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# NSPortNameServer

An object-oriented interface to the port registration service used by the distributed objects system.

```
@interface NSPortNameServer : NSObject
```

## Overview

[`NSConnection`](/documentation/Foundation/NSConnection) objects use this interface to contact each other and to distribute objects over the network; you should rarely need to interact directly with an [`NSPortNameServer`](/documentation/Foundation/NSPortNameServer).

You get an [`NSPortNameServer`](/documentation/Foundation/NSPortNameServer) object by using the [`systemDefaultPortNameServer`](/documentation/Foundation/NSPortNameServer/systemDefaultPortNameServer) class method—never allocate and initialize an instance directly. With the default server object you can register an [`Port`](/documentation/Foundation/Port) object under a given name, making it available on the network, and also unregister it so that it can’t be looked up (although other applications that have already looked up the [`Port`](/documentation/Foundation/Port) object  can still use it until it becomes invalid). See the [`Port`](/documentation/Foundation/Port) class specification for more information.

## Topics

### Getting the Server Object

[`systemDefaultPortNameServer`](/documentation/Foundation/NSPortNameServer/systemDefaultPortNameServer)

Returns the single instance of `NSPortNameServer` for the application.

### Looking up Ports

[`portForName:`](/documentation/Foundation/NSPortNameServer/portForName:)

Looks up and returns the port registered under the specified name on the local host.

[`portForName:host:`](/documentation/Foundation/NSPortNameServer/portForName:host:)

Looks up and returns the port registered under the specified name on a specified host.

### Registering Ports

[`registerPort:name:`](/documentation/Foundation/NSPortNameServer/registerPort:name:)

Makes a given port available on the network under a specified name.

[`removePortForName:`](/documentation/Foundation/NSPortNameServer/removePortForName:)

Unregisters the port for a given name on the local host.


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