Ok, i figured that out, in fact it was pretty easy: 
Hi there.  I currently have an environment without DNS server.  In the training material it says: In a closed environment with no external network connections in which the clients connect only to an Isilon cluster, SmartConnect can act as the DNS server. In this instance, the clients use the SmartConnect IP address as their DNS server address.  Do i have to set up the local "hosts" file on the servers for that or do i simply set the SmartConnect service IP as DNS server? And what about the SmartConnect zone name?  Anyone can help me on that?
Isilon SmartConnect without DNS Server