Dhcp Relay - ZyXEL Communications RGS Series User Manual

Object
Snooping Mode
Port Mode Configuration

5.3.10 DHCP Relay

A DHCP relay agent is used to forward and to transfer DHCP messages between the clients and the server
when they are not in the same subnet domain. It stores the incoming interface IP address in the GIADDR field of
the DHCP packet. The DHCP server can use the value of GIADDR field to determine the assigned subnet. For
such condition, please make sure the switch configuration of VLAN interface IP address and PVID (Port VLAN
ID) correctly.
Object
Relay Mode
Relay Server
Relay Information Mode
Indicates the DHCP snooping mode operation. Possible modes are:
Enabled: Enable DHCP snooping mode operation. When DHCP snooping mode
operation is enabled, the DHCP requests messages will be forwarded to trusted ports
and only allow reply packets from trusted ports.
Disabled: Disable DHCP snooping mode operation.
Indicates the DHCP snooping port mode. Possible port modes are:
Trusted: Configures the port as trusted source of the DHCP messages.
Untrusted: Configures the port as untrusted source of the DHCP messages.
Buttons
Click to apply changes.
Click to undo any changes made locally and revert to previously saved values.
Indicates the DHCP relay mode operation.
Possible modes are:
Enabled: Enable DHCP relay mode operation. When DHCP relay mode operation is
enabled, the agent forwards and transfers DHCP messages between the clients and
the server when they are not in the same subnet domain. And the DHCP broadcast
message won't be flooded for security considerations.
Disabled: Disable DHCP relay mode operation.
Indicates the DHCP relay server
Indicates the DHCP relay information mode option operation. The option 82 circuit ID
format as "[vlan_id][module_id][port_no]". The first four characters represent the
VLAN ID, the fifth and sixth characters are the module ID (in standalone device it
always equal 0, in stackable device it means switch ID), and the last two characters
are the port number. For example, "00030108" means the DHCP message receives
form VLAN ID 3, switch ID 1, port No 8. And the option 82 remote ID value is equal the
switch MAC address.
Description
Description
IP address.
51