PPPOE non-NAT config cannot ping attached hosts as packets go upstream

[neik]

I have a system configured as a plain router for a /29 subnet (no NAT) with an upstream PPPOE link. This means that both the WAN and LAN interfaces have the same IP address. Everything is working fine and has done for years. Except, if I am on the pfSense system I cannot ping a host on the LAN. This is because the packets are sent out of the WAN interface. Note that here the LAN is a network of 6 publically routed IPs.

I tried the "-r" of ping to ignore the routing table. I also note that there seems no way to have ping use a specific interface for sending unicast packets.

This is not just an academic problem: I cannot set up email notifications to a system on the LAN subnet.