ARPDell Networking OS uses two forms of address resolution: address resolution protocol (ARP) and Proxy ARP.ARP runs over Ethernet and enables endstations to learn the MAC addresses of neighbors on an IP network. Over time, DellNetworking OS creates a forwarding table mapping the MAC addresses to their corresponding IP address. This table is called theARP Cache and dynamically learned addresses are removed after a defined period of time.For more information about ARP, refer to RFC 826, An Ethernet Address Resolution Protocol.In Dell Networking OS, Proxy ARP enables hosts with knowledge of the network to accept and forward packets from hosts thatcontain no knowledge of the network. Proxy ARP makes it possible for hosts to be ignorant of the network, including subnetting.For more information about Proxy ARP, refer to RFC 925, Multi-LAN Address Resolution, and RFC 1027, Using ARP to ImplementTransparent Subnet Gateways.Configuration Tasks for ARPFor a complete listing of all ARP-related commands, refer to the Dell Networking OS Command Line Reference Guide.Configuration tasks for ARP include:• Configuring Static ARP Entries (optional)• Enabling Proxy ARP (optional)• Clearing ARP Cache (optional)• ARP Learning via Gratuitous ARP• ARP Learning via ARP Request• Configuring ARP RetriesConfiguring Static ARP EntriesARP dynamically maps the MAC and IP addresses, and while most network host support dynamic mapping, you can configure anARP entry (called a static ARP) for the ARP cache.To configure a static ARP entry, use the following command.• Configure an IP address and MAC address mapping for an interface.CONFIGURATION modearp vrf vrf-name ip-address mac-address interface– vrf vrf-name: use the VRF option to configure a static ARP on that particular VRF.– ip-address: IP address in dotted decimal format (A.B.C.D).– mac-address: MAC address in nnnn.nnnn.nnnn format.– interface: enter the interface type slot/port information.Example of the show arp CommandThese entries do not age and can only be removed manually. To remove a static ARP entry, use the no arp ip-addresscommand.To view the static entries in the ARP cache, use the show arp static command in EXEC privilege mode.Dell#show arpProtocol Address Age(min) Hardware Address Interface VLAN CPU--------------------------------------------------------------------------------324 IPv4 Routing
