CLI Reference Guide-R07

Chapter 26 | DHCP Commands (IPv4 and IPv6)
DHCP Relay (IPv4 and IPv6)
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A DHCP relay server has been set on the switch, when the switch receives a
DHCP request packet with a non-zero relay agent address field (that is not
the address of this switch).
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A DHCP relay server has been set on the switch, when the switch receives
DHCP reply packet without option 82 information from the management
VLAN.
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The reply packet contains a valid relay agent address field (that is not the
address of this switch), or receives a reply packet with a zero relay agent
address through the management VLAN.
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A DHCP relay server has been set on the switch, and the switch receives a
reply packet on a non-management VLAN.
◆ Use the ip dhcp relay information option encode no-subtype command to
specify how to handle DHCP client request packets which already contain
Option 82 information.
◆ DHCP Snooping Information Option 82 (see page 293) and DHCP Relay
Information Option 82 cannot both be enabled at the same time.
Example
This example enables Option 82.
Console(config)#ip dhcp relay information option
Console(config)#
Related Commands
ip dhcp relay information policy (642)
ip dhcp relay server (635)
ip dhcp snooping (291)
ip dhcp relay
information option
encode no-subtype
Use this command to disable the inclusion of sub-type and sub-length fields in
circuit-ID (CID) and remote-ID (RID) in Option 82 information. Use the no form of
this command to include the sub-type.
Syntax
[no] ip dhcp relay information option encode no-subtype
Default Setting
Extra Subtype included
Command Mode
Global Configuration