After it is configured, the system responds to ARP requests on behalf of the device as long as the following conditions are satisfied:
The valid IP ARP request is received on a router interface.
The target IP address matches the IP address configured in the proxy ARP table.
The proxy ARP table entry indicates that the system should answer this ARP request, based on the ingress VLAN (Virtual LAN) and whether the always parameter is set. When the always option is set, the switch always responds to the ARP request even when the ARP requester is on the same subnet as the requested host. If the always option is not set, the switch only answers if the ARP request comes in from a VLAN that is not on the same subnet as the requested host.
When all the proxy ARP conditions are met, the switch formulates an ARP response using one of the following MAC addresses:
A specific MAC address specified with the mac variable.
The VRRP (Virtual Router Redundancy Protocol) virtual MAC address when the vrrp option is specified and the request is received on a VLAN that is running VRRP.
The switch MAC address when neither of the above options applies.
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