Chapter 30 DHCP
DHCP Configuration Options
The DHCP configuration on the Switch is divided into Global 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:
•Global: The Switch forwards all DHCP requests to the same DHCP server.
•VLAN: The Switch is configured on a VLAN by VLAN basis. The Switch can be configured to relay DHCP requests to different DHCP servers for clients in different VLAN.
DHCP Relay
Configure DHCP relay on the Switch if the DHCP clients and the DHCP server are not in the same broadcast domain. 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.
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.
Relay Agent Information can include the System Name of the Switch if you select this option. You can change the System Name in Basic Settings > General Setup.
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