Hi everyone, I’m working with UDP Multicasting on iOS (iOS 15+) using Network.framework and facing a confusing issue. Setup: Multicast IP: 239.255.0.1 Port: 45454 Using NWConnectionGroup / NWMulticastGroup NSLocalNetworkUsageDescription is present in Info.plist Devices are on the same Wi-Fi network Problem: Receiving multicast packets works perfectly Sending multicast packets does NOT work No errors are thrown send() completion handler reports success stateUpdateHandler sometimes doesn’t transition to .ready No packets are actually transmitted on the network Observations: The app can receive data from other multicast senders Sending appears to be silently blocked Reinstalling the app fixes the issue This points to a Local Network permission problem If permission was denied once, iOS does not re-prompt Inbound multicast works, outbound multicast is blocked Questions: Is it expected on iOS that receiving multicast works even when sending is blocked? Is reinstalling the app the only way to recover if Local Network permission was denied? Is there any reliable runtime way to detect that outbound multicast is blocked? Is NWConnectionGroup the correct and only supported way to send multicast on iOS? Any clarification or official guidance would really help. Thanks in advance!

Hi, I developed a network extension program on macOS. I tried to update the program by changing the version number. My update process was to first turn off network filtering via "NEFilterManager.sharedManager.enabled = NO", and then use "[OSSystemExtensionRequest activationRequestForExtension:bundleid queue:dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0)];" to let the system replace the old network extension program. However, sometimes the old network extension process will become a zombie process like pid=86621 in the figure. As long as the zombie process exists, the network cannot be used. After about 10 minutes, it will be cleared and the network will be available. Restarting Wi-Fi can also clear the zombie process immediately. Why is this? How to avoid this problem?

In my basement I have a couple of raspberry PIs that are collecting sensor data. They cannot send the data to any server because there is no signal in the basement. So my idea was to develop an app that would host a web server so that I can take my phone, go into the basement and enable the hotspot so that the raspberrys can connect to my phones Wifi and send their sensor data via API calls to the web server that is running on the phone. I have read about Vapor but somehow that feels like overkill for this problem. Do you guys have any recommendations how to solve this problem or better ideas than running a web server on the iPhone (and no, extending the wifi signal into the basement is not an option here)?

MacOS (15.7) local host (expressjs: light weight REST API server) NOT able to configure to access from my iPhone physically connected via thunderbolt BUT I am able to access it from localhost via Browser of the Macbook (locally), But NOT from iPhone server running at '0.0.0.0' Firewall is turned off(by default) I hope someone can get me the steps in enabling the port

Hi In the "CaptiveNetwork.h", the "CNCopyCurrentNetworkInfo" is marked as "API_TO_BE_DEPRECATED" CFDictionaryRef __nullable CNCopyCurrentNetworkInfo (CFStringRef interfaceName) API_DEPRECATED_WITH_REPLACEMENT("[NEHotspotNetwork fetchCurrentWithCompletionHandler:]", ios(4.1, API_TO_BE_DEPRECATED), macCatalyst(14.0, API_TO_BE_DEPRECATED)) API_UNAVAILABLE(macos, tvos, watchos, visionos); But in developer documents, it is marked as "DEPRECATED"： https://developer.apple.com/documentation/systemconfiguration/cncopycurrentnetworkinfo Before we use Xcode 16.2 to archive app, this interface still work on iOS 26 device. But after we changed to Xcode 26.2, this interface return nothing on iOS 26 and we need to use "NEHotspotNetwork" related interface. My question is： Why there are difference between the documents and framework sdk how we can know that a interface marked "API_TO_BE_DEPRECATED" or "DEPRECATED", when will they not work totally. Is there a accurate timeline or standard for them? Some interface marked deprecated after 12.0 is still working Now. After knowing the accurate timeline we can plan the interfaces migration.

Dear Team, We are trying to implement universal linking app to app redirection for our banking application. We have configured the associated domains in our application as can be seen below in the info plist of our IPA <?xml version="1.0" encoding="UTF-8"?><!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "https://www.apple.com/DTDs/PropertyList-1.0.dtd"><plist version="1.0"><dict><key>application-identifier</key><string>2TK5X82C47.com.bankalbilad.NewRMB</string><key>aps-environment</key><string>production</string><key>beta-reports-active</key><true/><key>com.apple.developer.associated-domains</key><array><string>applinks:rob-auth.bankalbilad.com</string></array><key>com.apple.developer.icloud-container-identifiers</key><array></array><key>com.apple.developer.pass-type-identifiers</key><array><string>2TK5X82C47.*</string></array><key>com.apple.developer.payment-pass-provisioning</key><true/><key>com.apple.developer.team-identifier</key><string>2TK5X82C47</string><key>com.apple.developer.ubiquity-kvstore-identifier</key><string>2TK5X82C47.com.bankalbilad.NewRMB</string><key>com.apple.security.application-groups</key><array><string>group.com.NewRMB</string></array><key>get-task-allow</key><false/><key>keychain-access-groups</key><array><string>2TK5X82C47.com.bankalbilad.NewRMB.keychain</string></array></dict></plist> We are unable to see the call made from IOS reaching the endpoint which is https://rob-auth.bankalbilad.com/.well-known/apple-app-site-association We performed curl of our domain and get the below error. curl -i https://app-site-association.cdn-apple.com/a/v1/rob-auth.bankalbilad.com HTTP/1.1 404 Not Found Server: AppleHttpServer/2caa77a6bc2e755fca0e0f63e4d67e53390f9184 Date: Thu, 14 May 2026 11:42:16 GMT Content-Type: text/plain; charset=utf-8 Content-Length: 10 Apple-Failure-Details: {"cause":"Connection failed"} Apple-Failure-Reason: SWCERR00305 Network error Apple-From: https://rob-auth.bankalbilad.com/.well-known/apple-app-site-association Apple-Try-Direct: false Cache-Control: max-age=3600,public Vary: Accept-Encoding X-B3-TraceId: bfafe8fa87a6828f Strict-Transport-Security: max-age=31536000 Age: 21 Via: https/1.1 defra2-vp-vst-017.ts.apple.com (acdn/302.16436), https/1.1 defra2-vp-vfe-006.ts.apple.com (acdn/302.16436), http/1.1 defra2-xdc-mx-023.ts.apple.com (acdn/302.16436), http/1.1 defra1-edge-fx-060.ts.apple.com (acdn/302.16436) X-Cache: hit-stale, hit-stale, hit-fresh, hit-fresh CDNUUID: 6fb88181-f58a-4059-a770-26a43e1f32d0-16071773867 Expires: Thu, 14 May 2026 11:42:26 GMT Connection: keep-alive Not Found curl -v https://app-site-association.cdn-apple.com/a/v1/rob-auth.bankalbilad.com * Host app-site-association.cdn-apple.com:443 was resolved. * IPv6: (none) * IPv4: 17.253.15.159, 17.253.63.204, 17.253.63.201, 17.253.29.140, 17.253.29.162, 17.253.39.133, 17.253.39.145, 17.253.15.162 * Trying 17.253.15.159:443... * schannel: disabled automatic use of client certificate * ALPN: curl offers http/1.1 * ALPN: server accepted http/1.1 * Connected to app-site-association.cdn-apple.com (17.253.15.159) port 443 * using HTTP/1.x > GET /a/v1/rob-auth.bankalbilad.com HTTP/1.1 > Host: app-site-association.cdn-apple.com > User-Agent: curl/8.13.0 > Accept: */* > < HTTP/1.1 404 Not Found < Server: AppleHttpServer/2caa77a6bc2e755fca0e0f63e4d67e53390f9184 < Date: Thu, 14 May 2026 11:42:16 GMT < Content-Type: text/plain; charset=utf-8 < Content-Length: 10 < Apple-Failure-Details: {"cause":"Connection failed"} < Apple-Failure-Reason: SWCERR00305 Network error < Apple-From: https://rob-auth.bankalbilad.com/.well-known/apple-app-site-association < Apple-Try-Direct: false < Cache-Control: max-age=3600,public < Vary: Accept-Encoding < X-B3-TraceId: bfafe8fa87a6828f < Strict-Transport-Security: max-age=31536000 < Age: 33 < Via: https/1.1 defra2-vp-vst-017.ts.apple.com (acdn/302.16436), https/1.1 defra2-vp-vfe-006.ts.apple.com (acdn/302.16436), http/1.1 defra2-xdc-mx-023.ts.apple.com (acdn/302.16436), http/1.1 defra1-edge-fx-058.ts.apple.com (acdn/302.16436) < X-Cache: hit-stale, hit-stale, hit-fresh, hit-fresh < CDNUUID: 77d7de5e-f827-44b1-bbf5-ae2d8e36e104-16053052830 < Expires: Thu, 14 May 2026 11:42:26 GMT < Connection: keep-alive We also don't see any blocks in our firewall or in WAF or any network level Load balancers. Can you please help in troubleshooting the same.

As part of the OpenJDK testing we run several regression tests, including for Java SE networking APIs. These APIs ultimately end up calling BSD socket functions. On macos, starting macos 26, including on recent 26.2 version, we have started seeing some unexplained but consistent exception from one of these BSD socket APIs. We receive a "ENOBUFS" errno (No buffer space available) when trying to construct a socket(). These exact same tests continue to pass on many other older versions of macos (including 15.7.x). After looking into this more, we have been able to narrow this down to a very trivial C code which is as follows (also attached): #include <stdio.h> #include <sys/socket.h> #include <string.h> #include <unistd.h> #include <sys/errno.h> static int create_socket(const int attempt_number) { const int fd = socket(AF_INET6, SOCK_STREAM, 0); if (fd < 0) { fprintf(stderr, "socket creation failed on attempt %d," " due to: %s\n", attempt_number, strerror(errno)); return fd; } return fd; } int main() { const unsigned int num_times = 250000; for (unsigned int i = 1; i <= num_times; i++) { const int fd = create_socket(i); if (fd < 0) { return -1; } close(fd); } fprintf(stderr, "successfully created and closed %d sockets\n", num_times); } The code very trivially creates a socket() and close()s it. It does this repeatedly in a loop for a certain number of iterations. Compiling this as: clang sockbufspaceerr.c -o sockbufspaceerr.o and running it as: ./sockbufspaceerr.o consistently generates an error as follows on macos 26.x: socket creation failed on attempt 160995, due to: No buffer space available The iteration number on which the socket() creation fails varies, but the issue does reproduce. Running the same on older versions of macos doesn't reproduce the issue and the program terminates normally after those many iterations. Looking at the xnu source that is made available for each macos release here https://opensource.apple.com/releases/, I see that for macos 26.x there have been changes in this kernel code and there appears to be some kind of memory accountability code introduced in this code path. However, looking at the reproducer/application code in question, I believe it uses the right set of functions to both create as well as release the resources, so I can't see why this should cause the above error in macos 26.x. Does this look like some issue that needs attention in the macos kernel and should I report it through feedback assitant tool?

Hi everyone, I'm developing an iOS app using Swift (Foundation, Network, and Combine) that communicates via TCP with a weighing scale. The scale uses an internal ESP32 module acting as a Wi-Fi Access Point (no internet access) specifically for data transmission. The app connects to this network and opens a socket to receive weight data and send command strings. I’m currently facing two main issues: Socket Management: The socket isn't closing properly. Occasionally, the app opens multiple simultaneous connections instead of maintaining a single one. Since the ESP32 has a client limit, these ghost connections eventually hang the communication module. Invalid Outbound Data: The connection drops frequently because the scale receives invalid strings from the app. My logs show strange character sequences (like "gggggggggfdhj" or "vfgdddddddddddtty") being sent involuntarily. I haven't programmed these strings, and they cause the scale to terminate the session due to protocol violations. How can I ensure proper socket closure and prevent these random data packets? Additionally, a technical question: Is it possible to keep this TCP connection active in the background indefinitely on iOS while the user interacts with other apps?

We have a VPN app that uses NEPacketTunnelProvider with includeAllNetworks = true. We've encountered an issue where push notifications are not delivered over Wi-Fi while the tunnel is active in a pre-MFA quarantine state (tunnel is up but traffic is blocked on server side), regardless of whether excludeAPNS is set to true or false. Observed behavior Wi-Fi excludeAPNS = true - Notifications not delivered Wi-Fi excludeAPNS = false - Notifications not delivered Cellular excludeAPNS = true - Notifications delivered Cellular excludeAPNS = false - Notifications not delivered On cellular, the behavior matches our expectations: setting excludeAPNS = true allows APNS traffic to bypass the tunnel and notifications arrive; setting it to false routes APNS through the tunnel and notifications are blocked (as expected for a non-forwarding tunnel). On Wi-Fi, notifications fail to deliver in both cases. Our question Is this expected behavior when includeAllNetworks is enabled on Wi-Fi, or is this a known issue / bug with APNS delivery? Is there something else in the Wi-Fi networking path that includeAllNetworks affects beyond routing, which could prevent APNS from functioning even when the traffic is excluded from the tunnel? Sample Project Below is the minimal code that reproduces this issue. The project has two targets: a main app and a Network Extension. The tunnel provider captures all IPv4 and IPv6 traffic via default routes but does not forward packets — simulating a pre-MFA quarantine state. The main app configures the tunnel with includeAllNetworks = true and provides a UI toggle for excludeAPNS. PacketTunnelProvider.swift (Network Extension target): import NetworkExtension class PacketTunnelProvider: NEPacketTunnelProvider { override func startTunnel(options: [String : NSObject]?, completionHandler: @escaping (Error?) -> Void) { let settings = NEPacketTunnelNetworkSettings(tunnelRemoteAddress: "127.0.0.1") let ipv4 = NEIPv4Settings(addresses: ["198.51.100.1"], subnetMasks: ["255.255.255.0"]) ipv4.includedRoutes = [NEIPv4Route.default()] settings.ipv4Settings = ipv4 let ipv6 = NEIPv6Settings(addresses: ["fd00::1"], networkPrefixLengths: [64]) ipv6.includedRoutes = [NEIPv6Route.default()] settings.ipv6Settings = ipv6 let dns = NEDNSSettings(servers: ["198.51.100.1"]) settings.dnsSettings = dns settings.mtu = 1400 setTunnelNetworkSettings(settings) { error in if let error = error { completionHandler(error) return } self.readPackets() completionHandler(nil) } } private func readPackets() { packetFlow.readPackets { [weak self] packets, protocols in self?.readPackets() } } override func stopTunnel(with reason: NEProviderStopReason, completionHandler: @escaping () -> Void) { completionHandler() } override func handleAppMessage(_ messageData: Data, completionHandler: ((Data?) -> Void)?) { if let handler = completionHandler { handler(messageData) } } override func sleep(completionHandler: @escaping () -> Void) { completionHandler() } override func wake() { } } ContentView.swift (Main app target) — trimmed to essentials: import SwiftUI import NetworkExtension struct ContentView: View { @State private var excludeAPNs = false @State private var manager: NETunnelProviderManager? var body: some View { VStack { Toggle("Exclude APNs", isOn: $excludeAPNs) .onChange(of: excludeAPNs) { Task { await saveAndReload() } } Button("Connect") { Task { await toggleVPN() } } } .padding() .task { await loadManager() } } private func loadManager() async { let managers = try? await NETunnelProviderManager.loadAllFromPreferences() if let existing = managers?.first { manager = existing } else { let m = NETunnelProviderManager() let proto = NETunnelProviderProtocol() proto.providerBundleIdentifier = "<your-extension-bundle-id>" proto.serverAddress = "127.0.0.1" proto.includeAllNetworks = true proto.excludeAPNs = excludeAPNs m.protocolConfiguration = proto m.localizedDescription = "TestVPN" m.isEnabled = true try? await m.saveToPreferences() try? await m.loadFromPreferences() manager = m } if let proto = manager?.protocolConfiguration as? NETunnelProviderProtocol { excludeAPNs = proto.excludeAPNs } } private func saveAndReload() async { guard let manager else { return } if let proto = manager.protocolConfiguration as? NETunnelProviderProtocol { proto.includeAllNetworks = true proto.excludeAPNs = excludeAPNs } manager.isEnabled = true try? await manager.saveToPreferences() try? await manager.loadFromPreferences() } private func toggleVPN() async { guard let manager else { return } if manager.connection.status == .connected { manager.connection.stopVPNTunnel() } else { await saveAndReload() try? manager.connection.startVPNTunnel() } } } Steps to reproduce Build and run the sample project with above code on a physical iOS device. Connect to a Wi-Fi network. Set excludeAPNS = true using the toggle and tap Connect. Send a push notification to the device to a test app with remote notification capability (e.g., via a test push service or the push notification console). Observe that the notification is not delivered. Disconnect. Switch to cellular. Reconnect with the same settings. Send the same push notification — observe that it is delivered. Environment iOS 26.2 Xcode 26.2 Physical device (iPhone 15 Pro)

Hi everyone, We are working on an app that requires access to devices on the local network (Bonjour / LAN discovery + direct socket communication). We are currently struggling with the Local Network privacy permission flow introduced by Apple. From our understanding, there is no dedicated public API to explicitly request Local Network permission or to reliably determine the current authorization state before attempting network activity. We have tried several commonly suggested approaches to trigger the permission dialog, including: Bonjour browsing via NWBrowser Publishing/listening with NetService UDP/TCP socket attempts on local subnet NWConnection / NWListener Triggering discovery after app launch and after foreground transitions We already added the required entries in: NSLocalNetworkUsageDescription NSBonjourServices However, the behavior is inconsistent across devices and OS versions: Sometimes the popup appears immediately Sometimes it never appears Sometimes network operations silently fail without callback clarity In some cases callbacks are delayed or ambiguous Reinstalling/resetting permissions changes behavior unpredictably Our main challenges are: What is currently considered the most reliable Apple-approved method to trigger the Local Network permission prompt? Is there any officially recommended way to determine whether permission is: not determined denied granted Is there any reliable callback or state transition API developers should use? Are there known differences between: NWBrowser NetService BSD sockets NWConnection when it comes to triggering the permission dialog? Are there recommended retry/timing patterns to avoid race conditions during app launch? Is Apple planning to introduce a dedicated authorization API similar to: AVAuthorizationStatus CLAuthorizationStatus PHPhotoLibrary.authorizationStatus() Right now it feels difficult to provide a reliable UX because there is no deterministic way to: proactively request access observe authorization state recover gracefully when the prompt does not appear Any guidance, DTS references, WWDC sessions, or recommended implementation patterns would be greatly appreciated. Thanks!

I want to track down which part of an app contacts a given domain listed in its App Privacy Report. Following the instructions given here I am able to capture a packet trace, but traffic to the domain in question is encrypted using QUIC. Is there a way to insert e.g. mitmproxy into the capture process in order to get hold of the SSLKEYLOGFILE so that I can decrypt the traffic?

Hello, I am working on a network security and DLP (Data Loss Prevention) solution. A core requirement of our architecture is the ability to modify network traffic payloads in-flight (e.g., stripping sensitive data or altering packets). So, the only way to implement this is via the NETransparentProxyProvider which allows us to handle, evaluate, and modify network flows (NEAppProxyFlow). However, because this is such a powerful mechanism, my primary goal is to ensure the absolute stability of the operating system. I want to minimize the risk of interfering with core Apple services. When evaluating a flow, I have access to NEFlowMetaData, specifically properties like sourceAppUniqueIdentifier and sourceAppAuditToken. Could you please assist me with the following questions: Is there a recommended list of Apple system Application IDs (Bundle IDs) or executable names that should be strictly bypassed (ignored) by the Network Extension to maintain system integrity? Since system daemons can change between OS releases, are there any programmatic best practices or specific rules to dynamically identify core OS traffic that must not be intercepted? Are there any specific network ports or protocols that Apple strongly recommends excluding from NENetworkRule matches at the proxy provider configuration level to ensure daemons like apsd or mDNSResponder function correctly? Thank you in advance.

Hi We are building a VPN app (PacketTunnelProvider) and allowing users to install the app through test flight and app upgrade works seamlessly without VPN, but immediately after enabling the VPN, we are not able to get app upgraded with the progress bar in test flight stuck at 90 percent and now app is not usable after that but VPN is still working. We are not noticing the issue on ios 12.4.1 version but facing the issue on iOS 13 versions. On looking through console app during upgradation process we are noticing a below recurring log message. Error acquiring hold on plugins for &lt;bundle_identifier&gt;: Error Domain=PlugInKit Code=14 "plugins are busy" UserInfo={busyPlugInUUIDs=({         XPCExtensionBundleIdentifier = "&lt;bundle_identifier&gt;.tunnel";     } ), NSLocalizedDescription=plugins are busy} Could someone please help us in resolving the issue.

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 TCP and UDP ports used by Apple software products support article 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. WWDC 2025 Session 314 Get ahead with quantum-secure cryptography 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. Prepare your network environment for stricter security requirements support article — This is primarily of interest to folks developing management software, for example, an MDM server. 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.

Is there any iOS API, framework, or entitlement (public or beta) that lets an app detect when a user disables or removes a Configuration Profile (specifically a DNS-over-HTTPS profile) — without VPN extension, MDM, or supervised mode? Use case: I need to know server-side, in real time, when the user toggles off a .mobileconfig DoH profile they previously installed. Things I've already reviewed and ruled out: NetworkExtension (NEDNSSettingsManager — only fires while app is running) BGTaskScheduler (iOS-scheduled, not real-time) NEFilterDataProvider (requires supervised) VPN / MDM / supervised Anything I'm missing?

According to documentation, the URLSession background tasks continue even when the app is suspended. What is the lifespan of the URLSessionDownloadDelegate object when app is suspended or terminated? Will it get re-created and re-initialize properties when the app re-launches, or will it somehow restore the existing property values? Also, urlSessionDidFinishEvents not getting called, and what do we need to do there with the backgroundCompletionHandler? Any insights are much appreciated. We are getting ready to launch and this is a roadblock. (visionOS26.4) Thank you. @Observable class DownloadManager: NSObject, URLSessionDownloadDelegate { ... let config = URLSessionConfiguration.background(withIdentifier: "TestDL") config.sessionSendsLaunchEvents = true var urlSession = URLSession(configuration: config, delegate: self, delegateQueue: nil) func downloadFiles(... { // initiate multiple file downloads concurrently for url in urlList { let task = urlSession.downloadTask(with: url) task.resume() } } func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) { ... func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) { ... func urlSession(_: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) { ... // Not getting called ?? // Is this only called when app is suspended/terminated? func urlSessionDidFinishEvents(forBackgroundURLSession session: URLSession) { print("didFinishEvents") Task { @MainActor in //urlSession?.finishTasksAndInvalidate() //urlSession = nil // not sure what to do here: if let appDelegate = UIApplication.shared.delegate as? AppDelegate, let completionHandler = appDelegate.backgroundCompletionHandler { completionHandler() appDelegate.backgroundCompletionHandler = nil } } }

Summary We are activating a Network Extension system extension (filter-data) from a signed and notarized macOS app. Activation consistently fails with: OSSystemExtensionErrorDomain code=4 Extension not found in App bundle. Unable to find any matched extension with identifier: com.seaskylight.yksmacos.ExamNetFilter.data At the same time, sysextd logs: no policy, cannot allow apps outside /Applications However, our host app and executable real paths are already under /Applications, and the extension bundle physically exists in the expected app bundle location. Environment macOS: Darwin 25.4.0 Host app: /Applications/xxx.app Host bundle id: com.seaskylight.yksmacos System extension bundle id: com.seaskylight.yksmacos.ExamNetFilter.data Team ID: BVU65MZFLK Device management: Enrolled via DEP: No MDM enrollment: No Reproduction Steps Install host app to /Applications. Launch host app via Finder or: open -a "/Applications/xxx.app" Trigger OSSystemExtensionRequest activationRequestForExtension for: com.seaskylight.yksmacos.ExamNetFilter.data Observe failure callback (code=4). Collect logs: log show --last 2m --style compact --info --debug --predicate 'process == "sysextd"' systemextensionsctl list (shows 0 extension(s)) Observed Results sysextd client activation request for com.seaskylight.yksmacos.ExamNetFilter.data attempting to realize extension with identifier com.seaskylight.yksmacos.ExamNetFilter.data no policy, cannot allow apps outside /Applications App-side diagnostics (captured at failure) pid=3249 bundlePath=/Applications/xxx.app bundlePathReal=/Applications/xxx.app execPath=/Applications/xxx.app/Contents/MacOS/xxx execPathReal=/Applications/xxx.app/Contents/MacOS/xxx extPath=/Applications/xxx.app/Contents/Library/SystemExtensions/ExamNetFilterData.systemextension extExists=true runningFromHelper=false Error callback NSError{domain=OSSystemExtensionErrorDomain code=4 desc=Extension not found in App bundle...} Additional Validation We reproduced the same failure using a minimal native host app (SysExtProbe) in /Applications that only submits the activation request for the same extension identifier. It also fails with OSSystemExtensionErrorDomain code=4, indicating this is not specific to Electron app logic. Signing / Packaging Notes Host app and system extension are signed with the same Team ID (BVU65MZFLK). System extension bundle exists under: /Applications/xxx.app/Contents/Library/SystemExtensions/ExamNetFilterData.systemextension Extension Info.plist contains bundle id: com.seaskylight.yksmacos.ExamNetFilter.data Host app includes NSSystemExtensionUsageDescription. Questions for DTS In non-MDM personal-device scenarios, what exact conditions trigger sysextd to emit: no policy, cannot allow apps outside /Applications even when both bundlePath and realpath are in /Applications? Can code=4 (“Extension not found in App bundle”) be returned for policy/state reasons even when extension bundle is present and identifier matches? Are there known sysextd policy/cache states that cause this behavior, and what is the recommended recovery procedure?

Post app update our extension version is replaced with the new version. However occasionally maybe around 20% of the time The XPC connection we have for communication between the app and extension will not work. We have reconnection retry logic as well as tried stop and starting the extension but it appears once its broken its broken and all that fixes it is a machine restart. This is obviously not ideal. I have noticed a few other forums talking about the same or similar problem. https://developer.apple.com/forums/thread/728063 https://developer.apple.com/forums/thread/779395 https://developer.apple.com/forums/thread/742992 When we run on a broken upgrade cycle `sudo launchctl print system/NetworkExtension.com.company.example.app.filter.5.5.0.2248 ` We notice that endpoints is missing from the log. However if we run the same command in terminal for a working upgrade cycle endpoints = {} exist. Therefore for some reason our xpc isn't actually getting registered.

Hello, I am investigating a recurring crash that appears to be originating within the system's network stack. OS Version: iPhone OS 26.1 (23B85) Role: Foreground Exception Type: EXC_BAD_ACCESS (SIGSEGV) Exception Subtype: KERN_INVALID_ADDRESS at 0x0000000000000000 Exception Codes: 0x0000000000000001, 0x0000000000000000 Triggered by Thread: 19 Description: The crash is triggered by Thread 19 and occurs deep within libquic.dylib during a QUIC recovery timer event. Based on the backtrace, the failure happens in quic_recovery_pto. The issue seems to occur when a protocol instance schedules a wakeup, leading to a null pointer dereference in the system library. Crashed Thread Backtrace snippet:Thread 19 Crashed: Thread 19 Crashed: 0 libquic.dylib 0x00000001a00a38cc quic_recovery_pto + 72 (quic_recovery.c:1259) 1 libquic.dylib 0x00000001a00a3390 quic_recovery_timer_fired + 132 (quic_recovery.c:1460) 2 libquic.dylib 0x00000001a00a1f8c quic_timer_run + 248 (quic_timer.c:210) 3 Network 0x000000018ec76cbc __nw_protocol_instance_schedule_wakeup_block_invoke + 76 (protocol_implementation.cpp:5847) 4 Network 0x000000018eba34e0 __nw_context_reset_timer_block_with_time_block_invoke + 268 (context.cpp:2224) 5 libdispatch.dylib 0x00000001c84727ec _dispatch_client_callout + 16 (client_callout.mm:85) 6 libdispatch.dylib 0x00000001c845d664 _dispatch_continuation_pop + 596 (queue.c:349) 7 libdispatch.dylib 0x00000001c8470528 _dispatch_source_latch_and_call + 396 (source.c:601) 8 libdispatch.dylib 0x00000001c846f1fc _dispatch_source_invoke + 844 (source.c:966) 9 libdispatch.dylib 0x00000001c8463288 _dispatch_workloop_invoke + 1612 (queue.c:4761) 10 libdispatch.dylib 0x00000001c846c3ec _dispatch_root_queue_drain_deferred_wlh + 292 (queue.c:7265) 11 libdispatch.dylib 0x00000001c846bce4 _dispatch_workloop_worker_thread + 692 (queue.c:6859) 12 libsystem_pthread.dylib 0x00000001ec0623b8 _pthread_wqthread + 292 (pthread.c:2696) 13 libsystem_pthread.dylib 0x00000001ec0618c0 start_wqthread + 8 (:-1) Can anyone provide insights into what might be causing libquic to access an invalid address in this context? Any help or suggestions for further diagnostics would be greatly appreciated.

I've searched these terms all over the place and have found only a confusing mishmash of things that were probably true years ago but no longer seem to reflect today's reality so I'm posting it here to hopefully add a definitive 2026 answer to these search results for myself and others. The existence of the DNS Proxy Network Extension protocol in 10.15 has given me an idea. I would like to test this idea to see if it is worth developing further or a complete waste of time. This test does not need to run on any device anywhere in the world other than the one in front of me so I would prefer not to spend $100 just to see if I can make a small code fragment do a silly trick. XCode sadly refuses to build my Network Extension target when I only have a "Personal Team" to sign with: Personal development teams, including "XXXX XXXX", do not support the Network Extensions capability. Can this be done or is Apple just 100% pay-to-play nowadays? I have zero problems disabling SIPS or any other consumer grade protections if that will actually achieve my goal but I've read enough comments from people saying it didn't work that I haven't bothered trying. Thanks for reading. OS: 15.7.5 (24G624) XCode Version 26.3 (17C529)