Hello David
First of all, when you issue the set interface command within a route map, you are telling the device what exit interface to use for PBR. However, if the exit interface belongs to a multi-access technology, like Ethernet, there may be multiple possible next hops on that network segment. This is what this particular error message is hinting at. In a P2P technology, such as a serial link, there is only one possible recipient on the other end, and this is why the designation of the exit interface is enough for the purposes of PBR.
Now, the error message is simply a warning, which means the command has been accepted, but it may not function in a predictable manner. As for the ARPing of the 17.8.125.176 address, I’m not quite sure why this particular IP address is being used. Just out of curiosity, I did an IP address lookup for this address and found it to be a static IP in Apple INC’s datacenter in Cupertino California, USA.
Do you have this address configured anywhere on your devices? I assume not. In any case, I can’t shed any more light on why this particular address is being ARPed, but you can resolve the issue by replacing the set interface command with a set ip next-hop command.
I hope this has been helpful!
Laz