Dell PowerSwitch S4112F-ON OS10 Enterprise Edition User Guide Release 10.4.1.0 - Page 492
DHCP relay agent, Option 82 for security
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With a fixed host configuration, also known as manual binding, you must configure a network pool with a matching subnet. The static hostto-MAC address mapping pool inherits the network mask from the network pool with subnet configuration, which includes the host's address range. Consider the following example: OS10# show running-configuration interface ethernet 1/1/2 ! interface ethernet1/1/2 no shutdown no switchport ip address 100.1.1.1/24 flowcontrol receive off OS10# show running-configuration ip dhcp ! ip dhcp server no disable ! pool host1 host 100.1.1.34 hardware-address 00:0c:29:ee:4c:f4 ! pool hostnetwork lease infinite network 100.1.1.0/24 ! pool host2 host 20.1.1.34 hardware-address 00:0c:29:aa:22:f4 In this example, the pool host1, which is the fixed host mapping pool, inherits the subnet and other attributes from the pool hostnetwork, which is the DHCP client IP address pool. There is no matching network pool for host2. Therefore, the DHCP client with the MAC address 00:0c:29:aa:22:f4 does not obtain the correct parameters. 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. The DHCP relay agent supports multi-virtual routing and forwarding (VRF) instances. The client-facing 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. 492 System management