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# NEFilterErrorDomain

The domain for errors resulting from calls to the filter manager.

```
let NEFilterErrorDomain: String
```

## Discussion

Match this constant to the <doc://com.apple.documentation/documentation/Foundation/NSError/domain> of an <doc://com.apple.documentation/documentation/Foundation/NSError> encountered when calling methods on [`NEFilterManager`](/documentation/NetworkExtension/NEFilterManager). The [`NEFilterManagerError`](/documentation/NetworkExtension/NEFilterManagerError) enumeration defines possible <doc://com.apple.documentation/documentation/Foundation/NSError/code> values for these errors.

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