---
title: kCFDNSServiceFailureKey
framework: cfnetwork
role: symbol
role_heading: Global Variable
path: cfnetwork/kcfdnsservicefailurekey
---

# kCFDNSServiceFailureKey

## Declaration

```swift
let kCFDNSServiceFailureKey: CFString
```

## Discussion

Discussion If an error of type kCFNetServicesErrorDNSServiceFailure is returned, querying this key returns the last error returned by the DNS resolver libraries in response to the previous operation. To interpret the results, look up the error codes in /usr/include/dns_sd.h or DNS Service Discovery C.

## See Also

### Constants

- [kCFURLErrorFailingURLErrorKey](cfnetwork/kcfurlerrorfailingurlerrorkey.md)
- [kCFURLErrorFailingURLStringErrorKey](cfnetwork/kcfurlerrorfailingurlstringerrorkey.md)
- [kCFGetAddrInfoFailureKey](cfnetwork/kcfgetaddrinfofailurekey.md)
- [kCFSOCKSStatusCodeKey](cfnetwork/kcfsocksstatuscodekey.md)
- [kCFSOCKSVersionKey](cfnetwork/kcfsocksversionkey.md)
- [kCFSOCKSNegotiationMethodKey](cfnetwork/kcfsocksnegotiationmethodkey.md)
- [kCFFTPStatusCodeKey](cfnetwork/kcfftpstatuscodekey.md)