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

Networking Documentation

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Alternatives to nettop for Monitoring Process Network Usage on macOS
Hi everyone, I am developing an application for macOS and need to monitor the network usage (bytes sent and received) of specific processes. Previously, I used the nettop command to achieve this, but I found that it leads to high CPU usage, often reaching 95%. I'm looking for alternative methods to obtain the network usage information of processes. This could be through a different command or an available macOS API. Any suggestions or guidance on more efficient ways to gather this data would be greatly appreciated. Thank you!
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386
Jun ’24
Network framework and background tasks
Hi team, I'm working on an MQTT client for Apple platforms (macOS, iOS, and possibly tvOS and watchOS). I would like the client to listen to messages even when the application is in the background. I would appreciate any suggestions on the best approach to achieve this. Based on iOS Background Execution Limits, it seems that my best bet is to use a long-running background process with BGProcessingTaskRequest while setting up the connection. Does that sound like the right approach? Is there any limits for the bg tasks? I currently have a working BSD socket. I'm not sure if it is necessary to switch to the Network Framework to have the background task working, but I'm open to switching if it's necessary. If the approach works, does that mean I could built a http client to process large upload/download tasks without using NSURLSession? As I'm working on a cross platform project, it would be benefit if I dont need a separate http client implementation for Apple. Any insights on this topic would be greatly appreciated. Additionally, it's off topic, but the link to "WWDC 2020 Session 10063 Background Execution Demystified" (https://developer.apple.com/videos/play/wwdc2020/10063/) is broken. Is there a way to access the content there? Thanks in advance for your help and insights!
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1.2k
Jun ’24
iOS App udp and local network permission
Recently, my application was having trouble sending udp messages after it was reinstalled. The cause of the problem was initially that I did not grant local network permissions when I reinstalled, I was aware of the problem, so udp worked fine after I granted permissions. However, the next time I repeat the previous operation, I also do not grant local network permissions, and then turn it back on in the Settings, and udp does not work properly (no messages can be sent, the system version and code have not changed). Fortunately, udp worked after rebooting the phone, and more importantly, I was able to repeat the problem many times. So I want to know if the process between when I re-uninstall the app and deny local network permissions, and when I turn it back on in Settings, is that permissions have been granted normally, and not fake, and not required a reboot to reset something for udp to take effect. I'm not sure if it's the system, or if it's a similar situation as described here, hopefully that will help me find out
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1.3k
Jun ’24
How to reset Local Network Privacy settings?
On macOS 15, if a program installed in /Applications is allowed to connect to a PostgreSQL server on another machine on the local network, a program launched in debug mode from Xcode is not allowed to connect to the local network, and no prompt appears. Although it is possible to turn off registered programs in Local Network Privacy in Beta 2, permissions for programs launched from Xcode cannot be obtained at all. Does anyone know how to solve this problem?
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2.2k
Jun ’24
iOS VPN: Loss of Internet Connectivity on iOS Device post Packet Tunnel Crashes
Title: Loss of Internet Connectivity on iOS Device When Packet Tunnel Crashes Feedback ticket: https://feedbackassistant.apple.com/feedback/14162605 Product: iPhone 12 Version: iOS - 17.5.1 Configuration: NETunnelProviderManager Configuration Description: We are developing an iOS VPN client and have configured our packet tunnel provider according to Apple's guidelines. The configuration is as follows: includeAllNetworks = YES excludeLocalNetworks = NO enforceRoutes = NO This setup works as expected when the VPN successfully connects. However, we encounter a blocker issue where the device loses internet connectivity if the packet tunnel crashes. Steps to Reproduce: Configure the NETunnelProviderManager with the above settings. Connect the VPN, which successfully establishes a connection. Verify that resources are accessible and internet connectivity is functional. Packet tunnel to crash unexpectedly.Observe that the NE process (Packet Tunnel) restarts automatically, as expected and attempts to reconnect the VPN; however, the device now lacks internet connectivity, preventing VPN reconnection. Try accessing resources using Safari or any other internet-dependent app, resulting in an error indicating the device is not connected to the internet. Actual Results: The device loses internet connectivity after the packet tunnel crashes and fails to regain it automatically, preventing the VPN from reconnecting. Expected Results: The device should maintain internet connectivity or recover connectivity to allow the VPN to reconnect successfully after the packet tunnel process restarts. Workaround - iPhone device needs a restart to regain internet connectivity .
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545
Jul ’24
Network Connection on watchOS App
I am developing a watchOS-only app, and whenever I attempt to make a network request, it always fails and throws the following error: Error Domain=NSURLErrorDomain Code=-1009 "The Internet connection appears to be offline." I noticed that when I turn off Wi-Fi and Bluetooth in the settings of the iPhone paired with the Apple Watch (thus disconnecting the Apple Watch from the iPhone), my app can successfully connect to the network. Additionally, when the app contains both an iOS app and a watchOS app, after granting network permissions on the iOS app, the watchOS app can access the network normally when connected to the iPhone. When opening some system apps on the Apple Watch (such as the "Workout" app), the app will display a network permission request similar to that on iOS, but this request does not automatically pop up when my watchOS app attempts to access the network. Is there a way to request network permissions in a watchOS-only app so that it can access the network while connected to the iPhone?
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1.1k
Jul ’24
Crash in connection loader from CFNetwork with stack traces referring to internal Apple SDKs
We found there is a significant crash reports (most of them are from iOS 17, the rest are iOS 16 and 15) comes from network loader from CFNetwork. Apparently it seems there are two types of crashes if we checked from the stack trace, the one we found from both Xcode organizer and 3rd party crash reporter is referring to URLConnectionLoader::loadWithWhatToDo and the other one from our 3rd party crash reporter (didn’t found the report from Xcode organizer) referring to _CFURLResponseCreateFromArchiveList (this one only happened on iOS 17.5 and later devices). It seems that they are both kinda similar which might point to the same root cause. From what I’ve seen, we never touch the lower level API directly, we usually use the URLSession to manage our API request. The crashed stack trace also didn’t give any indication about which of our app code that triggered the crash, it only shows calls to Apple’s internal SDKs so we are unsure how to approach this issue meanwhile the crash event already reached 800+ in the last 30 days. Unfortunately, we cannot reproduce the issue as the stack trace itself seems unclear to us. I have submitted a report through feedback assistant with number: FB14679252. Would appreciate if anyone can give any advice on what we can do to avoid this in the future and probably any hint on why it could happened. Hereby I attached the crash reports that we found each from Xcode crash report and our 3rd party crash reporter (the report said it crashed on com.apple.CFNetwork.LoaderQ) so you could get a glimpse of the similarity. Xcode crash report xcode crash report.crash 3rd party crash report 3rd party crash report.txt
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1.5k
Aug ’24
Unable to recover after URLSession encounters the SSL error -9816
For years our iOS apps have experienced a networking problem, which blocks them connecting to our servers via their API endpoint domains. How can we recover after the scenario described below? Using 3rd party error logging solutions, which have different endpoint domains, we can record the error: NSUnderlyingError": Error Domain=kCFErrorDomainCFNetwork Code=-1200 "(null)" UserInfo={_kCFStreamPropertySSLClientCertificateState=0, _kCFNetworkCFStreamSSLErrorOriginalValue=-9816, _kCFStreamErrorDomainKey=3, _kCFStreamErrorCodeKey=-9816, _NSURLErrorNWPathKey=satisfied (Path is satisfied), viable, interface: pdp_ip0[lte], ipv4, dns, expensive, uses cell}, "_NSURLErrorFailingURLSessionTaskErrorKey": LocalDataTask <DEDBFA4D-810D-4438-A6A0-95E3B9668B9E>.<308>, "_kCFStreamErrorDomainKey": 3, "_NSURLErrorRelatedURLSessionTaskErrorKey": <__NSSingleObjectArrayI 0x301f82e60>( LocalDataTask <DEDBFA4D-810D-4438-A6A0-95E3B9668B9E>.<308> ) "NSLocalizedDescription": An SSL error has occurred and a secure connection to the server cannot be made., "NSLocalizedRecoverySuggestion": Would you like to connect to the server anyway? -9816 is the "server closed session with no notification" error based on comments in CoreFoundation source files. Subsequent API endpoint calls to the same domain return the same error. The SSL error occurs most prevalently after a server outage. However, despite our best efforts, we have been unable to replicate triggering the problem for development purposes via experiments with our server. When the error occurs the users report that: Fully closing (i.e. not just sending to background) and reopening the app does NOT clear connectivity to our server being blocked. Problem seems more prevalent when using mobile/cell data. Switching from mobile/cell data to WIFI resolves the connection problem and then switching back to mobile/cell data shows the problem again. So the underlying problem is not cleared. All other apps on the same device and mobile/cell data or WIFI connection, like Safari, have no problems connecting to the Internet. Deleting and reinstalling, or updating (when an update is available) resolves the problem. Or after waiting a few days the problem seems to resolve itself. The last two point above suggest that something is persisted/cached in the app preventing it from connecting properly with subsequent network attempts. Notes: We have one shared instance of the URLSession in the app for its networking because we are aware of the perils of multiple URLSession instances. We recently added conditions to call the URLSession await reset() method when detecting the SLL errors before repeating the request. It is debatable whether this reduces the problem as we still see logged cases with the subsequent requests hitting the same -9816 error. URLSession configuration: let config = URLSessionConfiguration.default config.timeoutIntervalForResource = 22 config.timeoutIntervalForRequest = 20 config.requestCachePolicy = .reloadIgnoringLocalCacheData config.urlCache = nil
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1.4k
Aug ’24
Allow "App" to find the devices on local network?
Hi, On macOS 15 beta 7, we get a network popup while launching application, "Allow "App" to find the devices on local network?" This popup we are not seeing in older versions of macOS. We also see a a new option in "System Settings->Privacy & Security->Local Network". Is there way to add the application entry in "Local Network" through a command so that we can suppress this popup on launching the applications? Regards Prema Kumar
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12k
Aug ’24
Simulator unable to connect to localhost, working fine when opened directly in laptop
I am trying to connect to localhost:8081 from simulator, but it is unable to connect with following logs: info 12:07:49.167248+0530 com.apple.WebKit.Networking nw_resolver_host_resolve_callback [C8.1] flags=0x40000003 ifindex=0 error=NoSuchRecord(-65554) hostname=localhost. addr=IN6ADDR_ANY ttl=60 info 12:07:49.167310+0530 com.apple.WebKit.Networking nw_resolver_host_resolve_callback [C8.1] flags=0x40000002 ifindex=0 error=NoSuchRecord(-65554) hostname=localhost. addr=INADDR_ANY ttl=108002 Macos 14.6.1 iOS simulator version 17.5 Som observations localhost:8081 does not load on simulator but 0.0.0.0:8081 loads fine, also 127.0.0.0:8081 loads fine on simulator. My laptop is a managed device with network filter Switching network sometimes fixes the issue. Restarting laptop sometimes fixes the issue. localhost:8081 opens find on laptop, but not on simulator. Contents of my laptop's /etc/hosts: ## # Host Database # # localhost is used to configure the loopback interface # when the system is booting. Do not change this entry. ## 127.0.0.1 localhost 255.255.255.255 broadcasthost ::1 localhost
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2.4k
Aug ’24
Using MPSession sendResource Progress in a SwiftUI ProgressView causes crash
When transferring files in a Multipeer Session, using the Progress instances (returned by either sendResource in the sender or the delegate method session(didStartReceiving:) on the receiver) in a SwiftUI ProgressView will eventually cause a crash (EXC_BAD_ACCESS in swift_retain on com.apple.MCSession.syncQueue) I have created a small sample project that demonstrates the problem. It can be found at: https://github.com/eidria/Multipeer-Progress-Demo.git. A screen shot of the stack trace from a crash (crash.jpg) is in the “Images” folder. STEPS TO REPRODUCE Run the sample on two different hosts connected to the same network (project contains both iOS & macOS targets, bug manifests in any combination). When the second instance comes up, they will automatically find and connect to each other. When the “Send Files” button is enabled, clicking it will cause the sender to repeatedly send the file “Image.HEIC” from the “Images” folder to the receiver, which deletes it upon receipt of a successful transfer (i.e. delegate call back is called with a nil error). Subsequent transfers are triggered when the sender receives notice that the prior send completed successfully. Eventually, after some (usually small) number of files have been transferred, either the sender or receiver will crash in the middle of a transfer, with EXC_BAD_ACCESS in swift_retain on com.apple.MCSession.syncQueue. Commenting out the ProgressView in the file FileTransferView.swift will allow the apps to run in perpetuity.
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728
Sep ’24
Network Local Privacy pop-up on macos Sequoia
Starting from macOS 15 (macOS Sequoia), a new pop-up is triggered: “Local Network Privacy.” We have some questions regarding this new pop-up on MacOS: Running the following simple code: cups_dest_t *dests; int num_dests = cupsGetDests(&amp;dests); triggers the “Local Network Privacy” pop-up. Question: Is this intended behavior? Even if the user presses the “Deny” button, printers can still be iterated, and it is possible to set options for the printer. Is this intended behavior? If so, which actions related to the CUPS library will be denied when the user presses the “Deny” button? Question: Should this pop-up appear for daemons/launchd processes? We found similar questions on some forums, but the answers are unclear. It seems that the pop-up should not appear for launch daemons. We tested the mentioned code with CUPS, and the pop-up was triggered. Is this a bug? If so, will it be resolved before the new macOS version is released? Question: There is somewhere documented all the scenarios in which this pop-up may appear is challenging? Regarding automatically allowing or disallowing the pop-up: We found the following response: “There is no way to automatically allow or disallow the local network privacy prompt. If it shows up in your app, you will need to analyze your code to better understand how the prompt is being triggered. If the prompt is triggered by a library you do not control, you will need to either remove the library or inquire further with the library vendor.” Question: How can we ensure that a launchd daemon will work as expected if the user presses the “Deny” button? Is there any way to detect if the user pressed “Deny”?
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1.9k
Sep ’24
Error 0x6f - Invalid or missing Program/ProgramArguments
We have an iOS app which includes a packet tunnel provider network extension. We have noticed on rare occasions that the VPN fails to start when we try to start the VPN from the app after installing it. However, rebooting the device or reinstalling the app fixes the issue. When creating the sysdiagnose file, we found some strange messages, a snippet is given below: 2024-09-10 13:40:20.291430 +0100 launchd Could not find and/or execute program specified by service: 2: No such file or directory: /private/var/containers/Bundle/Application/2FA92604-C67D-490D-8E8E-00F8D6FBF990/Sample.app/PlugIns/Tunnel.appex/Tunnel error 2024-09-10 13:40:20.291456 +0100 launchd Service could not initialize: access(/private/var/containers/Bundle/Application/2FA92604-C67D-490D-8E8E-00F8D6FBF990/Sample.app/PlugIns/Tunnel.appex/Tunnel, X_OK) failed with errno 2 - No such file or directory, error 0x6f - Invalid or missing Program/ProgramArguments We encountered this before several months ago on iOS 17.4 and reported it when the issue occurred, but this issue continues to be present in the iOS 18 release candidate. Is there any solution for this issue? Feedback ID: FB13714761
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571
Sep ’24
RCS failing on iOS 18 when VPN active
When a VPN is active, RCS messaging does not work on iOS 18. I work on an iOS VPN app, and we were very appreciative of the excludeCellularServices network flag that was released during the iOS 16 cycle. It's a great solution to ensure the VPN doesn't interfere with cellular network features from the cellular provider. Separately - As a user, I'm excited that iOS 18 includes RCS messaging. Unfortunately, RCS messaging is not working when our VPN is active (when checking on the iOS 18 release candidate). My guess is that RCS is not excluded from the VPN tunnel, even when excludeCellularServices is true. It seems like RCS should be added in this situation, as it is a cell provider service. Can RCS be added as a service that is excluded from the VPN tunnel when excludeCellularServices is true? (I've also sent this via feedback assistant, as 15094270.)
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2.3k
Sep ’24
Local Network permission prompt for daemon on macOS 15
Hi Team, OS is prompting for local network permission for our application which runs as root level daemon. As per the our analysis, it looks like it is prompting from our own library which is trying to get network info ' using /usr/sbin/system_profiler with "-xml -detailLevel basic SPNetworkDataType" and then trying to iterate to find DNS.ServerAddresses for each item. Then using [NSHost hostWithAddress:IPAddress];(When this library is not linked to the app then there is no prompt, so most likely this is the code that is resulting in the prompt). Is this expected ? . Is there any other way that we can get DNS host name without being prompted for local network permission on mac OS 15
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4.0k
Sep ’24
iOS 18 Per-App VPN: "Deactivate Configuration" Button Behavior
We’ve noticed that in iOS 18, the "Deactivate Configuration" button within the Per-App VPN settings immediately disables the VPN for selected apps without any confirmation prompt. This can be problematic for users, as there is no warning or verification before the action is taken, which may lead to unintended disruptions in VPN connectivity. We haven’t found any relevant documentation on Apple’s developer website addressing this behavior. Any insights or suggestions would be greatly appreciated and if we can have documentation to disable this button using MDM profile it will be great
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2.9k
Sep ’24
Ventura to Sequoia upgrade snafus firewall options
ISSUE Upgrading a macOS Ventura host to Sequoia results in the attached three issues visible in either of the two screen shot: Whether or not "Block all incoming connections" is enabled, a small subset of connections are hard-wired to "Allow incoming connections"; It is not possible to remove the hard-wired "Allow incoming connections" (e.g., selecting the row, the "-" button at bottom left is not available"; and After the upgrade to Sequoia, SidecarRelay was set to "Block incoming connections". QUESTIONs a) What terminal level commands should be used to remove the hard-wired "Allow incoming connections"? b) What other integrity checks should I run on the firewall configuration to see if other aspects of its operations are now botched? FB15074003 tracks the issues noted above.
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818
Sep ’24
macOS 15 Network Extension Incompatibilities?
Users are reporting that 3rd-party software that leverages Apple's Network Extensions (such as LuLu and Windows Defender) are causing networking issues after upgrading to macOS 15. However as such products were working seamlessly on macOS 14.* and nothing in the code of these products changed between then and now, this would point to bug in macOS. Users have mentioned the following work arounds: Disabling the internal (macOS) firewall Upgrading to macOS 15.1 beta More info about the issues and these "workarounds" here and here.. Looking for any guidance / insight / technical details from Apple, as users are (understandably) blaming these tools and their developers 😭 Of course if there are updated APIs or some other changes in macOS 15 that developers should consider / conform to, to ensure compatibility that'd be great to know too!
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3.4k
Sep ’24
App crash after update to IOS 18
After update to IOS18, my app crashed. following is the exception got from xcode: Trapped uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSFileManager createDirectoryAtURL:withIntermediateDirectories:attributes:error:]: URL is nil' ( 0 CoreFoundation 0x0000000194a79098 47427277-EE15-3C17-AD68-6886B0380B5E + 540824 1 libobjc.A.dylib 0x0000000191d7b2e4 objc_exception_throw + 88 2 Foundation 0x0000000193741f48 12E17A7A-B65F-35EE-82D7-CBC31004E223 + 1154888 3 CFNetwork 0x0000000195eeb2bc FA95B718-E8EB-34BD-90FA-8FB1AFE016D6 + 164540 4 CFNetwork 0x0000000195eeac7c FA95B718-E8EB-34BD-90FA-8FB1AFE016D6 + 162940 5 libdispatch.dylib 0x000000010342a71c _dispatch_client_callout + 20 6 libdispatch.dylib 0x000000010343bf04 _dispatch_lane_barrier_sync_invoke_and_complete + 176 7 CFNetwork 0x0000000195eeaa88 FA95B718-E8EB-34BD-90FA-8FB1AFE016D6 + 162440 8 CFNetwork 0x0000000195ee9b20 FA95B718-E8EB-34BD-90FA-8FB1AFE016D6 + 158496 9 CFNetwork 0x0000000195ee95f4 FA95B718-E8EB-34BD-90FA-8FB1AFE016D6 + 157172 10 CFNetwork 0x0000000195ee907c FA95B718-E8EB-34BD-90FA-8FB1AFE016D6 + 155772 11 CFNetwork 0x0000000195ee34b0 FA95B718-E8EB-34BD-90FA-8FB1AFE016D6 + 132272 12 CFNetwork 0x0000000195f942c4 FA95B718-E8EB-34BD-90FA-8FB1AFE016D6 + 856772 13 CFNetwork 0x0000000195f94214 FA95B718-E8EB-34BD-90FA-8FB1AFE016D6 + 856596 14 CFNetwork 0x0000000195f9330c FA95B718-E8EB-34BD-90FA-8FB1AFE016D6 + 852748 15 libdispatch.dylib 0x0000000103428a30 _dispatch_call_block_and_release + 32 16 libdispatch.dylib 0x000000010342a71c _dispatch_client_callout + 20 17 libdispatch.dylib 0x00000001034325e8 _dispatch_lane_serial_drain + 828 18 libdispatch.dylib 0x0000000103433394 _dispatch_lane_invoke + 460 19 libdispatch.dylib 0x0000000103434b20 _dispatch_workloop_invoke + 2264 20 libdispatch.dylib 0x00000001034405f0 _dispatch_root_queue_drain_deferred_wlh + 328 21 libdispatch.dylib 0x000000010343fc00 _dispatch_workloop_worker_thread + 580 22 libsystem_pthread.dylib 0x000000021bddfc7c _pthread_wqthread + 288 23 libsystem_pthread.dylib 0x000000021bddc488 start_wqthread + 8 ) This app works fine until ios 18 appear. Could you help me? thanks
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4.2k
Sep ’24