General: Forums subtopic: App & System Services > Networking TN3151 Choosing the right networking API Networking Overview document — Despite the fact that this is in the archive, this is still really useful. TLS for App Developers forums post Choosing a Network Debugging Tool documentation WWDC 2019 Session 712 Advances in Networking, Part 1 — This explains the concept of constrained networking, which is Apple’s preferred solution to questions like How do I check whether I’m on Wi-Fi? TN3135 Low-level networking on watchOS TN3179 Understanding local network privacy Adapt to changing network conditions tech talk Understanding Also-Ran Connections forums post Extra-ordinary Networking forums post Foundation networking: Forums tags: Foundation, CFNetwork URL Loading System documentation — NSURLSession, or URLSession in Swift, is the recommended API for HTTP[S] on Apple platforms. Moving to Fewer, Larger Transfers forums post Testing Background Session Code forums post Network framework: Forums tag: Network Network framework documentation — Network framework is the recommended API for TCP, UDP, and QUIC on Apple platforms. Building a custom peer-to-peer protocol sample code (aka TicTacToe) Implementing netcat with Network Framework sample code (aka nwcat) Configuring a Wi-Fi accessory to join a network sample code Moving from Multipeer Connectivity to Network Framework forums post NWEndpoint History and Advice forums post Wi-Fi (general): How to modernize your captive network developer news post Wi-Fi Fundamentals forums post Filing a Wi-Fi Bug Report forums post Working with a Wi-Fi Accessory forums post — This is part of the Extra-ordinary Networking series. Wi-Fi (iOS): TN3111 iOS Wi-Fi API overview technote Wi-Fi Aware framework documentation WirelessInsights framework documentation iOS Network Signal Strength forums post Network Extension Resources Wi-Fi on macOS: Forums tag: Core WLAN Core WLAN framework documentation Secure networking: Forums tags: Security Apple Platform Security support document Preventing Insecure Network Connections documentation — This is all about App Transport Security (ATS). WWDC 2017 Session 701 Your Apps and Evolving Network Security Standards [1] — This is generally interesting, but the section starting at 17:40 is, AFAIK, the best information from Apple about how certificate revocation works on modern systems. Available trusted root certificates for Apple operating systems support article Requirements for trusted certificates in iOS 13 and macOS 10.15 support article About upcoming limits on trusted certificates support article Apple’s Certificate Transparency policy support article What’s new for enterprise in iOS 18 support article — This discusses new key usage requirements. Technote 2232 HTTPS Server Trust Evaluation Technote 2326 Creating Certificates for TLS Testing QA1948 HTTPS and Test Servers Miscellaneous: More network-related forums tags: 5G, QUIC, Bonjour On FTP forums post Using the Multicast Networking Additional Capability forums post Investigating Network Latency Problems forums post Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" [1] This video is no longer available from Apple, but the URL should help you locate other sources of this info.

Continuing with my investigations of several issues that we have been noticing in our testing of the JDK with macosx 15.x, I have now narrowed down at least 2 separate problems for which I need help. For a quick background, starting with macosx 15.x several networking related tests within the JDK have started failing in very odd and hard to debug ways in our internal lab. Reading through the macos docs and with help from others in these forums, I have come to understand that a lot of these failures are to do with the new restrictions that have been placed for "Local Network" operations. I have read through https://developer.apple.com/documentation/technotes/tn3179-understanding-local-network-privacy and I think I understand the necessary background about these restrictions. There's more than one issue in this area that I will need help with, so I'll split them out into separate topics in this forum. That above doc states: macOS 15.1 fixed a number of local network privacy bugs. If you encounter local network privacy problems on macOS 15.0, retest on macOS 15.1 or later. We did have (and continue to have) 15.0 and 15.1 macos instances within our lab which are impacted by these changes. They too show several networking related failures. However, I have decided not to look into those systems and instead focus only on 15.3.1. People might see unexpected behavior in System Settings > Privacy & Security if they have multiple versions of the same app installed (FB15568200). This feedback assistant issue and several others linked in these documentations are inaccessible (even when I login with my existing account). I think it would be good to have some facility in the feedback assistant tool/site to make such issues visible (even if read-only) to be able to watch for updates to those issues. So now coming to the issue. Several of the networking tests in the JDK do mulicasting testing (through BSD sockets API) in order to test the Java SE multicasting socket API implementations. One repeated failure we have been seeing in our labs is an exception with the message "No route to host". It shows up as: Process id: 58700 ... java.net.NoRouteToHostException: No route to host at java.base/sun.nio.ch.DatagramChannelImpl.send0(Native Method) at java.base/sun.nio.ch.DatagramChannelImpl.sendFromNativeBuffer(DatagramChannelImpl.java:914) at java.base/sun.nio.ch.DatagramChannelImpl.send(DatagramChannelImpl.java:871) at java.base/sun.nio.ch.DatagramChannelImpl.send(DatagramChannelImpl.java:798) at java.base/sun.nio.ch.DatagramChannelImpl.blockingSend(DatagramChannelImpl.java:857) at java.base/sun.nio.ch.DatagramSocketAdaptor.send(DatagramSocketAdaptor.java:178) at java.base/java.net.DatagramSocket.send(DatagramSocket.java:593) (this is just one example stacktrace from java program) That "send0" is implemented by the JDK by invoking the sendto() system call. In this case, the sendto() is returning a EHOSTUNREACH error which is what is then propagated to the application. The forum text editor doesn't allow me to post long text, so I'm going to post the rest of this investigation and logs as a reply.

Just bought a macbook pro m4, im trying to run an api on port 5000, disabled airplay receiver, checked processes, ghost ones, hidden ones, and stuck ones. I didn't find a thing using the port, but i still get port in use.

Could anyone tell me how to detect status of Local Network for iOS 18+ systems ?

Hi everyone, I developed an Android version of a VPN app built with Flutter using OpenVPN, and it works perfectly on Android. However, when porting it to iOS, I’ve encountered an issue: the app connects successfully but then automatically disconnects when tested via TestFlight. We’ve already added all the necessary network extensions. Despite this, we decided to submit the app to the App Store. It’s been five days now, and the app is still 'Waiting for Review.' Could anyone share their experience deploying and working on an iOS version of a VPN app? I’d really appreciate your insights!

My app sent a network request to the backend. The backend returns a 200, but the front end received a -1001 or -1005 NSURLError. Any clue why this could be happening?

Could anyone teach me how to ask iOS 18 to have a prompt during set-up process of a new APP if user accidentally turns off Local Network ?

Is it possible using the network framework to retrieve the list of certificates presented by the host alone, and not the reconstructed chain assembled by the system? For example, in OpenSSL one can call SSL_get_peer_cert_chain which will return exactly this - a list of the certificates presented by the server. This is useful for when you may want to manually reconstruct the chain, or if the server is misconfigured (for example, is missing an intermediate cert). Is something like this possible with the network framework? If I connect to a host that I know only returns 1 certificate, the trust ref already has the reconstructed chain by the time my code is called: sec_protocol_options_set_verify_block(tlsOptions.securityProtocolOptions, { metadata, trustRef, verifyComplete in let trust = sec_trust_copy_ref(trustRef).takeRetainedValue() let numberOfCertificates = SecTrustGetCertificateCount(trust) // Returns 3 even though the server only sent 1

When I use NSURLSessionTaskTransactionMetrics property domainLookupStartDate and domainLookupEndDate to calculate the duration of DNS, sometimes I get 4294893875545978 or -4294893875545978 return method like this [NSNumber numberWithLongLong:[taskMetrics.domainLookupEndDate timeIntervalSinceDate:taskMetrics.domainLookupStartDate?]*1000000000] The hexadecimal value of 4294893875545978 is 0xF3F3F3F3F3F3A. Is 4294893875545978 a special value？

Hello, Title states it basically. I have a java program (launched via shell script) running as a service using launchd which is running as a user (not root) and it does not request Local Network permissions ever. I feel like i'm missing something here. I combed through all of the Local Network FAQs and don't really see this use case addressed. I do see that there is an open ticket for an API to trigger the request, but no update on that and the ticket is not visible publicly. Is there is a way to accomplish this for java or other programs running via launchd with a user other than root? something like an entitlement or an API to seed the permission of Local Network when installing the service via launchctl etc?

We have developed a DNS filter based on NEDNSProxyProvider. It works great for a minute, then it stops responding. Our logs indicate that during the outage our extension gets DNS requests and formulates DNS responses that it hands back to the OS, but from outside of our code it is as though our extension is not responding.

On iOS 18.3, I noted that partition "HTTPCookiePropertyKey: StoragePartition" is not observed to be set for cookies returned from the wkwebview cookie store. Now on 18.4 beta 4 we are now seeing those same cookies are populated with a partition property. Is there documentation for this change? Is it intended to be suddenly populated in 18.4? Now that partition property is set, HTTPCookieStorage.shared.cookies(for: serverUri) doesn't seem to return the expected cookies correctly. For context, we are using the cookies extracted from wkwebview, setting them in HTTPCookieStorage.shared and using URLSession to make network calls outside the webivew. Works fine once I forcefully set partition on the cookie to nil. More details on what the cookie looks like here: https://feedbackassistant.apple.com/feedback/16906526 Hopefully this is on your radar?

Apology for repost. I needed to fix the tags for original thread. https://developer.apple.com/forums/thread/777159 On iOS 18.3, I noted that partition "HTTPCookiePropertyKey: StoragePartition" is not observed to be set for cookies returned from the wkwebview cookie store. Now on 18.4 beta 4 we are now seeing those same cookies are populated with a partition property. Is there documentation for this change? Is it intended to be suddenly populated in 18.4? Now that partition property is set, HTTPCookieStorage.shared.cookies(for: serverUri) doesn't seem to return the expected cookies correctly. For context, we are using the cookies extracted from wkwebview, setting them in HTTPCookieStorage.shared and using URLSession to make network calls outside the webivew. Works fine once I forcefully set partition on the cookie to nil. More details on what the cookie looks like here: https://feedbackassistant.apple.com/feedback/16906526 Hopefully this is on your radar?

When I make a local network HTTP request, an error occurs. I'm sure I've granted wireless data permissions and local network permissions, and I'm connected to the correct Wi-Fi. This problem is intermittent, but once it happens, it will keep happening, and the only way to fix it is to restart the phone. Here is the error log: sessionTaskFailed(error: Error Domain=NSURLErrorDomain Code=-1009 "似乎已断开与互联网的连接。" UserInfo={_kCFStreamErrorCodeKey=50, NSUnderlyingError=0x30398a5b0 {Error Domain=kCFErrorDomainCFNetwork Code=-1009 "(null)" UserInfo={_NSURLErrorNWPathKey=unsatisfied (Local network prohibited), interface: en0[802.11], uses wifi, _kCFStreamErrorCodeKey=50, _kCFStreamErrorDomainKey=1}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask .<63>, _NSURLErrorRelatedURLSessionTaskErrorKey=( "LocalDataTask .<63>" ), NSLocalizedDescription=似乎已断开与互联网的连接。, NSErrorFailingURLStringKey=http://192.168.2.1:80/v1/parameters, NSErrorFailingURLKey=http://192.168.2.1:80/v1/parameters, _kCFStreamErrorDomainKey=1})

Hi there, can some one help how to debug this crashes? where I can start to find root causes of this crashes. I've got lot of these NSInvalidArgumentException crashes in myapp last version I have no idea how to reproduce these issues since it doesn't point to any specific code on myapp, so I don't know how to start Fatal Exception: NSInvalidArgumentException -[NWConcrete_nw_protocol_options copyWithZone:]: unrecognized selector sent to instance 0x283391d60 Fatal Exception: NSInvalidArgumentException -[NSConcreteHashTable lengthOfBytesUsingEncoding:]: unrecognized selector sent to instance 0x281d4cbe0 Fatal Exception: NSInvalidArgumentException -[_NSXPCConnectionExportedObjectTable lengthOfBytesUsingEncoding:]: unrecognized selector sent to instance 0x2829d11d0 Fatal Exception: NSInvalidArgumentException -[OS_dispatch_group lengthOfBytesUsingEncoding:]: unrecognized selector sent to instance 0x281a11900 Fatal Exception: NSInvalidArgumentException -[__NSCFData getBytes:maxLength:usedLength:encoding:options:range:remainingRange:]: unrecognized selector sent to instance 0x28210e440 Fatal Exception: NSInvalidArgumentException -[_NSCoreTypesetterLayoutCache copyWithZone:]: unrecognized selector sent to instance 0x283bbc730 Thanks com.kitabisa.ios_issue_dd3c71c96cddb5bb99874640746439d6_crash_session_de9bb41c2b7e43fa9ccfc42e0f649aa3_DNE_0_v2_stacktrace.txt

The newly introduced enum value NEProviderStopReasonInternalError (macOS 15.1) is not documented (assuming being documented means having at least a sentence describing the enum value). [Q] What kind of situation is the NEProviderStopReasonInternalError enum value supposed to describe? An internal error that requires to try to restart the provider? A fatal error that requires to reinstall macOS? A fatal error that requires to purchase a new Mac? Something less serious but with a human friendly description in the headers (I'm using Xcode 16.2) and online documentation.

I'm simply trying to use a proxy to route a http request in Swift. I've tried using a URLSession Delegate but that results in the same issue with the iOS menu. proxy format: host:port:username:password When I run the code below I am prompted with a menu to add credentials for the proxy. I closed this menu inside my app and tried the function below again and it worked without giving me the menu a second time. However even though the function works without throwing any errors, it does NOT use the proxies to route the request. I've spent days on this and the only solution I found was using a NWConnection but this is super low level and now I need a shared session to manage cookies. If you want to see the NWConnection solution I made its here func averageProxyGroupSpeed(proxies: [String], completion: @escaping (Int, String) -> Void) { let numProxies = proxies.count if numProxies == 0 { completion(0, "No proxies") return } var totalTime: Int64 = 0 var successCount = 0 let group = DispatchGroup() let queue = DispatchQueue(label: "proxyQueue", attributes: .concurrent) let lock = NSLock() let shuffledProxies = proxies.shuffled() let selectedProxies = Array(shuffledProxies.prefix(25)) for proxy in selectedProxies { group.enter() queue.async { let proxyDetails = proxy.split(separator: ":").map(String.init) guard proxyDetails.count == 4, let port = Int(proxyDetails[1]), let url = URL(string: "http://httpbin.org/get") else { completion(0, "Invalid proxy format") group.leave() return } var request = URLRequest(url: url) request.timeoutInterval = 15 let configuration = URLSessionConfiguration.default configuration.connectionProxyDictionary = [ AnyHashable("HTTPEnable"): true, AnyHashable("HTTPProxy"): proxyDetails[0], AnyHashable("HTTPPort"): port, AnyHashable("HTTPSEnable"): false, AnyHashable("HTTPUser"): proxyDetails[2], AnyHashable("HTTPPassword"): proxyDetails[3] ] let session = URLSession(configuration: configuration) let start = Date() let task = session.dataTask(with: request) { _, _, error in defer { group.leave() } if let error = error { print("Error: \(error.localizedDescription)") } else { let duration = Date().timeIntervalSince(start) * 1000 lock.lock() totalTime += Int64(duration) successCount += 1 lock.unlock() } } task.resume() } } group.notify(queue: DispatchQueue.main) { if successCount == 0 { completion(0, "Proxies Failed") } else { let averageTime = Int(Double(totalTime) / Double(successCount)) completion(averageTime, "") } } } Delegate example class ProxySessionDelegate: NSObject, URLSessionDelegate { let username: String let password: String init(username: String, password: String) { self.username = username self.password = password } func urlSession(_ session: URLSession, task: URLSessionTask, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) { if challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodHTTPBasic { let credential = URLCredential(user: self.username, password: self.password, persistence: .forSession) completionHandler(.useCredential, credential) } else { completionHandler(.performDefaultHandling, nil) } } }

I am trying to convert a simple URLSession request in Swift to using NWConnection. This is because I want to make the request using a Proxy that requires Authentication. I posted this SO Question about using a proxy with URLSession. Unfortunately no one answered it but I found a fix by using NWConnection instead. Working Request func updateOrderStatus(completion: @escaping (Bool) -> Void) { let orderLink = "https://shop.ccs.com/51913883831/orders/f3ef2745f2b06c6b410e2aa8a6135847" guard let url = URL(string: orderLink) else { completion(true) return } let cookieStorage = HTTPCookieStorage.shared let config = URLSessionConfiguration.default config.httpCookieStorage = cookieStorage config.httpCookieAcceptPolicy = .always let session = URLSession(configuration: config) var request = URLRequest(url: url) request.httpMethod = "GET" request.setValue("text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8", forHTTPHeaderField: "Accept") request.setValue("none", forHTTPHeaderField: "Sec-Fetch-Site") request.setValue("navigate", forHTTPHeaderField: "Sec-Fetch-Mode") request.setValue("Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.0.1 Safari/605.1.15", forHTTPHeaderField: "User-Agent") request.setValue("en-US,en;q=0.9", forHTTPHeaderField: "Accept-Language") request.setValue("gzip, deflate, br", forHTTPHeaderField: "Accept-Encoding") request.setValue("document", forHTTPHeaderField: "Sec-Fetch-Dest") request.setValue("u=0, i", forHTTPHeaderField: "Priority") // make the request } Attempted Conversion func updateOrderStatusProxy(completion: @escaping (Bool) -> Void) { let orderLink = "https://shop.ccs.com/51913883831/orders/f3ef2745f2b06c6b410e2aa8a6135847" guard let url = URL(string: orderLink) else { completion(true) return } let proxy = "resi.wealthproxies.com:8000:akzaidan:x0if46jo-country-US-session-7cz6bpzy-duration-60" let proxyDetails = proxy.split(separator: ":").map(String.init) guard proxyDetails.count == 4, let port = UInt16(proxyDetails[1]) else { print("Invalid proxy format") completion(false) return } let proxyEndpoint = NWEndpoint.hostPort(host: .init(proxyDetails[0]), port: NWEndpoint.Port(integerLiteral: port)) let proxyConfig = ProxyConfiguration(httpCONNECTProxy: proxyEndpoint, tlsOptions: nil) proxyConfig.applyCredential(username: proxyDetails[2], password: proxyDetails[3]) let parameters = NWParameters.tcp let privacyContext = NWParameters.PrivacyContext(description: "ProxyConfig") privacyContext.proxyConfigurations = [proxyConfig] parameters.setPrivacyContext(privacyContext) let host = url.host ?? "" let path = url.path.isEmpty ? "/" : url.path let query = url.query ?? "" let fullPath = query.isEmpty ? path : "\(path)?\(query)" let connection = NWConnection( to: .hostPort( host: .init(host), port: .init(integerLiteral: UInt16(url.port ?? 80)) ), using: parameters ) connection.stateUpdateHandler = { state in switch state { case .ready: print("Connected to proxy: \(proxyDetails[0])") let httpRequest = """ GET \(fullPath) HTTP/1.1\r Host: \(host)\r Connection: close\r Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.0.1 Safari/605.1.15\r Accept-Language: en-US,en;q=0.9\r Accept-Encoding: gzip, deflate, br\r Sec-Fetch-Dest: document\r Sec-Fetch-Mode: navigate\r Sec-Fetch-Site: none\r Priority: u=0, i\r \r """ connection.send(content: httpRequest.data(using: .utf8), completion: .contentProcessed({ error in if let error = error { print("Failed to send request: \(error)") completion(false) return } // Read data until the connection is complete self.readAllData(connection: connection) { finalData, readError in if let readError = readError { print("Failed to receive response: \(readError)") completion(false) return } guard let data = finalData else { print("No data received or unable to read data.") completion(false) return } if let body = String(data: data, encoding: .utf8) { print("Received \(data.count) bytes") print("\n\nBody is \(body)") completion(true) } else { print("Unable to decode response body.") completion(false) } } })) case .failed(let error): print("Connection failed for proxy \(proxyDetails[0]): \(error)") completion(false) case .cancelled: print("Connection cancelled for proxy \(proxyDetails[0])") completion(false) case .waiting(let error): print("Connection waiting for proxy \(proxyDetails[0]): \(error)") completion(false) default: break } } connection.start(queue: .global()) } private func readAllData(connection: NWConnection, accumulatedData: Data = Data(), completion: @escaping (Data?, Error?) -> Void) { connection.receive(minimumIncompleteLength: 1, maximumLength: 65536) { data, context, isComplete, error in if let error = error { completion(nil, error) return } // Append newly received data to what's been accumulated so far let newAccumulatedData = accumulatedData + (data ?? Data()) if isComplete { // If isComplete is true, the server closed the connection or ended the stream completion(newAccumulatedData, nil) } else { // Still more data to read, so keep calling receive self.readAllData(connection: connection, accumulatedData: newAccumulatedData, completion: completion) } } }

Problem Description When using iCloud Private Relay (Limit IP address tracking) on macOS Sonoma, I'm experiencing a DNS resolving issue when simultaneously connected via OpenVPN. The system activates iCloud Private Relay instead of using the DNS servers provided by the VPN connection, resulting in incorrect IP address resolution. Specific issues: When connected to my company VPN, the system ignores DNS servers set by the VPN connection When attempting to ping internal servers in the corporate network, I receive public IP addresses instead of internal corporate IP addresses These public IP addresses are not accessible from outside as some services are disabled for external access Tools like nslookup and dig correctly resolve internal addresses, but ping and regular applications use incorrect (public) IP addresses Access to local servers in the corporate network/subnet is problematic Expected Behavior I need the system to: Use DNS servers provided by the VPN connection for accessing internal corporate resources when connected via VPN Simultaneously maintain iCloud Private Relay protection for regular internet browsing while connected to VPN Technical Details Based on available information, the problem is likely caused by "iCloud Private Relay" inserting an additional DNS resolver that isn't visible through the scutil tool. Regular applications use macOS internal API for DNS resolving, while tools like dig and nslookup work differently. According to Apple documentation, it should be possible to use custom DNS settings with iCloud Private Relay, but it doesn't seem to work properly with OpenVPN. Temporary Solutions I've Tried Some sources suggest: Disabling iCloud Private Relay (I don't want to lose privacy protection) Creating an /etc/resolver directory with configuration for specific domains Manually adding static routes for specific IP addresses None of these solutions provide the ideal combination of VPN DNS functionality and privacy protection. Request for Solution Please implement a solution that allows: Prioritizing DNS servers provided by VPN connection for internal domains Maintaining iCloud Private Relay protection for other communications Ensuring consistent behavior of all applications during DNS resolving Thank you for your help.

It doesn’t seem like there’s any high level, first-party documentation on how to use what is the recommended API for executing networking logic that you otherwise wouldn’t use URLSession for; which is a lot of things. There’s a sample app, and docs on how to choose the right network API in general, but apparently no high level API docs for Network.framework itself. Am I missing something? How do people learn to use this? Know which classes to use? Know the various ways it can be configured?

Hello, I'm having some problems starting my DNS proxy network extension. Even after I call NEDNSProxyManager.saveToPreference() successfully I don't see any logs from my dns proxy. This is the code from the user space app: import SwiftUI import NetworkExtension func configureDNSProxy() { let dnsProxyManager = NEDNSProxyManager.shared() dnsProxyManager.loadFromPreferences { error in if let error = error { print("Error loading DNS proxy preferences: \(error)") return } dnsProxyManager.localizedDescription = "my DNS proxy" let proto = NEDNSProxyProviderProtocol() proto.providerBundleIdentifier = "com.myteam.dns-proxy-tests.ne" dnsProxyManager.providerProtocol = proto // Enable the DNS proxy. dnsProxyManager.isEnabled = true dnsProxyManager.saveToPreferences { error in if let error = error { print("Error saving DNS proxy preferences: \(error)") } else { NSLog("DNS Proxy enabled successfully") } } } } @main struct dns_proxy_testsApp: App { var body: some Scene { WindowGroup { ContentView() } } init() { configureDNSProxy() } } This is the code for my network extension(DNSProxyProvider.swift): import NetworkExtension class DNSProxyProvider: NEDNSProxyProvider { override func startProxy(options:[String: Any]? = nil, completionHandler: @escaping (Error?) -> Void) { NSLog("dns proxy ne started") completionHandler(nil) } override func stopProxy(with reason: NEProviderStopReason, completionHandler: @escaping () -> Void) { NSLog("dns proxy ne stopped") completionHandler() } override func sleep(completionHandler: @escaping () -> Void) { NSLog("dns proxy ne sleep") completionHandler() } override func wake() { NSLog("dns proxy ne wake") } override func handleNewFlow(_ flow: NEAppProxyFlow) -> Bool { NSLog("dns proxy ne flow") return true } } The bundle identifier for my network extension is: com.myteam.dns-proxy-tests.ne and both the user space app and the network extension have the DNS Proxy capability. Both have the same app group capability with the same group name group.com.myteam.dns-proxy-test. The info.plist from the network extension look like this(I didn't really modify it from the default template created by xcode) <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>NetworkExtension</key> <dict> <key>NEMachServiceName</key> <string>$(TeamIdentifierPrefix)com.example.app-group.MySystemExtension</string> <key>NEProviderClasses</key> <dict> <key>com.apple.networkextension.dns-proxy</key> <string>$(PRODUCT_MODULE_NAME).DNSProxyProvider</string> </dict> </dict> </dict> </plist> In the logs I do see DNS Proxy enabled successfully and also I see: NESMDNSProxySession[Primary Tunnel:my DNS proxy:<...>:(null)] starting with configuration: { name = my DNS proxy identifier = <..> applicationName = dns-proxy-tests application = com.myteam.dns-proxy-tests grade = 1 dnsProxy = { enabled = YES protocol = { type = dnsProxy identifier = <...> identityDataImported = NO disconnectOnSleep = NO disconnectOnIdle = NO disconnectOnIdleTimeout = 0 disconnectOnWake = NO disconnectOnWakeTimeout = 0 disconnectOnUserSwitch = NO disconnectOnLogout = NO includeAllNetworks = NO excludeLocalNetworks = NO excludeCellularServices = YES excludeAPNs = YES excludeDeviceCommunication = YES enforceRoutes = NO pluginType = com.myteam.dns-proxy-tests providerBundleIdentifier = com.myteam.dns-proxy-tests.ne designatedRequirement = identifier "com.myteam.dns-proxy-tests.ne" <...> /* exists */ } } } But then I see: Checking for com.myteam.dns-proxy-tests.ne - com.apple.networkextension.dns-proxy But then finally Found 0 registrations for com.myteam.dns-proxy-tests.ne (com.apple.networkextension.dns-proxy) So I think that last log probably indicates the problem. I'm a bit lost at what I'm doing wrong so I'd be super thankful for any pointer!