Each computer on the network may have a number of DNS names. For example, the web server www.indigo-insurance.com may also be known as boston.indigo-insurance.com.
In a network containing a firewall, you can ensure that some names are usable outside the firewall -- across the Internet, for example -- and others are usable inside the firewall. For example, users outside the firewall might be able to use www.indigo-insurance.com, but not boston.indigo-insurance.com. Users inside the firewall might be able to use either name.
The Tarantella three-tier architecture can straddle firewalls, allowing access from client devices across the Internet.
These two DNS names may be associated with the same network card (NIC) on the Tarantella host, or they may each use a different network card.