Local interface address pinged not via loopback?

[Andrew P.]

Hello,

satbsd# ifconfig tun0
tun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1480
         inet 83.237.61.165 --> 83.237.61.1 netmask 0xffffffff
         Opened by PID 74104

satbsd# ping 83.237.61.165
PING 83.237.61.165 (83.237.61.165): 56 data bytes
^C
--- 83.237.61.165 ping statistics ---
2 packets transmitted, 0 packets received, 100% packet loss

satbsd# tail -n1 /var/log/security
Apr 16 02:57:27 satbsd kernel: ipfw:
120 Deny ICMP:8.0 83.237.61.165 83.237.61.165 in via tun0


Why does the packet go through tun0,
not through lo0? I was sure most
IP stacks wouldn't even touch non-
loopback interfaces if the destination
address matched one of a local interface.

Did I miss something?