Fixing Networking Problems with a Cloned Linux VM
Often when cloning virtual Linux boxes (or using VMWare converter to deploy a virtual appliance) I find that the networking simply doesn't work. eth0 will exist but will not find a network even after checking and double checking /etc/networking/interfaces. The problem is that Linux has associated eth0 with the previous machines mac address for that interface.
/etc/udev/rules.d/70-persistent-net.rules (on ubuntu anyway)
This file will contain the associations such as...
# PCI device 0x1022:0x2000 (vmxnet)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:0c:29:36:xx:xx", ATTR{type}=="1", NAME="eth0"
# PCI device 0x1022:0x2000 (vmxnet)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:0c:29:75:xx:xx", ATTR{type}=="1", NAME="eth1"
The first (eth0) will be from the original machine, and the second (currently eth1) is from the new VM.
To Fix
First stop udev and networking...
/etc/init.d/udev stop
/etc/init.d/networking stop
Edit /etc/udev/rules.d/70-persistent-net.rules, remove the original interface and rename the new interface from eth1 to eth0. Restart networking...
/etc/init.d/udev start
/etc/init.d/networking start
All being well, your Linux box should now have networking back 
Hope this help
Chris