In my setup, I do a tap connect which creates a tap interface in vpp and exposes a tap interface in linux user space. The linux user space interface has an ip address of 10.11.12.2/24 with a gateway of 10.11.12.1. The tap interface in vpp space doesn't have an ip but it is enabled for proxy arp reply, and the is a proxy arp range entry for 10.11.12.1 - 10.11.12.255 in place. But, the tap interface in vpp space doesn't reply for an arp in this range. This same setup used to work before in 17.01 or older. Attaching wireshark traces for help.