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Explore the networking protocols and technologies used by the device to connect to Wi-Fi networks, Bluetooth devices, and cellular data services.

Networking Documentation

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Disable URLSession auto retry policy
We are developing an iOS application that is interacting with HTTP APIs that requires us to put a unique UUID (a nonce) as an header on every request (obviously there's more than that, but that's irrilevant to the question here). If the same nonce is sent on two subsequent requests the server returns a 412 error. We should avoid generating this kind of errors as, if repeated, they may be flagged as a malicious activity by the HTTP APIs. We are using URLSession.shared.dataTaskPublisher(for: request) to call the HTTP APIs with request being generated with the unique nonce as an header. On our field tests we are seeing a few cases of the same HTTP request (same nonce) being repeated a few seconds on after the other. Our code has some retry logic only on 401 errors, but that involves a token refresh, and this is not what we are seeing from logs. We were able to replicate this behaviour on our own device using Network Link Conditioner with very bad performance, with XCode's Network inspector attached we can be certain that two HTTP requests with identical headers are actually made automatically, the first request has an "End Reason" of "Retry", the second is "Success" with Status 412. Our questions are: can we disable this behaviour? can we provide a new request for the retry (so that we can update headers)? Thanks, Francesco
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306
Aug ’25
Level Networking on watchOS for Duplex audio streaming
I did watch WWDC 2019 Session 716 and understand that an active audio session is key to unlocking low‑level networking on watchOS. I’m configuring my audio session and engine as follows: private func configureAudioSession(completion: @escaping (Bool) -> Void) { let audioSession = AVAudioSession.sharedInstance() do { try audioSession.setCategory(.playAndRecord, mode: .voiceChat, options: []) try audioSession.setActive(true, options: .notifyOthersOnDeactivation) // Retrieve sample rate and configure the audio format. let sampleRate = audioSession.sampleRate print("Active hardware sample rate: \(sampleRate)") audioFormat = AVAudioFormat(standardFormatWithSampleRate: sampleRate, channels: 1) // Configure the audio engine. audioInputNode = audioEngine.inputNode audioEngine.attach(audioPlayerNode) audioEngine.connect(audioPlayerNode, to: audioEngine.mainMixerNode, format: audioFormat) try audioEngine.start() completion(true) } catch { print("Error configuring audio session: \(error.localizedDescription)") completion(false) } } private func setupUDPConnection() { let parameters = NWParameters.udp parameters.includePeerToPeer = true connection = NWConnection(host: "***.***.xxxxx.***", port: 0000, using: parameters) setupNWConnectionHandlers() } private func setupTCPConnection() { let parameters = NWParameters.tcp connection = NWConnection(host: "***.***.xxxxx.***", port: 0000, using: parameters) setupNWConnectionHandlers() } private func setupWebSocketConnection() { guard let url = URL(string: "ws://***.***.xxxxx.***:0000") else { print("Invalid WebSocket URL") return } let session = URLSession(configuration: .default) webSocketTask = session.webSocketTask(with: url) webSocketTask?.resume() print("WebSocket connection initiated") sendAudioToServer() receiveDataFromServer() sendWebSocketPing(after: 0.6) } private func setupNWConnectionHandlers() { connection?.stateUpdateHandler = { [weak self] state in DispatchQueue.main.async { switch state { case .ready: print("Connected (NWConnection)") self?.isConnected = true self?.failToConnect = false self?.receiveDataFromServer() self?.sendAudioToServer() case .waiting(let error), .failed(let error): print("Connection error: \(error.localizedDescription)") DispatchQueue.main.asyncAfter(deadline: .now() + 2) { self?.setupNetwork() } case .cancelled: print("NWConnection cancelled") self?.isConnected = false default: break } } } connection?.start(queue: .main) } I am reaching out to seek further assistance regarding the challenges I've been experiencing with establishing a UDP, TCP & web socket connection on watchOS using NWConnection for duplex audio streaming. Despite implementing the recommendations provided earlier, I am still encountering difficulties. Or duplex audio streaming not possible on apple watch?
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168
Apr ’25
Archived app failing to get root certificates for SSL websocket connection
I've had a Unreal Engine project that uses libwebsocket to make a websocket connection with SSL to a server. Recently I made a build using Unreal Engine 5.4.4 on MacOS Sequoia 15.5 and XCode 16.4 and for some reason the websocket connection now fails because it can't get the local issuer certificate. It fails to access the root certificate store on my device (Even though, running the project in the Unreal Editor works fine, it's only when making a packaged build with XCode that it breaks) I am not sure why this is suddenly happening now. If I run it in the Unreal editor on my macOS it works fine and connects. But when I make a packaged build which uses XCode to build, it can't get the local issuer certificate. I tried different code signing options, such as sign to run locally or just using sign automatically with a valid team, but I'm not sure if code signing is the cause of this issue or not. This app is only for development and not meant to be published, so that's why I had been using sign to run locally, and that used to work fine but not anymore. Any guidance would be appreciated, also any information on what may have changed that now causes this certificate issue to happen. I know Apple made changes and has made notarizing MacOS apps mandatory, but I'm not sure if that also means a non-notarized app will now no longer have access to the root certificate store of a device, in my research I haven't found anything about that specifically, but I'm wondering if any Apple engineers might know something about this that hasn't been put out publicly.
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128
Nov ’25
NSURLErrorDomain Code=-1003 ... again!
This happens when trying to connect to my development web server. The app works fine when connecting to my production server. The production server has a certificate purchased from a CA. My development web server has a locally generated certificate (from mkcert). I have dragged and dropped the rootCA.pem onto the Simulator, although it doesn't indicate it has been loaded the certificate does appear in the Settings app and is checked to be trusted. I have enabled "App Sandbox" and "Outgoing connections (Client)". I have tested the URL from my local browser which is working fine. What am I missing?
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704
Jul ’25
Content Filter Providers in unsupervised and unmanaged iOS devices
I'm looking at implementing an iOS app that has includes a Content Filter Provider to block access to certain domains when accessed on the device. This uses NEFilterManager, NEFilterDataProvider and NEFilterControlProvider to handle configuration and manage the network flows and block as necessary. My question is can you deploy this in an iOS 18+ app on the App Store to devices which are unmanaged, unsupervised and don't use Screen Time APIs? Although not 100% clear, this technote seems to say it is not possible: https://developer.apple.com/documentation/Technotes/tn3134-network-extension-provider-deployment Testing this on a Developer device and build works successfully without any MDM profiles installed. A similar approach using the same APIs also works on macOS once user permissions have been given. If it can't work on unsupervised, unmanaged iOS devices, is possible for the user to first manually install a MDM profile which includes the required 'Content Filter' details and then have it work? If not, how would you filter iOS network traffic on an unmanaged, unsupervised device? Is it necessary to use a VPN or DNS approach instead (which may be a lot less privacy compliant)?
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438
Feb ’25
Performance degradation of HTTP/3 requests in iOS app under specific network conditions
Hello Apple Support Team, We are experiencing a performance issue with HTTP/3 in our iOS application during testing. Problem Description: Network requests using HTTP/3 are significantly slower than expected. This issue occurs on both Wi-Fi and 4G networks, with both IPv4 and IPv6. The same setup worked correctly in an earlier experiment. Key Observations: The slowdown disappears when the device uses: · A personal hotspot. · Network Link Conditioner (with no limitations applied). · Internet sharing from a MacBook via USB (where traffic was also inspected with Wireshark without issues). The problem is specific to HTTP/3 and does not occur with HTTP/2. The issue is reproducible on iOS 15, 18.7, and the latest iOS 26 beta. HTTP/3 is confirmed to be active (via assumeHttp3Capable and Alt-Svc header). Crucially, the same backend endpoint works with normal performance on Android devices and using curl with HTTP/3 support from the same network. I've checked the CFNetwork logs in the Console but haven't found any suspicious errors or obvious clues that explain the slowdown. We are using a standard URLSession with basic configuration. Attempted to collect qlog diagnostics by setting the QUIC_LOG_DIRECTORY=~/ tmp environment variable, but the logs were not generated. Question: What could cause HTTP/3 performance to improve only when the device is connected through a hotspot, unrestricted Network Link Conditioner, or USB-tethered connection? The fact that Android and curl work correctly points to an issue specific to the iOS network stack. Are there known conditions or policies (e.g., related to network interface handling, QoS, or specific packet processing) that could lead to this behavior? Additionally, why might the qlog environment variable fail to produce logs, and are there other ways to obtain detailed HTTP/3 diagnostic information from iOS? Any guidance on further diagnostic steps or specific system logs to examine would be greatly appreciated. Thank you for your assistance.
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317
Nov ’25
How many instances of the same NEFilterDataProvider can there be in a running NE?
[Q] How many instances of the same NEFilterDataProvider subclass can there be in a single running Network Extension at any given time? I would expect that there can be only 1 instance but I'm looking at a memgraph where 2 instances are listed. As it's the Network Extension framework that is responsible for creating, starting and stopping these instances, this is rather strange.
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142
Jul ’25
WifiAware Endpoint usage and impact on infrastructure Wifi
Are the Wifi-Aware's WAEndpoint's discovered ephemeral? I'm trying to understand what's the best way to reconnect a disconnected WifiAware connection - Can I just cache the endpoint and start a new connection with the same endpoint or do I need to browse again and get a new WAEndpoint? My use case requires both WifiAware connection to another device and the devices also need to be connected to infrastructure wifi most of the time. I'm concerned about the WifiAware's connection having any impact on infrastructure wifi. What is the impact on the infrastructure wifi here in comparison to using the Apple peer to peer wifi(That Multipeer framework or Network framework use)?
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202
Oct ’25
My app suddenly getting "A server with the specified hostname could not be found"
I've had no problem running my app in a simulator or on a device, but today my app is failing on a URLRequest to my local machine (in a sim). From the same simulator I can go to Safari and manually enter the URL that the app is using (and that appears in the error message), and it works fine. I think there was a recent Xcode update; did something change in this regard?
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212
May ’25
NEPacketTunnelProvider Start Issue on macOS 14.5
We're encountering an issue with our Network Extension (utilizing NEPacketTunnelProvider and NETransparentProxy) on macOS 14.5 (23F79). On some systems, the VPN fails to automatically start after a reboot despite calling startVPNTunnel(). There are no error messages. Our code attempts to start the tunnel: ....... do { try manager.connection.startVPNTunnel() Logger.default("Started tunnel successfully") } catch { Logger.error("Failed to launch tunnel") } ...... System log analysis reveals the tunnel stopping due to userLogout (NEProviderStopReason(rawValue: 12)) during reboot. However, the Transparent Proxy stops due to userInitiated (NEProviderStopReason(rawValue: 1)) for the same reboot. We need to understand: Why the VPNTunnel isn't starting automatically. Why the userLogout reason is triggered during reboot. Additional Context: We have manually started the VPN from System Settings before reboot.
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762
Oct ’25
How can I programmatically access the NETunnelProviderManager of a Per-App VPN?
I have an iOS app which contains a Network Extension that subclasses the NEPacketTunnelProvider, acting as a packet-tunnel VPN. After deploying the app on the device as a regular app, it runs the following code fragment: NETunnelProviderManager.loadAllFromPreferences { managers, _ in self.manager = managers?.first ?? NETunnelProviderManager() self.manager.protocolConfiguration = getConfiguration() self.manager.saveToPreferences { error in // Handle errors or show a "Connect" button in the UI } } This asks the user to install the extension as a "Device VPN". I can then use try? self.manager?.connection.startVPNTunnel() to start the VPN (and later stop it when needed). So far, this works fine. Now, I want to deploy the app with an MDM and set it up as the "custom VPN" of a "Per-App VPN". I have tested the setup using a real MDM, AND using the "development" setup described in NETunnelProviderManager. In both cases, the "Per-App VPN" shows up as a VPN in the "Settings" app. However, in both cases I am unable to retrieve, configure or use the "Per-App VPN". The code fragment posted above returns no NETunnelProviderManager at all. When instantiating one on my own and triggering self.manager.saveToPreferences(), it queries the user to install a "Device VPN". While I can control and use the latter, this is clearly not what I want after having gone through the pain of installing the "Per-App VPN". How can I retrieve the NETunnelProviderManager of the "Per-App VPN"? And then use it to configure and control the VPN connection? (Ideally, I would like to use the same app and the same Network Extension for both use cases, leaving the choice of which VPN type to use to the user or the user's MDM administrator.)
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335
Jan ’25
iOS 26: "TLS failed with error: -9808"
Our app server is having some TLS related issue with the new iOS 26 (It works with iOS 18 and below). When opening the domain url in iPhone Safari browser with iOS 26, it showing the error as below: We followed the instructions from this link (https://support.apple.com/en-sg/122756), to run the following command: nscurl --tls-diagnostics https://test.example in Terminal app. It shows TLS failed with error: -9808 Could anyone please help explain what exactly the issue is with our server certificate, and how we should fix it? Thanks so much!
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501
Sep ’25
Installing our app interferes with network connection in another app
Apologies if this is not the correct topic to post under. EpochField 5.2 is our application. It's a .NET MAUI application built against XCode 16. A customer of ours uses another app, TN3270, to connect to a mainframe host. After installing our app on an iPad and restarting the device, the TN3270 app will disconnect when suspended. Uninstalling our app (EpochField) will allow the TN3270 to suspend without disconnecting. We have tried removing background services, setting UIRequiresFullScreen to false or removing it entirely, and several other ideas. The only remedy seems to be uninstalling EpochField. On an iPad device: Install MochaSoft’s TN3270 app (free version is fine). Create a connection to ssl3270.nccourts.org, port 2023, SSL/TLS turned on, keep alive turned on. Verify that you can connect. Suspend the app by swiping up or choosing another app. Go back to TN3270 and verify that the app has not disconnected. Install EpochField 5.2. Do not run or configure the app, just install it. Repeat step 2. Restart the device. Open EpochField 5.2. You do not need to configure the app or login. Sometimes it isn't necessary to ever open EpochField to get the disconnects, but this is the most reliable way to reproduce the situation. Repeat step 2. The TN3270 app will now disconnect when suspended, even if EpochField is closed. You may need to wait a few seconds after suspending. Uninstall EpochField 5.2. Repeat step 2: the TN3270 app will now remain connected when suspended.
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204
1d
packet-tunnel-provider-systemextension doesn't work
I am currently creating a MacOS app that uses NetworkExtension and SystemExtension without going through the Store. Using entitlements, I manually codesign and create a pkg Installer, but when I run it I get an error message saying "No matching profile found." Below is the log /Applications/Runetale.app/Contents/MacOS/Runetale not valid: Error Domain=AppleMobileFileIntegrityError Code=-413 "No matching profile found" UserInfo={NSURL=file:///Applications/Runetale.app/, unsatisfiedEntitlements=<CFArray 0x71c040fa0 [0x1f7bec120]>{type = immutable, count = 3, values ​​= ( 0 : <CFString 0x71c04f340 [0x1f7bec120]>{contents = "com.apple.developer.system-extension.install"} 1 : <CFString 0x71c1ccaf0 [0x1f7bec120]>{contents = "com.apple.developer.networking.networkextension"} 2 : <CFString 0x71c04fc00 [0x1f7bec120]>{contents = "com.apple.developer.team-identifier"} )}, NSLocalizedDescription=No matching profile found} I looked into it myself and found that if you want to install the app without going through the Store, you need to use packet-tunnel-provider-systemextension instead of packet-tunnel-provider. here However, simply changing to packet-tunnel-provider-systemextension does not allow the build to pass. I use a build method that changes the value of entitlements only during codesign in order to pass the build. SYSEXT="$APP_BUNDLE/Contents/Library/SystemExtensions/com.runetale.desktop.PacketTunnel.systemextension" if [ -d "$SYSEXT" ]; then echo "Signing PacketTunnel system extension with entitlements..." cp macos/PacketTunnel/PacketTunnelRelease.entitlements macos/PacketTunnel/PacketTunnelRelease-sign.entitlements sed -i '' 's/packet-tunnel-provider/packet-tunnel-provider-systemextension/' macos/PacketTunnel/PacketTunnelRelease-sign.entitlements codesign --force --options runtime --timestamp --entitlements "$ENTITLEMENTS_FILE" --sign "$DEV_ID_APP_CERT" "$SYSEXT" fi # 3. Sign the entire .app bundle (deep sign by signing the outer app after inner ones) echo "Signing Runetale App with entitlements..." cp macos/Runner/Release.entitlements macos/PacketTunnel/Release-sign.entitlements sed -i '' 's/packet-tunnel-provider/packet-tunnel-provider-systemextension/' macos/PacketTunnel/Release-sign.entitlementsmacos/PacketTunnel/Release-sign.entitlements codesign --force --options runtime --timestamp --entitlements "$APP_ENTITLEMENTS_FILE" --sign "$DEV_ID_APP_CERT" "$APP_BUNDLE" Is this build method wrong? The next solution I'm thinking of is as follows. Is there a way to write packet-tunnel-provider-systemextension directly to entitlments and pass the build? (provisioning profile?) Apply to forum and get permission to use packet-tunnel-provider-systemextension Thank you.
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191
Apr ’25
On demand rules and Split tunnel
I've implemented a custom system extension VPN for macOS using Packet Tunnel Provider. The VPN is configured with on-demand, and a rule to always connect whenever there's traffic: onDemandRules = [NEOnDemandRuleConnect()] As for the tunnel's settings (at the Packet Tunnel Provider), I've configured a split tunnel, so some routes are excluded from the tunnel. Now I have the following scenario: The VPN is connected The Mac enters sleep The sleep() function is called (at my Packet Tunnel Provider) The Mac briefly awakes to check emails/push notifications/etc. This traffic is excluded from the tunnel. What is the expected behavior here? Should the wake function be called because of the on-demand rule? Or should the VPN remain asleep because this traffic is excluded from the tunnel?
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569
Feb ’25
macOS 26 (Tahoe) lacks Wi‑Fi Aware support — any roadmap or plans?
Hello all, WWDC 2025 introduced Wi‑Fi Aware (NAN) support on iOS 26 for peer-to-peer discovery and direct connections, but I noticed macOS Tahoe doesn’t include it. I couldn’t find any references to Wi‑Fi Aware APIs or framework support in the macOS SDK. Is Apple planning to bring Wi‑Fi Aware to macOS? If so, will this come in a future update to macOS 26 (e.g., 26.x), or is it deferred to macOS 27 or beyond? Thanks for any insights!
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2
279
Aug ’25
PacketTunnelProvider gets corrupted when app updated with connected Tunnel
We currently supporting proxy app with Tunnel.appEx and PacketTunnelProvider. Some users report about constant error "The VPN session failed because an internal error occurred." on VPN start (which fails rapidly). This error occur mostly after user updated app with active VPN. Rebooting device solves the problem and it doesnt come again, but it is still very frustrating. I can provide any required info about app setup to solve this issue if you need. Thanks
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1
189
Aug ’25
Cannot add VPN configuration on iOS 26 beta 5 when passcode is enabled
On iOS 26 beta 5, it is impossible to add a VPN configuration when a passcode is set on the device. Every time, all it does is redirect to the Settings app with no prompt for passcode. The only way around this is to disable passcode on the device so adding a VPN configuration doesn’t have to open the Settings app. This issue happened intermittently in the past with previous iOS 26 betas and even on iOS 18, but the problem has worsened on iOS 26 beta 5 to the point where you have to turn off passcode to add a VPN. Feedback ID: FB17974765
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8
4.4k
Aug ’25