Example of Option 82 configuration

In the routing switch shown below, option 82 has been configured with mgmt-vlan for the remote ID.

switch(config)# dhcp-relay option 82 append mgmt-vlan

The resulting effect on DHCP operation for clients X, Y, and Z is shown in the following table.

Figure 11: DHCP Option 82 when using the management VLAN as the remote ID suboption
Table 9: DHCP operation for the topology in DHCP Option 82 when using the management VLAN as the remote ID suboption

Client

Remote ID

giaddr

DHCP server

 

X

10.38.10.1

10.39.10.1

A only

If a DHCP client is in the management VLAN, its DHCP requests can go only to a DHCP server that is also in the management VLAN. Routing to other VLANs is not allowed.

Y

10.38.10.1

10.29.10.1

B or C

Clients outside of the management VLAN can send DHCP requests only to DHCP servers outside of the management VLAN. Routing to the management VLAN is not allowed.

Z

10.38.10.1

10.15.10.1

B or C