Dell PowerSwitch S4128F-ON OS10 Enterprise Edition User Guide Release 10.4.3.0 - Page 136

OS10(config-vrf)#ip address dhcp ip address dhcp OS10(config)#interface 2/1/1 OS10(config-2/1/1)#ip vrf forwarding vrf-TEST OS10(config-vrf-TEST)#ip address dhcp . DHCP relay agent A DHCP relay agent relays DHCP messages to and from a remote DHCP server, even if the client and server are on different IP networks. You can configure the IP address of the remote DHCP server. You can configure a device either as a DHCP server or a DHCP relay agent - but not both. If routes are not leaked between VRFs, the DHCP relay agent supports multi-virtual routing and forwarding (VRF) instances. The clientfacing and server-facing interfaces must be in the same VRF. The DHCPv6 relay agent performs the same role as that of a DHCP relay agent, but in an IPv6 network. The DHCP relay agent forwards the DHCPv4/DHCPv6 messages from the configured interface to the DHCPv6 server as a unicast message. The DHCP relay agent then forwards the server's response to the client. When you configure DHCPv6 relay on an interface, you must: • Configure an IPv6 address on the interface. • Ensure that the DHCPv6 server is reachable. Option 82 for security DHCP, as defined by RFC 2131, provides no authentication or security mechanisms. To provide security, the DHCP relay agent supports Option-82 with Circuit ID sub option, which is the printable name of the interface where the client request was received. This option secures all DHCP traffic that goes through a DHCP relay agent, and ensures that communication between the DHCP relay agent and the DHCP server is not compromised. The DHCP relay agent inserts Option 82 before forwarding DHCP packets to the DHCP server. The DHCP server includes Option 82 back in its response to the relay agent. The relay agent uses this information to forward a reply out the interface on which the request was received rather than flooding it on the entire VLAN. However, the relay agent removes Option 82 from its DHCP responses before forwarding the responses to the client. NOTE: Option 82 is supported, but not configurable. Configuring a DHCP relay agent on an non-default VRF instance To configure DHCP relay agent on an interface corresponding to a non-default VRF instance: 1 Enter the INTERFACE CONFIGURATION mode. CONFIGURATION OS10(config)#interface interface-name interface 2/1/1 2 Configure the DHCP relay agent on the interface that is part of the non-default VRF instance. Specify the name of the non-default VRF instance on which you want to run the relay agent. 136 System management