ifconfig.sh should check to see what is already configured and only add a address
if it does not yet exist.

penguin ended up with interfaces configured like this:

lo:0      Link encap:Local Loopback  
          inet addr:10.53.0.1  Mask:255.255.255.255
          UP LOOPBACK RUNNING  MTU:65536  Metric:1

lo:1      Link encap:Local Loopback  
          inet addr:10.53.0.1  Mask:255.255.255.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1

lo:2      Link encap:Local Loopback  
          inet addr:10.53.0.2  Mask:255.255.255.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1

lo:3      Link encap:Local Loopback  
          inet addr:10.53.0.3  Mask:255.255.255.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1

lo:4      Link encap:Local Loopback  
          inet addr:10.53.0.4  Mask:255.255.255.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1

lo:5      Link encap:Local Loopback  
          inet addr:10.53.0.5  Mask:255.255.255.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1

lo:6      Link encap:Local Loopback  
          inet addr:10.53.0.6  Mask:255.255.255.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1

lo:7      Link encap:Local Loopback  
          inet addr:10.53.0.7  Mask:255.255.255.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1

lo:8      Link encap:Local Loopback  
          inet addr:10.53.0.8  Mask:255.255.255.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1

lo:9      Link encap:Local Loopback  
          inet addr:10.53.2.1  Mask:255.255.255.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1

lo:10     Link encap:Local Loopback  
          inet addr:10.53.1.1  Mask:255.255.255.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1