Owners manual

DGS-1510 Series Gigabit Ethernet SmartPro Switch CLI Reference Guide
153
In addition to DHCP relay packets, the relay destination of the DHCP server can be specified in the
DHCP relay pool. To do this, use the ip dhcp pool command to enter the DHCP pool configuration, use
the relay source command to specify the source subnet of the client requests, and use the relay
destination command to specify the relay destination server address.
When receiving a DHCP request packet, if the subnet that the packet comes from matches the relay
source of a relay pool, the packet will be relayed based on the matched relay pool. To relay based on the
relay pool, if the request packet is a relayed packet, the Gateway IP Address (GIADDR) of the packet is
the source of the request. If the GIADDR is zero, the subnet of the received interface is the source of the
packet.
In a DHCP relay pool, the user can further use the class command and the relay target command to
define the relay target address for the request packets that match the option pattern.
Example
This example shows how to a DHCP relay pool, called pool1, is created. In the relay pool, the subnet
172.19.18.0/255.255.255.0 is specified as the source subnet. 10.2.1.1 is specified as the relay destination
address.
Switch# configure terminal
Switch(config)# ip dhcp pool pool1
switch(config-dhcp-pool)# relay source 172.19.18.0 255.255.255.0
switch(config-dhcp-pool)# relay destination 10.2.1.1
switch(config-dhcp-pool)#
16-4 ip dhcp relay information check
This command is used to enable the DHCP relay agent to validate and remove the relay agent
information option in the received DHCP reply packet. Use the no form of the command to globally
disable the check for Option 82.
ip dhcp relay information check
no ip dhcp relay information check
Parameters
None.
Default
By default, this option is disabled.
Command Mode
Global Configuration Mode.
Command Default Level
Level: 12.
Usage Guideline
This command takes effect when the DHCP service is enabled.
The ip dhcp relay information check command and the ip dhcp relay information check-reply
command together determine whether the check function of Option 82 is effective for an interface. If the
ip dhcp relay information check-reply command is not configured for an interface, the global setting
takes effect. If the ip dhcp relay information check-reply command is configured for an interface, the
interface setting takes effect.