Networking Q concerning /etc/network/interfaces

[Harry Putnam <reader@newsguy.com>]

Running wheezy - 3.0.0-1-686-pae

I'm getting confused by what I see in /etc/network/interfaces,
compared to what I see with ifconfig -a. 

What I see in /etc/network/interfaces:

  auto lo
  iface lo inet loopback
  allow-hotplug eth0
  iface eth0 inet dhcp

Does not match what I see with ifconfig -a

    eth0  Link encap:Ethernet  HWaddr 00:40:f4:b5:29:41  
          inet addr:192.168.1.54  Bcast:192.168.1.255  Mask:255.255.255.0
          BROADCAST MULTICAST  MTU:1500  Metric:1


 [...]

    eth1  Link encap:Ethernet  HWaddr 00:11:09:ee:6c:04  
          inet addr:192.168.1.42  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::211:9ff:feee:6c04/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

[...]

-------        ---------       ---=---       ---------      -------- 

What shows as eth1 in ifconfig is the working IP (...42) of this host.
Nothing is plugged into device seen as eth0 (...54).  That is,
although there is a second network adapter, nothing is plugged into
it, and all traffic comes and goes on [...]42.

It can be seen in the output of netstat -r

  Kernel IP routing table
 Destination Gateway     Genmask         Flags   MSS Window  irtt Iface
 default     fw.local.lan 0.0.0.0         UG        0 0          0 eth1
 192.168.1.0 *            255.255.255.0   U         0 0          0 eth1


So it appears at a superficial reckoning that dhcp has assigned an
address to eth0, but that address appears to be attached to eth1 in
ifconfig and netstat output.

What explains this apparent anomaly?