Chapter 53 DHCP
GS1920v2 Series User’s Guide
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CHAPTER 53
DHCP
53.1  DHCP Overview
This chapter shows you how to configure the DHCP feature.
DHCP (Dynamic Host Configuration Protocol RFC 2131 and RFC 2132) allows individual computers to 
obtain TCP/IP configuration at start-up from a server. If you configure the Switch as a DHCP relay agent, 
then the Switch forwards DHCP requests to DHCP server on your network. If you do not configure the 
Switch as a DHCP relay agent then you must have a DHCP server in the broadcast domain of the client 
computers or else the client computers must be configured manually.
53.1.1  What You Can Do
• Use the DHCPv4 Relay Status screen (Section 53.2 on page 328) to display the relay mode and status.
• Use the DHCPv4 Option 82 Profile screen (Section 53.4 on page 329) to create DHCPv4 option 82 
profiles.
• Use the DHCPv4 Smart Relay screen (Section 53.5 on page 331) to configure global DHCPv4 relay. 
You can also use this screen to apply different DHCP option 82 profile to certain ports on the Switch.
• Use the DHCPv4 Relay VLAN Setting screen (Section 53.6 on page 335) to configure your DHCPv4 
settings based on the VLAN domain of the DHCPv4 clients. You can also use this screen to apply a 
different DHCP option 82 profile to certain ports in a VLAN.
• Use the DHCPv6 Relay screen (Section 53.7 on page 338) to enable and configure DHCPv6 relay.
53.1.2  What You Need to Know
Read on for concepts on DHCP that can help you configure the screens in this chapter.
DHCP Modes
If there is already a DHCP server on your network, then you can configure the Switch as a DHCP relay 
agent. When the Switch receives a request from a computer on your network, it contacts the DHCP 
server for the necessary IP information, and then relays the assigned information back to the computer.
DHCPv4 Configuration Options
The DHCPv4 configuration on the Switch is divided into Smart Relay and VLAN screens. The screen you 
should use for configuration depends on the DHCP services you want to offer the DHCP clients on your 
network. Choose the configuration screen based on the following criteria:
• Smart Relay 
– The Switch forwards all DHCP requests to the same DHCP server.