ZyXEL MI-7248 User Guide - Page 198

DHCP Relay

Page 198 highlights

Chapter 35 DHCP Figure 92 DHCP Status The following table describes the labels in this screen. Table 74 DHCP Status LABEL DESCRIPTION Index This is the index number. VID This field displays the ID number of the VLAN group to which this DHCP settings apply. Server Status This field displays the starting DHCP client IP address. IP Pool Size This field displays the size of the DHCP client IP address pool. Relay Mode This field displays: • None - if the switch is not configured as a DHCP relay agent. • Global - if the switch is configured as a DHCP relay agent only. • VLAN - followed by a VLAN ID if it is configured as a relay agent for specific VLAN(s). 35.3 DHCP Relay Configure DHCP relay on the switch if the DHCP clients and the DHCP server are not in the same subnet. During the initial IP address leasing, the switch helps to relay network information (such as the IP address and subnet mask) between a DHCP client and a DHCP server. Once the DHCP client obtains an IP address and can connect to the network, network information renewal is done between the DHCP client and the DHCP server without the help of the switch. The switch can be configured as a global DHCP relay. This means that the switch forwards all DHCP requests from all domains to the same DHCP server. You can also configure the switch to relay DHCP information based on the VLAN membership of the DHCP clients. 35.3.1 DHCP Relay Agent Information The switch can add information about the source of client DHCP requests that it relays to a DHCP server by adding Relay Agent Information. This helps provide authentication about the source of the requests. The DHCP server can then provide an IP address based on this information. Please refer to RFC 3046 for more details. The DHCP Relay Agent Information feature adds an Agent Information field to the Option 82 field. The Option 82 field is in the DHCP headers of client DHCP request frames that the switch relays to a DHCP server. 198 MS-7206 User's Guide

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Chapter 35 DHCP
MS-7206 User’s Guide
198
Figure 92
DHCP Status
The following table describes the labels in this screen.
35.3
DHCP Relay
Configure DHCP relay on the switch if the DHCP clients and the DHCP server are not in the
same subnet. During the initial IP address leasing, the switch helps to relay network
information (such as the IP address and subnet mask) between a DHCP client and a DHCP
server. Once the DHCP client obtains an IP address and can connect to the network, network
information renewal is done between the DHCP client and the DHCP server without the help
of the switch.
The switch can be configured as a global DHCP relay. This means that the switch forwards all
DHCP requests from all domains to the same DHCP server. You can also configure the switch
to relay DHCP information based on the VLAN membership of the DHCP clients.
35.3.1
DHCP Relay Agent Information
The switch can add information about the source of client DHCP requests that it relays to a
DHCP server by adding
Relay Agent Information
. This helps provide authentication about
the source of the requests. The DHCP server can then provide an IP address based on this
information. Please refer to RFC 3046 for more details.
The DHCP
Relay Agent Information
feature adds an Agent Information field to the
Option
82
field. The
Option 82
field is in the DHCP headers of client DHCP request frames that the
switch relays to a DHCP server.
Table 74
DHCP Status
LABEL
DESCRIPTION
Index
This is the index number.
VID
This field displays the ID number of the VLAN group to which this DHCP settings
apply.
Server Status
This field displays the starting DHCP client IP address.
IP Pool Size
This field displays the size of the DHCP client IP address pool.
Relay Mode
This field displays:
None
- if the switch is not configured as a DHCP relay agent.
Global
- if the switch is configured as a DHCP relay agent only.
VLAN
- followed by a VLAN ID if it is configured as a relay agent for specific
VLAN(s).