Orion A10E - Default Configurations of DHCP Option; Preparing for Configurations

Orion Networks
A10E/A28E/A28F Configuration Guide
3 IP services
Orion Networks
94
Options
Description
255
Complete option
Options 18, 61, and 82 in DHCP Option are relay agent information options in DHCP packets.
When request packets from DHCP client arrive DHCP server, if need DHCP relay or DHCP
snooping, DHCP relay or DHCP snooping increase Option field into request packets.
Options 18, 61, and 82 implement record DHCP client information on DHCP server. By
cooperating with other software, it can realize IP address distribution restriction and
accounting, etc. functions. Such as cooperate with IP Source Guard to defend deceive of IP
address+MAC address.
Option 82 can include at most 255 sub-options. If defined field Option 82, at least one sub-
option must be defined. The device supports two sub-option types currently: Sub-Option 1
(Circuit ID) and Sub-Option 2 (Remote ID).

Sub-Option 1 contains interface ID of DHCP client request packet, interface VLAN and
the additional information.

Sub-Option 2 is interface MAC address (DHCP relay) or device bridge MAC address
(DHCP snooping device) for receiving DHCP client request packets.
3.7.2 Preparing for configurations
Scenario
DHCP options 61, 82 are relay proxy information options in DHCP packet. When DHCP
Client sends request packet to DHCP Server, DHCP snooping or DHCP relay will add Option
field into request packet if it requires for DHCP snooping or DHCP relay.
DHCP Option 61, 82 fields are used to record DHCP client over IPv4. DHCP server
cooperates with other software to implement functions such as IP address distribution
restriction and accounting based on these information.
Prerequisite
N/A
3.7.3 Default configurations of DHCP Option
The default configuration of DHCP Option is as below.
Function
Default value
attach-string in global configuration mode
Null
remote-id in global configuration mode
switch-mac
circuit-id in interface configuration mode
Null