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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.

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“Wi-Fi Aware Sample” on Phone quit unexpectedly.
The app “Wi-Fi Aware Sample” on Bojie的iPhone quit unexpectedly. Domain: IDEDebugSessionErrorDomain Code: 20 Failure Reason: Message from debugger: The LLDB RPC server has crashed. You may need to manually terminate your process. The crash log is located in ~/Library/Logs/DiagnosticReports and has a prefix 'lldb-rpc-server'. Please file a bug and attach the most recent crash log. User Info: { DVTErrorCreationDateKey = "2025-09-17 10:26:56 +0000"; IDEDebugSessionErrorUserInfoUnavailabilityError = "Error Domain=com.apple.dt.deviceprep Code=-10 "Fetching debug symbols for Bojie\U7684iPhone" UserInfo={NSLocalizedRecoverySuggestion=Xcode will continue when the operation completes., NSLocalizedDescription=Fetching debug symbols for Bojie\U7684iPhone}"; IDERunOperationFailingWorker = DBGLLDBLauncher; } Event Metadata: com.apple.dt.IDERunOperationWorkerFinished : { "device_identifier" = "00008101-001E29E01E63003A"; "device_isCoreDevice" = 1; "device_model" = "iPhone13,3"; "device_osBuild" = "26.0 (23A341)"; "device_osBuild_monotonic" = 2300034100; "device_os_variant" = 1; "device_platform" = "com.apple.platform.iphoneos"; "device_platform_family" = 2; "device_reality" = 1; "device_thinningType" = "iPhone13,3"; "device_transport" = 1; "dvt_coredevice_version" = "477.23"; "dvt_coredevice_version_monotonic" = 477023000000000; "dvt_coresimulator_version" = 1043; "dvt_coresimulator_version_monotonic" = 1043000000000000; "dvt_mobiledevice_version" = "1818.0.1"; "dvt_mobiledevice_version_monotonic" = 1818000001000000; "launchSession_schemeCommand" = Run; "launchSession_schemeCommand_enum" = 1; "launchSession_targetArch" = arm64; "launchSession_targetArch_enum" = 6; "operation_duration_ms" = 1922640; "operation_errorCode" = 20; "operation_errorDomain" = IDEDebugSessionErrorDomain; "operation_errorWorker" = DBGLLDBLauncher; "operation_error_reportable" = 1; "operation_name" = IDERunOperationWorkerGroup; "operation_unavailabilityErrorCode" = "-10"; "operation_unavailabilityErrorDomain" = "com.apple.dt.deviceprep"; "param_consoleMode" = 1; "param_debugger_attachToExtensions" = 0; "param_debugger_attachToXPC" = 1; "param_debugger_type" = 3; "param_destination_isProxy" = 0; "param_destination_platform" = "com.apple.platform.iphoneos"; "param_diag_MainThreadChecker_stopOnIssue" = 0; "param_diag_MallocStackLogging_enableDuringAttach" = 0; "param_diag_MallocStackLogging_enableForXPC" = 1; "param_diag_allowLocationSimulation" = 1; "param_diag_checker_mtc_enable" = 1; "param_diag_checker_tpc_enable" = 1; "param_diag_gpu_frameCapture_enable" = 0; "param_diag_gpu_shaderValidation_enable" = 0; "param_diag_gpu_validation_enable" = 0; "param_diag_guardMalloc_enable" = 0; "param_diag_memoryGraphOnResourceException" = 0; "param_diag_queueDebugging_enable" = 1; "param_diag_runtimeProfile_generate" = 0; "param_diag_sanitizer_asan_enable" = 0; "param_diag_sanitizer_tsan_enable" = 0; "param_diag_sanitizer_tsan_stopOnIssue" = 0; "param_diag_sanitizer_ubsan_enable" = 0; "param_diag_sanitizer_ubsan_stopOnIssue" = 0; "param_diag_showNonLocalizedStrings" = 0; "param_diag_viewDebugging_enabled" = 1; "param_diag_viewDebugging_insertDylibOnLaunch" = 1; "param_install_style" = 2; "param_launcher_UID" = 2; "param_launcher_allowDeviceSensorReplayData" = 0; "param_launcher_kind" = 0; "param_launcher_style" = 99; "param_launcher_substyle" = 0; "param_lldbVersion_component_idx_1" = 0; "param_lldbVersion_monotonic" = 170300230950; "param_runnable_appExtensionHostRunMode" = 0; "param_runnable_productType" = "com.apple.product-type.application"; "param_testing_launchedForTesting" = 0; "param_testing_suppressSimulatorApp" = 0; "param_testing_usingCLI" = 0; "sdk_canonicalName" = "iphoneos26.0"; "sdk_osVersion" = "26.0"; "sdk_platformID" = 2; "sdk_variant" = iphoneos; "sdk_version_monotonic" = 2300527605; } System Information macOS Version 15.5 (Build 24F74) Xcode 26.0 (24141.31) (Build 17A5241o) Timestamp: 2025-09-17T18:26:56+08:00
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207
Sep ’25
Unable to Find Local Network Devices in Simulator – Permission Issue on M4 Mac, macOS 15.5, Xcode 16.1
Hello, I'm running into an issue while developing an iOS app that requires local network access. I’m using the latest MacBook Air M4 with macOS sequoia 15.5 and Xcode 16.1. In the iOS Simulator, my app fails to discover devices connected to the same local network. I’ve already added the necessary key to the Info.plist: NSLocalNetworkUsageDescription This app needs access to local network devices. When I run the app on a real device and M2 Chip Macbook's simulators, it works fine for local network permission as expected. However, in the M4 Chip Macbook's Simulator: The app can’t find any devices on the local network Bonjour/mDNS seems not to be working as well I’ve tried the following without success: Restarting Simulator and Mac Resetting network settings in Simulator Confirming app permissions under System Settings > Privacy & Security Has anyone else encountered this issue with the new Xcode/macOS combo? Is local network access just broken in the Simulator for now, or is there a workaround? Thanks in advance!
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202
May ’25
Disable QUIC/HTTP3 support for specific MacOS application
Hello, I am currently investigating if we can disable usage of QUIC on application level. I know we can set enable_quic from /Library/Preferences/com.apple.networkd.plist to false but it will have a global impact since this is a system file, all the applications on machine will stop using QUIC. I don't want that. What i am looking for is to disable QUIC only for my application. Is there any way i can modify URLSession object in my application and disable QUIC? or modify URLSessionConfiguration so system will not use QUIC?
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225
Aug ’25
Extra-ordinary Networking
Most apps perform ordinary network operations, like fetching an HTTP resource with URLSession and opening a TCP connection to a mail server with Network framework. These operations are not without their challenges, but they’re the well-trodden path. If your app performs ordinary networking, see TN3151 Choosing the right networking API for recommendations as to where to start. Some apps have extra-ordinary networking requirements. For example, apps that: Help the user configure a Wi-Fi accessory Require a connection to run over a specific interface Listen for incoming connections Building such an app is tricky because: Networking is hard in general. Apple devices support very dynamic networking, and your app has to work well in whatever environment it’s running in. Documentation for the APIs you need is tucked away in man pages and doc comments. In many cases you have to assemble these APIs in creative ways. If you’re developing an app with extra-ordinary networking requirements, this post is for you. Note If you have questions or comments about any of the topics discussed here, put them in a new thread here on DevForums. Make sure I see it by putting it in the App & System Services > Networking area. And feel free to add tags appropriate to the specific technology you’re using, like Foundation, CFNetwork, Network, or Network Extension. Links, Links, and More Links Each topic is covered in a separate post: The iOS Wi-Fi Lifecycle describes how iOS joins and leaves Wi-Fi networks. Understanding this is especially important if you’re building an app that works with a Wi-Fi accessory. Network Interface Concepts explains how Apple platforms manage network interfaces. If you’ve got this far, you definitely want to read this. Network Interface Techniques offers a high-level overview of some of the more common techniques you need when working with network interfaces. Network Interface APIs describes APIs and core techniques for working with network interfaces. It’s referenced by many other posts. Running an HTTP Request over WWAN explains why most apps should not force an HTTP request to run over WWAN, what they should do instead, and what to do if you really need that behaviour. If you’re building an iOS app with an embedded network server, see Showing Connection Information in an iOS Server for details on how to get the information to show to your user so they can connect to your server. Many folks run into trouble when they try to find the device’s IP address, or other seemingly simple things, like the name of the Wi-Fi interface. Don’t Try to Get the Device’s IP Address explains why these problems are hard, and offers alternative approaches that function correctly in all network environments. Similarly, folks also run into trouble when trying to get the host name. On Host Names explains why that’s more complex than you might think. If you’re working with broadcasts or multicasts, see Broadcasts and Multicasts, Hints and Tips. If you’re building an app that works with a Wi-Fi accessory, see Working with a Wi-Fi Accessory. If you’re trying to gather network interface statistics, see Network Interface Statistics. There are also some posts that are not part of this series but likely to be of interest if you’re working in this space: TN3179 Understanding local network privacy discusses the local network privacy feature. Calling BSD Sockets from Swift does what it says on the tin, that is, explains how to call BSD Sockets from Swift. When doing weird things with the network, you often find yourself having to use BSD Sockets, and that API is not easy to call from Swift. The code therein is primarily for the benefit of test projects, oh, and DevForums posts like these. TN3111 iOS Wi-Fi API overview is a critical resource if you’re doing Wi-Fi specific stuff on iOS. TLS For Accessory Developers tackles the tricky topic of how to communicate securely with a network-based accessory. A Peek Behind the NECP Curtain discusses NECP, a subsystem that control which programs have access to which network interfaces. Networking Resources has links to many other useful resources. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" Revision History 2025-07-31 Added a link to A Peek Behind the NECP Curtain. 2025-03-28 Added a link to On Host Names. 2025-01-16 Added a link to Broadcasts and Multicasts, Hints and Tips. Updated the local network privacy link to point to TN3179. Made other minor editorial changes. 2024-04-30 Added a link to Network Interface Statistics. 2023-09-14 Added a link to TLS For Accessory Developers. 2023-07-23 First posted.
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5.7k
Jul ’25
Securely transmit UIImage to app running on desktop website
Hello everyone, I'm trying to figure out how to transmit a UIImage (png or tiff) securely to an application running in my desktop browser (Mac or PC). The desktop application and iOS app would potentially be running on the same local network (iOS hotspot or something) or have no internet connection at all. I'm trying to securely send over an image that the running desktop app could ingest. I was thinking something like a local server securely accepting image data from an iPhone. Any suggestions ideas or where to look for more info would be greatly appreciated! Thank you for your help.
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124
May ’25
URLSession.dataTask(with: URL) error: Type of expression is ambiguous without a type annotation
I'm a long-time developer, but pretty new to Swift. I'm trying to get information from a web service (and found code online that I adjusted to build the function below). (Note: AAA_Result -- referenced towards the end -- is another class in my project) Trouble is, I'm getting the subject error on the call to session.dataTask. Any help/suggestions/doc pointers will be greatly appreciated!!! var result: Bool = false var cancellable: AnyCancellable? self.name = name let params = "json={\"\"}}" // removed json details let base_url = URL(string: "https://aaa.yyy.com?params=\(params)&format=json")! // removed URL specifics do { let task = URLSession.shared.dataTask(with: base_url) { data, response, error in if let error = error { print("Error: \(error)") } guard let response = response as? HTTPURLResponse, (200...299).contains(response.statusCode) else { print("Error \(String(describing: response))") } do { let decoder = JSONDecoder() let ar = try decoder.decode(AAA_Result.self, from: response.value) // removed specific details... result = true } catch { print(error) } } task.resume() } catch { print(error) } return result }
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116
May ’25
On Host Names
For important background information, read Extra-ordinary Networking before reading this. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" On Host Names I commonly see questions like How do I get the device’s host name? This question doesn’t make sense without more context. Apple systems have a variety of things that you might consider to be the host name: The user-assigned device name — This is a user-visible value, for example, Guy Smiley. People set this in Settings > General > About > Name. The local host name — This is a DNS name used by Bonjour, for example, guy-smiley.local. By default this is algorithmically derived from the user-assigned device name. On macOS, people can override this in Settings > General > Sharing > Local hostname. The reverse DNS name associated with the various IP addresses assigned to the device’s various network interfaces That last one is pretty much useless. You can’t get a single host name because there isn’t a single IP address. For more on that, see Don’t Try to Get the Device’s IP Address. The other two have well-defined answers, although those answers vary by platform. I’ll talk more about that below. Before getting to that, however, let’s look at the big picture. Big Picture The use cases for the user-assigned device name are pretty clear. I rarely see folks confused about that. Another use case for this stuff is that you’ve started a server and you want to tell the user how to connect to it. I discuss this in detail in Showing Connection Information in an iOS Server. However, most folks who run into problems like this do so because they’re suffering from one of the following misconceptions: The device has a DNS name. Its DNS name is unique. Its DNS name doesn’t change. Its DNS name is in some way useful for networking. Some of these may be true in some specific circumstances, but none of them are true in all circumstances. These issues are not unique to Apple platforms — if you look at the Posix spec for gethostname, it says nothing about DNS! — but folks tend to notice these problems more on Apple platforms because Apple devices are often deployed to highly dynamic network environments. So, before you start using the APIs discussed in this post, think carefully about your assumptions. And if you actually do want to work with DNS, there are two cases to consider: If you’re looking for the local host name, use the APIs discussed above. In other cases, it’s likely that the APIs in this post will not be helpful and you’d be better off focusing on DNS APIs [1]. [1] The API I recommend for this is DNS-SD. See the DNS section in TN3151 Choosing the right networking API. macOS To get the user-assigned device name, call the SCDynamicStoreCopyComputerName(_:_:) function. For example: let userAssignedDeviceName = SCDynamicStoreCopyComputerName(nil, nil) as String? To get the local host name, call the SCDynamicStoreCopyLocalHostName(_:) function. For example: let localHostName = SCDynamicStoreCopyLocalHostName(nil) as String? IMPORTANT This returns just the name label. To form a local host name, append .local.. Both routines return an optional result; code defensively! If you’re displaying these values to the user, use the System Configuration framework dynamic store notification mechanism to keep your UI up to date. iOS and Friends On iOS, iPadOS, tvOS, and visionOS, get the user-assigned device name from the name property on UIDevice. IMPORTANT Access to this is now restricted. For more on that, see the documentation for the com.apple.developer.device-information.user-assigned-device-name entitlement. There is no direct mechanism to get the local host name. Other APIs There are a wide variety of other APIs that purport to return the host name. These include: gethostname The name property on NSHost [1] The hostName property on NSProcessInfo (ProcessInfo in Swift) These are problematic for a number of reasons: They have a complex implementation that makes it hard to predict what value you’ll get back. They might end up trying to infer the host name from the network environment. The existing behaviour is hard to change due to compatibility concerns. Some of them are marked as to-be-deprecated. IMPORTANT The second issue is particularly problematic, because it involves synchronous DNS requests [2]. That’s slow in general. Worse yet, if the network environment is restricted in some way, these calls can be very slow, taking about 30 seconds to time out. Given these problems, it’s generally best to avoid calling these routines at all. [1] It also has a names property, which is a little closer to reality but still not particularly useful. [2] Actually, that’s not true for gethostname. Rather, that call just returns whatever was last set by sethostname. This is always fast. The System Configuration framework infrastructure calls sethostname to update the host name as the system state changes.
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236
Mar ’25
iPhone App 进行网络请求的时候出错,报错信息为:未能完成该操作。设备上无剩余空间
1、已经检查过手机的存储空间,还有一百多G的空间。app端进行网络接口情况的时候报错了,报错信息如下: Error : Error Domain=NSPOSIXErrorDomain Code=28 "No space left on device" UserInfo={_NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <7DB1CBFD-B9BE-422D-9C9A-78D8FC04DC1B>.<76>, _kCFStreamErrorDomainKey=1, _kCFStreamErrorCodeKey=28, _NSURLErrorRelatedURLSessionTaskErrorKey=( "LocalDataTask <7DB1CBFD-B9BE-422D-9C9A-78D8FC04DC1B>.<76>" ), _NSURLErrorNWPathKey=satisfied (Path is satisfied), interface: pdp_ip0[lte], ipv4, ipv6, dns, expensive, estimated upload: 65536Bps, uses cell} 2、手机型号是iPhone 15 Plus,iOS 17.6.1
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387
Jun ’25
Crash on "Dispatch queue: NEFlow queue" when __88-[NEExtensionAppProxyProviderContext setInitialFlowDivertControlSocket:extraValidation:]_block_invoke.90
I observed the following crash: Code Type: ARM-64 (Native) Parent Process: launchd [1] User ID: 0 Date/Time: 2025-10-07 13:48:29.082 OS Version: macOS 15.6 (24G84) Report Version: 12 Anonymous UUID: 8B651788-4B2E-7869-516B-1DA0D60F3744 Crashed Thread: 3 Dispatch queue: NEFlow queue Exception Type: EXC_BAD_ACCESS (SIGSEGV) Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000054 ... Thread 3 Crashed: Dispatch queue: NEFlow queue 0 libdispatch.dylib 0x000000019af6da34 dispatch_async + 192 1 libnetworkextension.dylib 0x00000001b0cf8580 __flow_startup_block_invoke.216 + 124 2 com.apple.NetworkExtension 0x00000001adf97da8 __88-[NEExtensionAppProxyProviderContext setInitialFlowDivertControlSocket:extraValidation:]_block_invoke.90 + 860 3 libnetworkextension.dylib 0x00000001b0cf8140 __flow_startup_block_invoke.214 + 172 4 libdispatch.dylib 0x000000019af67b2c _dispatch_call_block_and_release + 32 5 libdispatch.dylib 0x000000019af8185c _dispatch_client_callout + 16 6 libdispatch.dylib 0x000000019af70350 _dispatch_lane_serial_drain + 740 7 libdispatch.dylib 0x000000019af70e2c _dispatch_lane_invoke + 388 8 libdispatch.dylib 0x000000019af7b264 _dispatch_root_queue_drain_deferred_wlh + 292 9 libdispatch.dylib 0x000000019af7aae8 _dispatch_workloop_worker_thread + 540 10 libsystem_pthread.dylib 0x000000019b11be64 _pthread_wqthread + 292 11 libsystem_pthread.dylib 0x000000019b11ab74 start_wqthread + 8 ... It appears that the crash is caused by the flow director queue becoming NULL when dispatch_async is called (accessing address 0x0000000000000054). Meanwhile, my transparent proxy was still running. I'm wondering if this is a known issue or if anyone else has encountered the same problem. @eskimo
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504
Oct ’25
How to test application using Thread networking on MacOS?
I would like to test running some Thread Networking code on my MacOS machine: import ThreadNetwork let client = THClient() let bIsPreferredAvailable = await client.isPreferredAvailable() but I get some errors when trying to create an instance of the THClient class: Client: -[THClient connectToXPCService]_block_invoke - CTCS XPC Client is interrupted. Client: -[THClient getConnectionEntitlementValidity]_block_invoke - clientProxyWithErrorHandler Error: Error Domain=NSCocoaErrorDomain Code=4097 "connection to service named com.apple.ThreadNetwork.xpc" UserInfo={NSDebugDescription=connection to service named com.apple.ThreadNetwork.xpc} Client: -[THClient init] - XPC Client Init Failed Invalidating XPC connection. Client: -[THClient getConnectionEntitlementValidity]_block_invoke - clientProxyWithErrorHandler Error: Error Domain=NSCocoaErrorDomain Code=4097 "connection to service named com.apple.ThreadNetwork.xpc" UserInfo={NSDebugDescription=connection to service named com.apple.ThreadNetwork.xpc} How can I get the code to run?
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266
Mar ’25
Understanding Also-Ran Connections
Every now and again folks notice that Network framework seems to create an unexpected number of connections on the wire. This post explains why that happens and what you should do about it. If you have questions or comments, put them in a new thread here on the forums. Use the App & System Services > Networking topic area and the Network tag. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" Understanding Also-Ran Connections Network framework implements the Happy Eyeballs algorithm. That might create more on-the-wire connections than you expect. There are two common places where folks notice this: When looking at a packet trace When implementing a listener Imagine that you’ve implemented a TCP server using NWListener and you connect to it from a client using NWConnection. In many situations there are multiple network paths between the client and the server. For example, on a local network there’s always at least two paths: the link-local IPv6 path and either an infrastructure IPv4 path or the link-local IPv4 path. When you start your NWConnection, Network framework’s Happy Eyeballs algorithm might [1] start a TCP connection for each of these paths. It then races those connections. The one that connects first is the ‘winner’, and Network framework uses that connection for your traffic. Once it has a winner, the other connections, the also-ran connections, are redundant, and Network framework just closes them. You can observe this behaviour on the client side by looking in the system log. Many Network framework log entries (subsystem com.apple.network) contain a connection identifier. For example C8 is the eighth connection started by this process. Each connection may have child connections (C8.1, C8.2, …) and grandchild connections (C8.1.1, C8.1.2, …), and so on. You’ll see state transitions for these child connections occurring in parallel. For example, the following log entries show that C8 is racing the connection of two grandchild connections, C8.1.1 and C8.1.2: type: debug time: 12:22:26.825331+0100 process: TestAlsoRanConnections subsystem: com.apple.network category: connection message: nw_socket_connect [C8.1.1:1] Calling connectx(…) type: debug time: 12:22:26.964150+0100 process: TestAlsoRanConnections subsystem: com.apple.network category: connection message: nw_socket_connect [C8.1.2:1] Calling connectx(…) Note For more information about accessing the system log, see Your Friend the System Log. You also see this on the server side, but in this case each connection is visible to your code. When you connect from the client, Network framework calls your listener’s new connection handler with multiple connections. One of those is the winning connection and you’ll receive traffic on it. The others are the also-ran connections, and they close promptly. IMPORTANT Depending on network conditions there may be no also-ran connections. Or there may be lots of them. If you want to test the also-ran connection case, use Network Link Conditioner to add a bunch of delay to your packets. You don’t need to write special code to handle also-ran connections. From the perspective of your listener, these are simply connections that open and then immediately close. There’s no difference between an also-ran connection and, say, a connection from a client that immediately crashes. Or a connection generated by someone doing a port scan. Your server must be resilient to such things. However, the presence of these also-ran connections can be confusing, especially if you’re just getting started with Network framework, and hence this post. [1] This is “might” because the exact behaviour depends on network conditions. More on that below.
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156
Apr ’25
After the device wake ups, NEFilterDataProvider causes internet access issue intermittently
We have a NEFilterDataProvider extension that intercepts all TCP and UDP IPv4/6 traffic. At times just after wakeup from sleep, it causes internet access issues, such as showing "This site can't be reached" when opening websites. The traffic is not being dropped by the extension. According to the logs, the connection is being closed after approximately 4 minutes. During the issue, the flow logs are as follows: Flow 515129771 is connecting New flow: NEFlow type = stream, app = com.google.Chrome.helper... Detaching, ref count = 2 (logged after ~4 minutes) Sending close, how = 2 Removing from group 2, ref count = 2 Destroying, app tx 0, tunnel tx 0, tunnel rx 0 Closing reads, not closed by plugin Closing writes, not sending close Any suggestions on the possible cause and how to further debug it?
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240
Mar ’25
Recommended alternatives to leaf cert pinning to prevent MITM
Hey there Are there any recommendations or guidance for apps on alternatives to certificate pinning to secure their device network traffic? I want to move away from the overhead and risk associated with rotating certificates when using leaf pinning. However, I also don't want people to be able to perform a MITM attack easily using something like Charles Proxy with a self‑signed certificate added to the trust store. My understanding is that an app cannot distinguish between user‑trusted certificates and system‑trusted certificates in the trust store, so it cannot block traffic that uses user‑trusted certificates.
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54
Jan ’26
VPN Stuck at connecting
Hello, I’ve run into some strange behavior with the macOS System Extension using a Packet Tunnel. The issue showed up after the device went to sleep while the VPN was running. When I woke the computer, the VPN tried to reconnect but never succeeded — it just stayed stuck in the “connecting” state. I was able to turn the VPN off, but every attempt to turn it back on failed and got stuck at “connecting” again. Even removing the VPN configuration from Settings didn’t help. The only thing that worked was disabling the system extension completely. While checking the logs, I noticed thousands of identical log messages appearing within just a few seconds: nesessionmanager(562) deny(1) system-fsctl (_IO "h" 47) 17:11:52.481498+0200 NESMVPNSession[Primary Tunnel:Secure DNS: got On Demand start message from pid 5454 com.apple.networkextension 17:11:52.481568+0200 NESMVPNSession[Primary Tunnel:Secure DNS: got On Demand start message from pid 5454 com.apple.networkextension 17:11:52.481580+0200 NESMVPNSession[Primary Tunnel:Secure DNS: got On Demand start message from pid 5454 com.apple.networkextension 17:11:52.481587+0200 NESMVPNSession[Primary Tunnel:Secure DNS: got On Demand start message from pid 5454 com.apple.networkextension 17:11:52.481646+0200 NESMVPNSession[Primary Tunnel:Secure DNS: got On Demand start message from pid 5446 com.apple.networkextension 17:11:52.481664+0200 NESMVPNSession[Primary Tunnel:Secure DNS: got On Demand start message from pid 5446 com.apple.networkextension 17:11:52.481671+0200 NESMVPNSession[Primary Tunnel:Secure DNS: got On Demand start message from pid 5446 com.apple.networkextension 17:11:52.481676+0200 NESMVPNSession[Primary Tunnel:Secure DNS: got On Demand start message from pid 5446 com.apple.networkextension 17:11:52.481682+0200 NESMVPNSession[Primary Tunnel:Secure DNS: got On Demand start message from pid 5446 com.apple.networkextension 17:11:52.481687+0200 NESMVPNSession[Primary Tunnel:Secure DNS: got On Demand start message from pid 5446 com.apple.networkextension After the burst of these repeated messages, I started seeing logs like the following: 17:11:52.481759+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Received a start command from Spotify Helper[69038] com.apple.networkextension 17:11:52.481790+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Skip a start command from Spotify Helper[69038]: session in state connecting com.apple.networkextension 17:11:52.481949+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Received a start command from Spotify Helper[69038] com.apple.networkextension 17:11:52.481966+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Skip a start command from Spotify Helper[69038]: session in state connecting com.apple.networkextension 17:11:52.481986+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Received a start command from Spotify Helper[69038] com.apple.networkextension 17:11:52.481992+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Skip a start command from Spotify Helper[69038]: session in state connecting com.apple.networkextension 17:11:52.482003+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Received a start command from Spotify Helper[69038] com.apple.networkextension 17:11:52.482011+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Skip a start command from Spotify Helper[69038]: session in state connecting com.apple.networkextension 17:11:52.482022+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Received a start command from Spotify Helper[69038] com.apple.networkextension 17:11:52.482028+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Skip a start command from Spotify Helper[69038]: session in state connecting com.apple.networkextension 17:11:52.482039+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Received a start command from Spotify Helper[69038] com.apple.networkextension 17:11:52.482049+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Skip a start command from Spotify Helper[69038]: session in state connecting com.apple.networkextension 17:11:52.482060+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Received a start command from Slack Helper[84828] com.apple.networkextension 17:11:52.482069+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Skip a start command from Slack Helper[84828]: session in state connecting com.apple.networkextension 17:11:52.482079+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Received a start command from sharingd[764] com.apple.networkextension 17:11:52.482086+0200 NESMVPNSession[Primary Tunnel:Secure DNS: Skip a start command from sharingd[764]: session in state connecting com.apple.networkextension It is clear that the connection is in a loop of submitting request to start and then failing. This problem occured only after sleep on macOS 26.0 and 15.6. This issue only occured after the system woke up from sleep. macOS 15.6 and 26.0. Is this a known problem, and how should I go about troubleshooting or resolving it?
3
0
165
Oct ’25
Recording a Packet Trace
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?
5
0
88
17h
iOS 26 Crash: _xzm_xzone_malloc_freelist_outlined in com.apple.network.connections
Hello Apple Support Team, We are seeing a production crash on iOS 26 devices that appears to originate from Apple system frameworks rather than application code. Crash Summary Crash signature: _xzm_xzone_malloc_freelist_outlined Crashed thread: com.apple.network.connections Frameworks involved: CFNetwork, Security, libdispatch, libsystem_malloc Affected OS: iOS 26.x App built with: Xcode 16 Devices: Multiple models (not device-specific) Reproducibility: Intermittent, higher frequency during app launch / background networking Observed Stack Trace (top frames) _xzm_xzone_malloc_freelist_outlined dispatch_data_create_alloc xpc_data_deserialize SecTrustEvaluateIfNecessary CFNetwork HTTPProtocol / HTTP3Connection com.apple.network.connections App Context The app uses URLSession for networking. Multiple third-party SDKs are integrated (Firebase Analytics, Dynatrace, Appsflyer, and similar analytics/monitoring SDKs). These SDKs perform concurrent background network requests, especially during app launch and foreground transitions. No unsafe memory operations (manual malloc/free, unsafe pointers, or custom networking stacks) are used in the app code. Key Observations The crash is predominantly observed on iOS 26 and not on earlier iOS versions. Stack traces do not include application symbols. Disabling or delaying analytics SDK initialization significantly reduces the crash rate. Reducing concurrent network requests and limiting HTTP/3 usage also mitigates the issue. This suggests a potential regression in CFNetwork / Network.framework / HTTP/3 handling combined with the new memory allocator (xzone) on iOS 26. Impact Random app termination during background networking. Occurs without a clear deterministic repro path, making it difficult to fully mitigate at the app level. Request Could you please help investigate whether this is a known iOS 26 issue related to: HTTP/3 / QUIC networking XPC deserialization Memory allocation in the new xzone allocator High-concurrency network requests We would appreciate guidance on: Recommended mitigations Whether this issue is already tracked internally Any best practices for apps integrating multiple analytics SDKs on iOS 26 Crash logs and additional diagnostics can be provided if needed. Thank you for your support. Best regards, Dhananjay
0
0
126
Feb ’26
Bonjour Connectivity Optimization
Hi folks, I'm building an iOS companion app to a local hosted server app (hosted on 0.0.0.0). The MacOS app locally connects to this server hosted, and I took the approach of advertising the server using a Daemon and BonjourwithTXT(for port) and then net service to resolve a local name. Unfortunately if there's not enough time given after the iPhone/iPad is plugged in (usb or ethernet), the app will cycle through attempts and disconnects many times before connecting and I'm trying to find a way to only connect when a viable en interface is available. I've run into a weird thing in which the en interface only becomes seen on the NWMonitor after multiple connection attempts have been made and failed. If I screen for en before connecting it simply never appears. Is there any way to handle this such that my app can intelligently wait for an en connection before trying to connect? Attaching my code although I have tried a few other setups but none has been perfect. func startMonitoringAndBrowse() { DebugLogger.shared.append("Starting Bonjour + Ethernet monitoring") if !browserStarted { let params = NWParameters.tcp params.includePeerToPeer = false params.requiredInterfaceType = .wiredEthernet browser = NWBrowser(for: .bonjourWithTXTRecord(type: "_mytcpapp._tcp", domain: nil), using: params) browser?.stateUpdateHandler = { state in if case .ready = state { DebugLogger.shared.append("Bonjour browser ready.") } } browser?.browseResultsChangedHandler = { results, _ in self.handleBrowseResults(results) } browser?.start(queue: .main) browserStarted = true } // Start monitoring for wired ethernet monitor = NWPathMonitor() monitor?.pathUpdateHandler = { path in let hasEthernet = path.availableInterfaces.contains { $0.type == .wiredEthernet } let ethernetInUse = path.usesInterfaceType(.wiredEthernet) DebugLogger.shared.append(""" NWPathMonitor: - Status: \(path.status) - Interfaces: \(path.availableInterfaces.map { "\($0.name)[\($0.type)]" }.joined(separator: ", ")) - Wired Ethernet: \(hasEthernet), In Use: \(ethernetInUse) """) self.tryToConnectIfReady() self.stopMonitoring() } monitor?.start(queue: monitorQueue) } // MARK: - Internal Logic private func handleBrowseResults(_ results: Set&lt;NWBrowser.Result&gt;) { guard !self.isResolving, !self.hasResolvedService else { return } for result in results { guard case let .bonjour(txtRecord) = result.metadata, let portString = txtRecord["actual_port"], let actualPort = Int(portString), case let .service(name, type, domain, _) = result.endpoint else { continue } DebugLogger.shared.append("Bonjour result — port: \(actualPort)") self.resolvedPort = actualPort self.isResolving = true self.resolveWithNetService(name: name, type: type, domain: domain) break } } private func resolveWithNetService(name: String, type: String, domain: String) { let netService = NetService(domain: domain, type: type, name: name) netService.delegate = self netService.includesPeerToPeer = false netService.resolve(withTimeout: 5.0) resolvingNetService = netService DebugLogger.shared.append("Resolving NetService: \(name).\(type)\(domain)") } private func tryToConnectIfReady() { guard hasResolvedService, let host = resolvedHost, let port = resolvedPort else { return } DebugLogger.shared.append("Attempting to connect: \(host):\(port)") discoveredIP = host discoveredPort = port connectionPublisher.send(.connecting(ip: host, port: port)) stopBrowsing() socketManager.connectToServer(ip: host, port: port) hasResolvedService = false } } // MARK: - NetServiceDelegate extension BonjourManager: NetServiceDelegate { func netServiceDidResolveAddress(_ sender: NetService) { guard let hostname = sender.hostName else { DebugLogger.shared.append("Resolved service with no hostname") return } DebugLogger.shared.append("Resolved NetService hostname: \(hostname)") resolvedHost = hostname isResolving = false hasResolvedService = true tryToConnectIfReady() } func netService(_ sender: NetService, didNotResolve errorDict: [String : NSNumber]) { DebugLogger.shared.append("NetService failed to resolve: \(errorDict)") } }
10
0
285
May ’25
IOS app on MacOS 15 local network access
Our app is developed for iOS, but some users also run it on macOS (as an iOS app via Apple Silicon). The app requires local network permission, which works perfectly on iOS. Previously, the connection also worked fine on macOS, but since the recent macOS update, the app can no longer connect to our device. Additionally, our app on macOS doesn't prompt for local network permission at all, whereas it does on iOS. Is this a known issue with iOS apps running on macOS? Has anyone else experienced this problem, or is there a workaround? Any help would be appreciated!
9
0
933
Oct ’25