Virtualisation is not only great in production environment but also the best way when it comes to development.
One of the most common and extremely useful feature is cloning of another virtual machine as it will save you a lot of time and also resources. However, when you clone using the the 'Fast' method, you will face problem with the network card as the MAC address will be similar. This affects mostly Linux distros as Windows will boot the NIC as a new card and take in the MAC address assigned by the XenServer.
For SLES, there are a couple of things you need to do overcome this. First, take note of the correct MAC address which is displayed at the network tab of the cloned VM.
Once you have the info, move the network card configuration file to reflect the right MAC address, eg
mv ifcfg-eth-id-5e\:7f\:45\:e6\:46\:29 ifcfg-eth-id-aa\:fa\:53\:65\:40\:92
If you want to make the network card as a DHCP client, then edit the /var/lib/dhcpcd/dhcpcd-eth0.info file. At the bottom of the file, update the entry with the correct MAC address, eg
Save the file, then run the network configuration wizard using YaST and you're good to go.