCP packet

Untrusted

DHCP

Client

DHCP

Snooping

option 82

Brocade Switch

DHCP Relay Agent

Trusted

DHCP Server reply packet

option

82

DHCP

Server

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 285.

DHCP option 82 sub-options

The Brocade implementation of DHCP Option 82 supports the following sub-options:

•Sub-Option 1 – Circuit ID

•Sub-Option 2 - Remote ID

•Sub-Option 6 – Subscriber ID

These sub-options are described in the following sections.

Brocade ICX 6650 Security Configuration Guide	289
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