Host Information

An NSHost object holds network name and address information for a host. You use this class to get the current host’s name and address and to look up other hosts by name or by address. The class uses available network administration services (such as NetInfo or the Domain Name Service) to discover all requested names and addresses for the host. It does not attempt to contact the host itself, however. This avoids untimely delays due to a host being unavailable, but it may result in incomplete information about the host.

An NSHost object contains all of the network addresses and names discovered for a given host by the network administration services. Each NSHost object typically contains one unique address, but it may have more than one name. If the host has more than one name, the additional names are usually variations on the same name—typically the basic host name plus the fully qualified domain name. For example, with a host name “sales” in the domain “”, an NSHost object can hold both the names “sales” and “”.

The NSHost class maintains a cache of previously created instances so that requests for an existing NSHost object return that object instead of creating a new one. Use the setHostCacheEnabled: method to turn the cache off, forcing lookup of hosts as they’re requested. You can also use the flushHostCache method to clear the cache of its entries so that subsequent requests look up the host information and create new instances.

THe NSHost class is available in Objective-C only. Java developers can use the class instead.