Edge-Core ECS4210-12P - Page 464

Chapter 15 | IP Services
Dynamic Host Configuration Protocol
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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.
Parameters
These parameters are displayed:
◆ Insertion of Relay Information – Enable DHCP Option 82 information relay.
(Default: Disabled)
◆ DHCP Option Policy – Specifies how to handle client requests which already
contain DHCP Option 82 information:
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Drop - Floods the original request packet onto the VLAN that received it
instead of relaying it. (This is the default.)
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Keep - Retains the Option 82 information in the client request, inserts the
relay agent’s address, and unicasts the packet to the DHCP server.
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Replace - Replaces the Option 82 information circuit-id and remote-id
fields in the client’s request with information provided by the relay agent
itself, inserts the relay agent’s address, and unicasts the packet to the DHCP
server.
◆ DHCP Sub-option Format – Specifies whether or not to use the sub-type and
sub-length fields in the circuit-ID (CID) and remote-ID (RID) in Option 82
information. (Default: Included)
◆ DHCP Remote ID Sub-option – Specifies the format used to identify this
switch as the DHCP relay agent to the DHCP server:
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MAC Address - Includes a MAC address field for the relay agent (that is, the
MAC address of the switch’s CPU). This attribute can be encoded in
hexadecimal or ASCII.
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IP Address - Includes the IP address field for the relay agent (that is, the IP
address of the management interface). This attribute can be encoded in
hexadecimal or ASCII.
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String - An arbitrary string inserted into the remote identifier field.
(Range: 1-32 characters)