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.

Summary On macOS 26.4.1 (25E253), iCloud Drive file uploads can enter a silent deadlock where every upload attempt fails at the transport layer. No error is surfaced anywhere — not in Finder, not in System Settings, not in the iCloud status panel. The upload queue simply stops. Other iCloud services (Photos, Mail, App Store) continue to work normally through the same networking infrastructure at the same time. Root Cause The issue is a stale HTTP/3 (QUIC) session cached in the user-level nsurlsessiond process's BackgroundConnectionPool. The deadlock cycle: cloudd requests an upload to the GCS storage endpoint nsurlsessiond provides the cached (broken) HTTP/3 session The TLS handshake succeeds, but the body upload dies mid-transfer (err=T, requestDuration=-1.000, responseHeaderBytes=0) cloudd retries with a new connectionUUID — but nsurlsessiond still routes through the same poisoned QUIC session This repeats indefinitely Killing cloudd alone does not help — nsurlsessiond retains the poisoned pool. Only killing both the user-level cloudd and nsurlsessiond clears the pool and forces a fresh protocol negotiation. The Smoking Gun After killing both daemons, the system falls back to HTTP/1.1 for the stuck uploads — and they complete instantly: Before Kill After Kill Protocol h3 (QUIC) http/1.1 (TCP) Largest upload Failed at partial offsets 26 MB in 1.6 seconds Server response 0 bytes 596 bytes (normal) Same endpoint, same files, same network interface (en5), same power state. The only change was the protocol negotiation after a fresh nsurlsessiond. Reproduction Reproduced 3 times on April 11, 2026 using a standardized set of 8 test files (8 bytes to 20 MB) in a non-shared iCloud Drive folder. Each run showed the identical pattern: Small files (<100 KB) squeeze through before the QUIC session stalls Larger files trigger the deadlock every time 5–6 retries with fresh connectionUUIDs, all failing over protocol=h3 After kill cloudd + nsurlsessiond: immediate flush via protocol=http/1.1 An automated evidence-collection script (collect_h3_deadlock_evidence.sh) captures paired before-kill / after-kill logs. Included in the Feedback report. Symptom Check (for others hitting this) /usr/bin/log show --predicate 'process == "cloudd"' --last 5m 2>&1 \ | grep "putContainer.*err=T.*requestDuration=-1.000.*protocol=h3" | wc -l Output > 0 = this deadlock. Output = 0 = different issue. Recovery (one-liner) kill $(ps -axo user,pid,command | awk -v u="$USER" \ '($1==u && /CloudKitDaemon.framework.*cloudd/ && !/--system/) \ || ($1==u && /\/usr\/libexec\/nsurlsessiond/ && !/--privileged/) \ {print $2}') Both daemons respawn within 1–2 seconds. Do not use killall nsurlsessiond — it would also kill the privileged system instance. What was ruled out Network connectivity (Photos uploaded 8 MB through the same pool simultaneously) iCloud account (metadata operations succeeding, only body uploads failing) File type/content (random data, correlation is with size, not type) Storage quota (1.65 TB free) CFNetworkHTTP3Enabled=false (key is ineffective in 26.4.1) Suggested fixes (from the Feedback report) CFNetwork: Invalidate the QUIC session after N consecutive requestDuration=-1.000 failures CloudKit/NSURLSession: Expose a pool invalidation API like [NSURLSession invalidatePoolEntryForEndpoint:] cloudd: Self-healing retry — create a fresh NSURLSession after M consecutive deadlock-signature failures Finder: At minimum, surface the stuck state to the user instead of failing silently Filed as FB22476701 — includes full reproduction timelines, request/connection UUIDs, sysdiagnose, and a 12-page investigation PDF with architecture diagrams and protocol comparison tables. If you're experiencing the same issue, please file a duplicate referencing FB22476701 — Apple prioritizes by duplicate count. System MacBook Air, macOS 26.4.1 (25E253) iCloud Drive with Desktop & Documents sync en0 (WLAN) + en5 (USB-LAN via Studio Display)

How do I make a basic request with URLSession? See https://stackoverflow.com/questions/30573898 for reference. Also https://developer.apple.com/documentation/ has details.

URLSession question

I'm encountering a null pointer dereference crash pointing to the internals of CFNetwork library code on iOS. I'm spawning URLSessionTasks at a decently fast rate (~1-5 per second), with the goal being to generate application layer network traffic. I can reliably encounter this crash pointing to NetConnection::dequeue right after a new task has been spawned and had the resume method called. I suspect that this is perhaps a race condition or some delegate/session object lifecycle bug. The crash appears to be more easily reproduced with a higher rate of spawning URLSessionTasks. I've included the JSON crash file, the lldb stack trace, and the source code of my URLSession(Task) usage. urlsession_stuff_stacktrace.txt urlsession_stuff_source.txt urlsession_crash_report.txt

com.apple.main-thread 0 StarMaker 0x5c40854 _isPlatformVersionAtLeast.cold.2 + 4425680980 1 StarMaker 0x526d278 -[FPRScreenTraceTracker displayLinkStep] + 191 (FPRScreenTraceTracker.m:191) 2 QuartzCore 0xbe924 CA::Display::DisplayLinkItem::dispatch(CA::SignPost::Interval<(CA::SignPost::CAEventCode)835322056>&) + 64 3 QuartzCore 0x9bf38 CA::Display::DisplayLink::dispatch_items(unsigned long long, unsigned long long, unsigned long long) + 880 4 QuartzCore 0xaf770 CA::Display::DisplayLink::dispatch_deferred_display_links(unsigned int) + 360 5 UIKitCore 0x7dee4 _UIUpdateSequenceRunNext + 128 6 UIKitCore 0x7d374 schedulerStepScheduledMainSectionContinue + 60 7 UpdateCycle 0x1560 UC::DriverCore::continueProcessing() + 84 8 CoreFoundation 0x164cc __CFMachPortPerform + 168 9 CoreFoundation 0x460b0 CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION + 60 10 CoreFoundation 0x45fd8 __CFRunLoopDoSource1 + 508 11 CoreFoundation 0x1dc1c __CFRunLoopRun + 2168 12 CoreFoundation 0x1ca6c _CFRunLoopRunSpecificWithOptions + 532 13 GraphicsServices 0x1498 GSEventRunModal + 120 14 UIKitCore 0x9ddf8 -[UIApplication _run] + 792 15 UIKitCore 0x46e54 UIApplicationMain + 336 16 StarMaker 0x50c965c main + 18 (main.m:18) 17 ??? 0x19a9dae28 (缺少) Thread 0 libsystem_kernel.dylib 0x67f4 __semwait_signal + 8 1 libsystem_c.dylib 0xc7e4 nanosleep + 220 2 ZorroRtcEngineKit 0x1eb0f8 std::__Cr::this_thread::sleep_for(std::__Cr::chrono::duration<long long, std::__Cr::ratio<1l, 1000000000l>> const&) + 198 (pthread.h:198) 3 ZorroRtcEngineKit 0x27d30 zorro::KbLog::Loop() + 88 (kblog.cc:88) 4 ZorroRtcEngineKit 0x286e8 <deduplicated_symbol> + 4667967208 5 libsystem_pthread.dylib 0x444c _pthread_start + 136 6 libsystem_pthread.dylib 0x8cc thread_start + 8 Thread 0 libsystem_kernel.dylib 0x67f4 __semwait_signal + 8 1 libsystem_c.dylib 0xc7e4 nanosleep + 220 2 ZorroRtcEngineKit 0x1eb0f8 std::__Cr::this_thread::sleep_for(std::__Cr::chrono::duration<long long, std::__Cr::ratio<1l, 1000000000l>> const&) + 198 (pthread.h:198) 3 ZorroRtcEngineKit 0x19a4e4 zorro::ZkbLog::Loop() + 157 (zlog.cc:157) 4 ZorroRtcEngineKit 0x286e8 <deduplicated_symbol> + 4667967208 5 libsystem_pthread.dylib 0x444c _pthread_start + 136 6 libsystem_pthread.dylib 0x8cc thread_start + 8 Thread 0 libsystem_kernel.dylib 0x67f4 __semwait_signal + 8 1 libsystem_c.dylib 0xc7e4 nanosleep + 220 2 ZorroRtcEngineKit 0x1eb0f8 std::__Cr::this_thread::sleep_for(std::__Cr::chrono::duration<long long, std::__Cr::ratio<1l, 1000000000l>> const&) + 198 (pthread.h:198) 3 ZorroRtcEngineKit 0x19c4d8 zorro::QosManager::Loop() + 966 (string:966) 4 ZorroRtcEngineKit 0x286e8 <deduplicated_symbol> + 4667967208 5 libsystem_pthread.dylib 0x444c _pthread_start + 136 6 libsystem_pthread.dylib 0x8cc thread_start + 8

We are developing a watchOS application that records long audio sessions and uploads them to our backend in chunks (~5 MB each) using pre-signed URLs and URLSession background upload. Current behavior: While audio recording is active, uploads continue successfully even when the app is in the background. Once the recording stops, if multiple chunks (e.g., 10+) are still pending, the remaining uploads do not proceed in the background and appear to be suspended. We attempted to use WKExtendedRuntimeSession (mindfulness type) to allow sufficient time to enqueue background upload tasks, but the session is invalidated when the app goes to the background (e.g., wrist down or app inactive), which prevents reliable scheduling of uploads. Additionally, we added the entitlement: com.apple.developer.extended-runtime-session (mindfulness) in the Watch app entitlements file, but Xcode automatic signing fails with: “Provisioning profile does not include the com.apple.developer.extended-runtime-session entitlement.” It appears that the provisioning profile is not being updated to include this entitlement. Our questions: Is WKExtendedRuntimeSession (mindfulness) expected to support scheduling background URLSession uploads after the app goes to background? How should we reliably complete pending background uploads on watchOS after a long recording session ends? Is there any additional entitlement or recommended approach for this use case? Why is the extended runtime entitlement not being applied to the provisioning profile despite being added in the entitlements file? We are aiming to follow Apple-recommended practices for long-running tasks and background uploads on watchOS. Any guidance would be greatly appreciated.

Hello there, Starting from iOS 18.4, support was included for QWAC Validation and QCStatements. Using the official QWAC Validator at: https://eidas.ec.europa.eu/efda/qwac-validation-tool I was able to check that the domain "eidas.ec.europa.eu" has a valid QWAC certificate. However, when trying to obtain the same result using the new API, I do not obtain the same result. Here is my sample playground code: import Foundation import Security import PlaygroundSupport PlaygroundPage.current.needsIndefiniteExecution = true @MainActor class CertificateFetcher: NSObject, URLSessionDelegate { private let url: URL init(url: URL) { self.url = url super.init() } func start() { let session = URLSession(configuration: .ephemeral, delegate: self, delegateQueue: nil) let task = session.dataTask(with: url) { data, response, error in if let error = error { print("Error during request: \(error)") } else { print("Request completed.") } } task.resume() } nonisolated func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -&gt; Void) { guard let trust = challenge.protectionSpace.serverTrust else { completionHandler(.cancelAuthenticationChallenge, nil) return } if let certificates = SecTrustCopyCertificateChain(trust) as? [SecCertificate] { self.checkQWAC(certificates: certificates) } let credential = URLCredential(trust: trust) completionHandler(.useCredential, credential) } nonisolated func checkQWAC(certificates: [SecCertificate]) { let policy = SecPolicyCreateSSL(true, nil) var trust: SecTrust? guard SecTrustCreateWithCertificates(certificates as CFArray, policy, &amp;trust) == noErr, let trust else { print("Unable to create SecTrust") return } var error: CFError? guard SecTrustEvaluateWithError(trust, &amp;error) else { print("Trust evaluation failed") return } guard let result = SecTrustCopyResult(trust) as? [String : Any] else { print("No result dictionary") return } let qwacStatus = result[kSecTrustQWACValidation as String] let qcStatements = result[kSecTrustQCStatements as String] print("QWAC Status: \(String(describing: qwacStatus))") print("QC Statements: \(String(describing: qcStatements))") } } let url = URL(string: "https://eidas.ec.europa.eu/")! let fetcher = CertificateFetcher(url: url) fetcher.start() Which prints: QWAC Status: nil QC Statements: nil Request completed. Am I making a mistake while using the Security framework? I would greatly appreciate any help or guidance you can provide.

I am referencing: https://developer.apple.com/documentation/foundation/pausing-and-resuming-uploads Specifically: You can’t resume all uploads. The server must support the latest resumable upload protocol draft from the HTTP Working Group at the IETF. Also, uploads that use a background configuration handle resumption automatically, so manual resuming is only needed for non-background uploads. I have control over both the app and the server, and can't seem to get it to work automatically with a background url session. In other words, making multiple requests to get the offset then upload, easy but I am trying to leverage this background configuration resume OS magic. So anyone know what spec version does the server/client need to implement? The docs reference version 3, however the standard is now at like 11. Of course, I am trying out 3. Does anyone know how exactly this resume is implemented in iOS, and what exactly it takes care of? I assumed that I can just POST to a generic end point, say /files, then the OS receives a 104 Location, and saves that. If the upload is interrupted, when the OS resumes the upload, it has enough information to figure out how to resume from the exact offset, either by making a HEAD request to get the offset, or handle a 409. I am assuming it does this, as if it doesn't, the 'uploads that use a background configuration handle resumption automatically' is useless, if it just restarts from 0. Note, of course making individual POST/HEAD/PATCH requests manually works, but at that point I'm not really leveraging any OS auto-magic, and am just consuming an API that could really implement any spec. This won't work in the background, as the OS seems to disallow random HTTP requests when it wakes the app for URLSession background resumes. As of right now, I have it 'partially' working, insofar as the app does receive the 104 didReceiveInformationalResponse url delegate call, however it seems to then hang; it stops sending bytes, seemingly when the 104 is received. However, the request does not complete. In other words, it doesn't seem to receive a client timeout or otherwise indicate the request has finished. Right now, I am starting a single request, POSTing to a /files end point, i.e. I am not getting the location first, then PATCHing to that, as if I do that, the OS 'automatic' resuming fails with a 409, i.e. it doesn't seem to make a HEAD request and/or use the 409 offset correction then continue with the PATCH. Any idea what could be going on?

Hi， Apps crashed when GCDAsyncSocket closeWithError，since iOS 16 。 Crash stack like this： Hardware Model: iPhone10,1 Code Type: ARM-64 (Native) Parent Process: [1] Date/Time: 2022-06-09 08:59:02.201 +0800 OS Version: 16.0 (20A5283p) Report Version: 104 Last Exception : 0 libsystem_platform.dylib 0x000000021bc1f08c 0x000000021bc19000 + 24716 1 libsystem_platform.dylib 0x000000021bc19898 0x000000021bc19000 + 2200 2 CoreFoundation 0x00000001a4dfa3e0 CFSocketInvalidate + 132 3 CFNetwork 0x00000001a5667830 _CFNetworkErrorGetLocalizedDescription + 307856 4 CoreFoundation 0x00000001a4d55f4c CFArrayApplyFunction + 72 5 CFNetwork 0x00000001a56453ac _CFNetworkErrorGetLocalizedDescription + 167436 6 CoreFoundation 0x00000001a4d5d118 0x00000001a4d49000 + 82200 7 CoreFoundation 0x00000001a4dfa718 CFSocketInvalidate + 956 8 CFNetwork 0x00000001a5651e84 _CFNetworkErrorGetLocalizedDescription + 219364 9 CoreFoundation 0x00000001a4d631d4 0x00000001a4d49000 + 106964 10 *** 0x000000010c1bc490 -[GCDAsyncSocket closeWithError:] + 260 11 *** 0x000000010c1c0b54 -[GCDAsyncSocket doReadEOF] + 360 12 *** 0x000000010c1bf1fc __69-[GCDAsyncSocket setupReadAndWriteSourcesForNewlyConnectedSocket:]_block_invoke + 88 13 libdispatch.dylib 0x00000001a4a330f4 0x00000001a4a2f000 + 16628 14 libdispatch.dylib 0x00000001a4a36584 0x00000001a4a2f000 + 30084 15 libdispatch.dylib 0x00000001a4a49b04 0x00000001a4a2f000 + 109316 16 libdispatch.dylib 0x00000001a4a3a684 0x00000001a4a2f000 + 46724 17 libdispatch.dylib 0x00000001a4a3b2f8 0x00000001a4a2f000 + 49912 18 libdispatch.dylib 0x00000001a4a45ebc 0x00000001a4a2f000 + 93884 19 libsystem_pthread.dylib 0x000000021bc210a8 _pthread_wqthread + 288

We are currently experiencing an issue that occurs only on iPhone 17 models. In our app, after connecting to an external device, users can download multiple video files stored on the device. When downloading several videos consecutively, the device consistently stops receiving responses midway through the process. As a result, no response is returned, and the connection between the app and the device is eventually lost. This issue does not occur on any iPhone models prior to iPhone 17. It is reproducible across all iPhone 17 devices within our company. This is a critical issue, and we need urgent assistance. The main error logs show two patterns: • Connection loss • Timeout At the OS level, the only error codes we receive are: • -1005 (Network connection lost) • -1001 (Request timed out) Unfortunately, we are unable to obtain more detailed error information beyond these codes, which makes further debugging difficult. We have attached the relevant logs below. We would greatly appreciate any guidance on how to further investigate or resolve this issue. 310.0 / :: 81 % ::: 251.21481481481482 310.0 / :: 82 % ::: 254.23280423280423 310.0 / :: 83 % ::: 257.3820105820106 310.0 / :: 84 % ::: 260.4 KeepAlive SEND id=423F1336-6239-4B3B-9414-5A987D85D564 at=2026-02-24T12:56:43Z timeout=60.000000s current: D20-Q2-PLUS, ssid: D20-Q2-PLUS_136a63 KeepAlive SKIP (in-flight) tcp_output [C10.1.1:3] flags=[R.] seq=4017430266, ack=4146413113, win=2048 state=CLOSED rcv_nxt=4146413113, snd_una=4017429847 nw_read_request_report [C10] Receive failed with error "Operation timed out" nw_flow_add_write_request [C10 192.168.000.0:443 failed parent-flow (satisfied (Path is satisfied), interface: en0[802.11], ipv4, dns, uses wifi, LQM: good)] cannot accept write requests nw_write_request_report [C10] Send failed with error "Socket is not connected" Task <5BDBE621-329A-45E9-B236-9C173E92A41F>.<7> HTTP load failed, 361/0 bytes (error code: -1005 [4:-4]) Task <5BDBE621-329A-45E9-B236-9C173E92A41F>.<7> finished with error [-1005] Error Domain=NSURLErrorDomain Code=-1005 "The network connection was lost." UserInfo={_kCFStreamErrorCodeKey=-4, NSUnderlyingError=0x13e632160 {Error Domain=kCFErrorDomainCFNetwork Code=-1005 "(null)" UserInfo={NSErrorPeerAddressKey=<CFData 0x14cfe5a90 [0x201746068]>{length = 16, capacity = 16, bytes = 0x100201bbc0a86f010000000000000000}, _kCFStreamErrorCodeKey=-4, _kCFStreamErrorDomainKey=4}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <5BDBE621-329A-45E9-B236-9C173E92A41F>.<7>, _NSURLErrorRelatedURLSessionTaskErrorKey=( "LocalDataTask <5BDBE621-329A-45E9-B236-9C173E92A41F>.<7>" ), NSLocalizedDescription=The network connection was lost., NSErrorFailingURLStringKey=https://192.168.000.0/keepalive, NSErrorFailingURLKey=https://192.168.000.0/keepalive, _kCFStreamErrorDomainKey=4} KeepAlive FAIL id=423F1336-6239-4B3B-9414-5A987D85D564 elapsed=29.203s status=-1 error=Optional(Alamofire.AFError.sessionTaskFailed(error: Error Domain=NSURLErrorDomain Code=-1005 "The network connection was lost." UserInfo={_kCFStreamErrorCodeKey=-4, NSUnderlyingError=0x13e632160 {Error Domain=kCFErrorDomainCFNetwork Code=-1005 "(null)" UserInfo={NSErrorPeerAddressKey=<CFData 0x14cfe5a90 [0x201746068]>{length = 16, capacity = 16, bytes = 0x100201bbc0a86f010000000000000000}, _kCFStreamErrorCodeKey=-4, _kCFStreamErrorDomainKey=4}}, ), NSLocalizedDescription=The network connection was lost., KeepAlive FAIL 1001 Log KeepAlive SEND id=FC433405-C1F7-47EF-AF9E-D12E67B071FA at=2026-02-24T12:22:38Z timeout=60.000000s current: D20-Q2-PLUS, ssid: VUEROID_D20-Q2-PLUS_136a63 KeepAlive FAIL id=FC433405-C1F7-47EF-AF9E-D12E67B071FA elapsed=7.834s status=-1 error=Optional(Alamofire.AFError.sessionTaskFailed(error: Error Domain=NSURLErrorDomain Code=-1001 "The request timed out." UserInfo={_kCFStreamErrorCodeKey=60, NSUnderlyingError=0x135e612f0 {Error Domain=kCFErrorDomainCFNetwork Code=-1001 "(null)" UserInfo={_NSURLErrorNWPathKey=satisfied (Path is satisfied), viable, interface: en0[802.11], ipv4, dns, uses wifi, LQM: good, _kCFStreamErrorCodeKey=60, _kCFStreamErrorDomainKey=1}}, ), NSLocalizedDescription=The request timed out., NSErrorFailingURLKey=https://192.168.000.0/keepalive, _kCFStreamErrorDomainKey=1})) KeepAlive FAIL ignored count=1 error=Server error : Optional(Alamofire.AFError.sessionTaskFailed(error: Error Domain=NSURLErrorDomain Code=-1001 "The request timed out." UserInfo={_kCFStreamErrorCodeKey=60, KeepAlive SEND id=A64AE4C0-28B4-41E3-AAC9-422C41D99D15 at=2026-02-24T12:22:58Z timeout=60.000000s KeepAlive FAIL id=110B96DA-4D88-45E0-B8F7-D0A9798593AE elapsed=43.605s status=-1 error=Optional(Alamofire.AFError.sessionTaskFailed(error: Error Domain=NSURLErrorDomain Code=-1005 "The network connection was lost." UserInfo={_kCFStreamErrorCodeKey=-4, NSUnderlyingError=0x135e60f60 {Error Domain=kCFErrorDomainCFNetwork Code=-1005 "(null)" UserInfo={NSErrorPeerAddressKey=<CFData 0x144dfee40 [0x201746068]>{length = 16, capacity = 16, bytes = 0x100201bbc0a86f010000000000000000}, _kCFStreamErrorCodeKey=-4, _kCFStreamErrorDomainKey=4}}, ), NSLocalizedDescription=The network connection was lost., NSErrorFailingURLStringKey=https://192.168.000.0/keepalive, NSErrorFailingURLKey=https://192.168.000.0/keepalive, _kCFStreamErrorDomainKey=4})) KeepAlive FAIL ignored count=2 error=Server error : Optional(Alamofire.AFError.sessionTaskFailed(error: Error Domain=NSURLErrorDomain Code=-1005 "The network connection was lost." UserInfo={_kCFStreamErrorCodeKey=-4, NSUnderlyingError=0x135e60f60 {Error Domain=kCFErrorDomainCFNetwork Code=-1005 "(null)" UserInfo={NSErrorPeerAddressKey=<CFData 0x144dfee40 [0x201746068]>{length = 16, capacity = 16, bytes = 0x100201bbc0a86f010000000000000000}, _kCFStreamErrorCodeKey=-4, _kCFStreamErrorDomainKey=4}}, Network type changed, hasWiFiInterface :false We are sending a keepalive request every 30 seconds to maintain the connection state with the device. Most of the issues occur during this keepalive process, and this is when the logs mentioned earlier are generated. Based on our debugging so far, the keepalive function itself is being called as expected. However, the execution appears to stall while waiting for a response from the device. After remaining in that state for some time, the session eventually ends with either a timeout or a connection loss error. We are use almofire 4.0.1. According to the firmware developer, when this issue occurs, there are no corresponding values or logs received on the device side. Therefore, we are currently investigating whether this might be related to a networking issue on the iPhone side. All other features are functioning normally. The problem occurs only when downloading VOD video files, and the reproduction rate is 100% under that condition.

Hi Team, Looking for an answer, if it's just us or a widespread issue. Since Sept, our clients Apple devices can't load a Captive Portal on Apple devices. Client wants the CNA to pop up and I can't get it to happen! Android and Windows devices all work correctly with their respective popups, but CNA will not work. No changes done on our side and after multiple tshoots and getting vendors to take multiple PCAPs found, Apple devices are not initiating a HTTP GET request as per Meraki >> https://documentation.meraki.com/MR/MR_Splash_Page/Splash_Page_Traffic_Flow_and_Troubleshooting The work around is to force a HTTP GET request by manually going into the browser and initiate a http site (we tried 1.1.1.1, also tried other public HTTP sites and it works) and that redirects to our Captive Portal page.

As part of iOS 26, we get X25519MLKEM768 key exchange group support, but SecP256r1MLKEM768 and SecP384r1MLKEM1024 are not supported. Is there any way to enable these key exchange groups on iOS 26? We need them for WKWebView and NSURLSession. STEPS TO REPRODUCE On iOS 26, connect to the PQC server using Safari. The key exchange group is limited to X25519MLKEM768.

I've implemented func urlSession(_ session: URLSession, task: URLSessionTask, willPerformHTTPRedirection response: HTTPURLResponse, newRequest request: URLRequest, completionHandler: @escaping (URLRequest?) -> Void) and func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) I've put a breakpoint in each but the BP in willPerformHTTPRedirection never fires. When the didWriteData fires and I inspect downloadTask.originalRequest I see my original request URL When I inspect downloadTask.currentRequest the returned request contains a different URL. I'm the farthest thing from an HTTP wizard, but I had thought when originalRequest differs from currentRequest there had been some sort of server-side 'redirection'. Is there a way for my code to receive a callback when something like this happens? NOTE: my download code works fine, I'm just hoping to detect the case when currentRequest changes. any/all guidance greatly appreciated on the off chance it helps, are are my original and current request values: (lldb) po downloadTask.originalRequest ▿ Optional<URLRequest> ▿ some : https://audio.listennotes.com/e/p/c524803c1a90412f922948274ecc3625/ (lldb) po downloadTask.currentRequest ▿ Optional<URLRequest> ▿ some : https://26973.mc.tritondigital.com:443/OMNY_HAPPIERWITHGRETCHENRUBIN_PODCAST_P/media-session/76cfceb2-1801-4570-b830-ded57611a9cf/d/clips/796469f9-ea34-46a2-8776-ad0f015d6beb/e1b22d0b-6974-4bb8-81ba-b2480119983c/2f35a8ca-b982-44e9-8122-b3dc000ae0e1/audio/direct/t1769587393/Ep_571_Want_to_Join_Us_for_a_No-Spend_February_Plus_a_Better_Word_for_Squats.mp3?t=1769587393&in_playlist=751ada7f-ded3-44b9-bfb8-b2480119985b&utm_source=Podcast

We are experiencing an issue with Safari in all versions from 18.0 to 18.5 that does not occur in version 17. It affects both iPhones and Macs. And does not happen in Chrome or Windows. The problem is impacting our customers, and our monitoring tools show a dramatic increase in error volume as more users buy/upgrade to iOS 18. The issue relates to network connectivity that is lost randomly. I can reliably reproduce the issue online in production, as well as on my local development environment. For example our website backoffice has a ping, that has a frequency of X seconds, or when user is doing actions like add to a cart increasing the quantity that requires backend validation with some specific frequency the issue is noticable... To test this I ran a JS code to simulate a ping with a timer that calls a local-dev API (a probe that waits 2s to simulate "work") and delay the next HTTP requests with a dynamic value to simulate network conditions: Note: To even make the issue more clear, I'm using GET with application/json payload to make the request not simple, and require a Pre-flight request, which doubles the issue. (async () =&amp;gt; { for (let i = 0; i &amp;lt; 30; i++) { try { console.log(`Request start ${i} ${new Date().toLocaleString()}`); const res = await fetch(`https://api.redated.com:8090/1/*****/probe?`, { method: 'GET', mode: "cors", //headers: {'Content-Type': 'text/plain'}, headers: { 'Content-Type': 'application/json' }, }); console.log(`Request end ${i} ${new Date().toLocaleString()} status:`, res.status); } catch (err) { console.error(`Request ${i} ${new Date().toLocaleString()} error:`, err); } let delta = Math.floor(Math.random() * 10); console.log("wait delta",delta); await new Promise(r =&amp;gt; setTimeout(r, 1000 - delta)); } })(); For simplicity lets see a case where it fails 1 time only out of 10 requests. (Adjusting the "delta" var on the time interval create more or less errors...) This are the results: The network connection was lost error, which is false, since this is on my localhost machine, but this happens many times and is very reproducible in local and production online. The dev-tools and network tab shows empty for status error, ip, connection_id etc.. its like the request is being terminated very soon. Later I did a detailed debugging with safari and wireshark to really nail down the network flow of the problem: I will explain what this means: Frame 10824 – 18:52:03.939197: new connection initiated (SYN, ACK, ECE). Frame 10831 – 18:52:04.061531: Client sends payload (preflight request) to the server. Frame 10959 – 18:52:09.207686: Server responds with data to (preflight response) to the client. Frame 10960 – 18:52:09.207856: Client acknowledges (ACK) receipt of the preflight response. Frame 10961 – 18:52:09.212188: Client sends the actual request payload after preflight OK and then server replies with ACK. Frame 11092 – 18:52:14.332951: Server sends the final payload (main request response) to the client. Frame 11093 – 18:52:14.333093: captures the client acknowledging the final server response, which marks the successful completion of the main request. Frame 11146 – 18:52:15.348433: [IMPORTANT] the client attempts to send another new request just one second later, which is extremely close to the keep-alive timeout of 1 second. The last message from the server was at 18:52:14.332951, meaning the connection’s keep-alive timeout is predicted to end around 18:52:15.332951 but it does not. The new request is sent at 18:52:15.348433, just microseconds after the predicted timeout. The request leaves before the client browser knows the connection is closed, but by the time it arrives at the server, the connection is already dead. Frame 11147 – 18:52:15.356910: Shows the server finally sending the FIN,ACK to indicate the connection is closed. This happens slightly later than the predicted time, at microsecond 356910 compared to the expected 332951. The FIN,ACK corresponds to sequence 1193 from the ACK of the last data packet in frame 11093. Conclusions: The root cause is related to network handling issues, when the server runs in a setting of keep-alive behavior and keep-alive timeout (in this case 1s) and network timming issue with Safari reusing a closed connection without retrying. In this situation the browser should retry the request, which is what other browsers do and what Safari did before version 18, since it did not suffer from this issue. This behaviour must differ from previous Safari versions (however i read all the public change logs and could not related the regression change). Also is more pronounced with HTTP/1.1 connections due to how the keep-alive is handled. When the server is configured with a short keep-alive timeout of 1 second, and requests are sent at roughly one-second intervals, such as API pings at fixed intervals or user actions like incrementing a cart quantity that trigger backend calls where the probability of failure is high. This effect is even more apparent when the request uses a preflight with POST because it doubles the chance, although GET requests are also affected. This was a just a test case, but in real production our monitoring tools started to detect a big increment with this network error at scale, many requests per day... which is very disrupting, because user actions are randomly being dropped when the user actions and timming happens to be just near a previous connection, where keep alive timeout kicks-in, but because the browser is not yet notified it re-uses the same connection, but by the time it arrived the server is a dead connection. The safari just does nothing about it, does not even retry, be it a pre-flight or not, it just gives this error. Other browsers don't have this issue. Thanks!

I have an app that has been using the following code to down load audio files: if let url = URL(string: episode.fetchPath()) { var request = URLRequest(url: url) request.httpMethod = "get" let task = session.downloadTask(with: request) And then the following completionHandler code: func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) { try FileManager.default.moveItem(at: location, to: localUrl) In the spirit of modernization, I'm trying to update this code to use async await: var request = URLRequest(url: url) request.httpMethod = "get" let (data, response) = try await URLSession.shared.data(for: request) try data.write(to: localUrl, options: [.atomicWrite, .completeFileProtection]) Both these code paths use the same url value. Both return the same Data blobs (they return the same hash value) Unfortunately the second code path (using await) introduces a problem. When the audio is playing and the iPhone goes to sleep, after 15 seconds, the audio stops. This problem does not occur when running the first code (using the didFinish completion handler) Same data, stored in the same URL, but using different URLSession calls. I would like to use async/await and not have to experience the audio ending after just 15 seconds of the device screen being asleep. any guidance greatly appreciated.

When setting new entitlements com.apple.developer.networking.carrier-constrained.appcategory and com.apple.developer.networking.carrier-constrained.app-optimized, I have a question about how URLSession should behave. I notice we have a way to specify whether a Network connection should allow ultra-constrained paths via NWParameters allowUltraConstrainedPaths: https://developer.apple.com/documentation/network/nwparameters/allowultraconstrainedpaths There does not appear to be a similar property on URLSessionConfiguration. In an ultra-constrained (eg. satellite) network, should we expect all requests made through an URLSession to fail? Does all network activity when ultra-constrained need to go through a NWConnection or NetworkConnection specifically configured with allowUltraConstrainedPaths, or can URLSession ever be configured to allow ultra-constrained paths?

There are multiple report of crashes on URLConnectionLoader::loadWithWhatToDo. The crashed thread in the stack traces pointing to calls inside CFNetwork which seems to be internal library in iOS. The crash has happened quite a while already (but we cannot detect when the crash started to occur) and impacted multiple iOS versions recorded from iOS 15.4 to 18.4.1 that was recorded in Xcode crash report organizer so far. Unfortunately, we have no idea on how to reproduce it yet but the crash keeps on increasing and affect more on iOS 18 users (which makes sense because many people updated their iOS to the newer version) and we haven’t found any clue on what actually happened and how to fix it on the crash reports. What we understand is it seems to come from a network request that happened to trigger the crash but we need more information on what (condition) actually cause it and how to solve it. Hereby, I attach sample crash report for both iOS 15 and 18. I also have submitted a report (that include more crash reports) with number: FB17775979. Will appreciate any insight regarding this issue and any resolution that we can do to avoid it. iOS 15.crash iOS 18.crash

Is there any way to forcibly disable using QUIC? I've noticed this ends up causing issues with our ISP / router, and noticed for many of our customers as well. Creating an ephemeral session doesn't change things, and setting the request to "assumeHttp3Capable" to false doesn't fix things either. We are using Cloudflare Workers as the URL we are hitting, and thus aren't able to disable this server-side.

I have an Xcode app where currently txt files in the project display text data as a list. I can search through the lists and have buttons that will swap between different lists of information that you can look through. The next task is I have URL connections to docx files on a SharePoint site. I am trying to use an URLsession function to connect to the URL links to download the documents to the document directory then have the application read the doc information to then be displayed as the txt info would. The idea is that the docx files are a type of online update version of the data. So when the app is used and on wifi, the app can update the list data with the docx files. I have code set up that should access the URL files but I am struggling to figure out how to read the data and access from this Documents directory. I have been looking online and so far I am at a loss on where to go here. If anyone can help or provide some insight I would greatly appreciate it. I can try and provide code samples to help explain things if that is needed.