The default /etc/network/interfaces on my server contains the following:

# The loopback network interface
auto lo
iface lo inet loopback

#Set up eth0 to use static IP
iface eth0 inet static
    address 64.226.251.105
    netmask 255.255.255.0
    network 64.226.251.104
    broadcast 64.226.251.111
    gateway 64.226.251.110

However, when I run ifconfig, it shows this:

root@debian:/etc/network# ifconfig -a
eth0      Link encap:Ethernet  HWaddr 00:11:11:7d:86:5c
          inet addr:192.168.0.18  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::211:11ff:fe7d:865c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:62156 errors:0 dropped:0 overruns:0 frame:0
          TX packets:38967 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:64061370 (61.0 MiB)  TX bytes:4880863 (4.6 MiB)