Dell Force10 S55T S55 Configuration Guide FTOS 8.3.5.3 - Page 243

To view the ip helper-address configuration for an interface, use the command show ip interface from EXEC privilege mode, as shown in the following example. R1_E600#show ip int gig 1/3 GigabitEthernet 1/3 is up, line protocol is down Internet address is 10.11.0.1/24 Broadcast address is 10.11.0.255 Address determined by user input IP MTU is 1500 bytes Helper address is 192.168.0.1 192.168.0.2 Directed broadcast forwarding is disabled Proxy ARP is enabled Split Horizon is enabled Poison Reverse is disabled ICMP redirects are not sent ICMP unreachables are not sent Configure the System for User Port Stacking When you set the DHCP offer on the DHCP server, you can set the stacking-option variable to provide the stack-port detail so a stack can be formed when the units are connected. Configure Secure DHCP The following feature is available on platforms: Ze and z except where noted. DHCP as defined by RFC 2131 provides no authentication or security mechanisms. Secure DHCP is a suite of features that protects networks that use dynamic address allocation from spoofing and attacks. • Option 82 • DHCP Snooping • Dynamic ARP Inspection • Source Address Validation Option 82 RFC 3046 (Relay Agent Information option, or Option 82) is used for class-based IP address assignment. The code for the Relay Agent Information option is 82, and is comprised of two sub-options, Circuit ID and Remote ID. • Circuit ID is the interface on which the client-originated message is received. • Remote ID identifies the host from which the message is received. The value of this sub-option is the MAC address of the switch. On the S4810, S55, and S60, the Remote ID can also be the hostname of the switch or an arbitrary string. Dynamic Host Configuration Protocol (DHCP) | 243