ARP: can't create published proxy entry for remote tun(4) address

[Chuck Musser]

Hi,

I'm having trouble creating an "published" ARP cache entry for an 
address
that's on the remote end of a tun(4) interface. The intent is serving as 
a proxy
for a VPN client that's at the other end of the tunnel.

The command:

arp -s 192.168.1.67 auto pub

returns:

cannot intuit interface index and type for 192.168.1.67

I looked at the arp(8) source code and it looks like the set operation
retrieves a routing table entry that doesn't pass some tests.
What it wants is an entry that is of type AF_LINK, isn't a gateway
and is in a list of valid interface types. I printed out the routing
messages sent and received by the set() function and found some
puzzling things (the debug output here is from my debug printfs):

--- SEND
Destination: 192.168.1.67:0
Flags : ANNOUNCE (PROTO2)
--- RECV
Destination: 0.0.0.0:0
Gateway : 184.23.210.1:0
Flags : UP,GATEWAY,DONE,STATIC
sdl_family: 2: fail
flags: 2115: fail
type: 184: fail
cannot intuit interface index and type for 192.168.1.67

The request, I think I understand, but the response, where the
destination is 0.0.0.0, the gateway is the default gateway for
the system I don't get. Anyone know what's going on here, or
how to create these published proxy entries?

Chuck