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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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Changes to Personal Hotspot in iOS 18.0
We've been directed here by Quinn in DTS. We use multicast/broadcast messages extensively in our physical products for discovery purposes. If, for whatever reason, our customers cannot get this to work on their home Wi-Fi network, we advise that they connect to an iPhone hotspot to confirm behaviour and perform firmware updates as needed. As of iOS 18, we're seeing odd behaviour when using Personal Hotspot. Interestingly, we're also seeing that client devices connected to the Hotspot network are not showing a Subnet Mask in the Wi-Fi Details screen in the iOS Settings app - I don't know if that's related. We're also seeing that screen show an IP address of 192.0.0.2 for all client iPhones connected to an iPhone Hotspot. Getting more specific, we're seeing that multicast messages are no longer being received by clients when connected to an iPhone Hotspot where the iPhone running the hotspot is running iOS 18.0 or newer. By "multicast", I mean we're using a BSD socket to send data to 255.255.255.255 I've confirmed that our app has the multicast entitlement, the user has granted Local Network permission, and we've created a small sample app that demonstrates this behaviour perfectly - when connected to any other test network, multicast messages are received correctly by clients. We've also confirmed that this behaviour doesn't happen when the iPhone running the hotspot is running older iOS versions. We've tried a number of iOS 17.x releases and a number of iOS 16.x releases specifically with our sample app, but have been using this exact code since our app's original iOS 9 deployment target and have had no issues until now.
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491
Jan ’25
EAWiFiUnconfiguredAccessoryBrowser "Accessory Setup" UI selects blank/null SSID by default
We've received several reports of a new bug while setting up our products with WAC. The Accessory Setup UI appears with a blank network selected and the message 'This accessory will be set up to join "(null)".' at top. The user can tap "Show Other Networks..." to select another network, but this experience is very confusing. Why does this UI present a choice that is known to be invalid when other valid choices exist? I've captured a screenshot and sysdiagnose from this case. In most cases this problem happens only intermittently, but I can reproduce it consistently by disconnecting my iPhone from any WiFi network (WiFi remains enabled). My suggestion for a better user experience is that this UI should select the default network according to these rules: The network to which iPhone is currently connected. Any network which is in the known/my list for this iPhone Any valid network I believe rule #1 is the existing behavior, but applying rules #2 and #3 as fallbacks would be an improvement. Is there anything I can change in my iOS code or in my accessory's WAC server to improve this experience?
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178
Sep ’25
iOS VPN Issue -Disconnecting VPN from Packet Tunnel Network Extension Causes Loss of Internet Connectivity
Feedback Ticket: FB13812251 Problem Statement: We are currently facing internet connectivity issue with our VPN application where we try to disconnect the VPN from the Packet Tunnel Network Extension using - (void)cancelTunnelWithError:(nullable NSError *)error. Which API to use to disconnect the VPN from Packet Tunnel as VPN app is not running such that device retains its internet connectivity as soon as VPN disconnects. Configuration: We have configured PacketTunnelProvider with the following settings: (NETunnelProviderManager *)tunnelProvider.protocolConfiguration.includeAllNetworks = YES; (NETunnelProviderManager *)tunnelProvider.protocolConfiguration.excludeLocalNetworks = NO; (NETunnelProviderManager *)tunnelProvider.protocolConfiguration.enforceRoutes = NO; These settings are applied from the VPN app and allow us to successfully establish a VPN connection, with all traffic being routed through the tunnel as expected.We are setting above properties to address local net attack. Issue we are facing: However, we encounter a problem when we attempt to disconnect the VPN from. When we call the following method from PacketTunnel network extension: (void)cancelTunnelWithError:(nullable NSError *)error Upon calling this method, the VPN disconnects as expected, but the device loses all internet connectivity and is unable to access any resources. This is not the desired behavior. Observation : Interestingly, when we call the following method from the app side. The VPN disconnects and the device retains its internet connectivity. [enabledConfig.connection stopVPNTunnel]; We would like to achieve the same behavior when disconnecting the VPN from the Network Extension. So we are looking for an API that could be called from NE without causing any internet connectivity issue. Any guidance on how to resolve this issue would be greatly appreciated.
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665
Apr ’25
How to configure macOS app permission MANUALLY (not GUI)
I need to run multiple, slightly different copies of a modeling tool, which all need access to a model repository on a different machine. Security Settings -> Network tends to pick one modeling tool (and unfortunately the wrong one) for permission, but the dialog offers no way to add the other copies manually. Where can I configure the permission on low level. [macOS Sequoia 15.6.1]
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Sep ’25
Using Cellular Data While Connected to Wifi
Hello, A quick background: I am developing an App that receives a data stream from a device through its Wi-Fi network. The device itself is not connected to the internet, so the app won't be either. Now, I am adding a new feature to the App that would require internet connection during the data stream. Consequently, my users would need to use their cellular data. On later versions of iPhone, the phone would occasionally detect the lack of internet connection and asks the user via a pop-up if they want to use their cellular data. However, this behavior is not consistent. So my question is- can we programmatically invoke this pop-up so the user can connect to the internet? Or even better- can we program the App to use cellular data while still being connected to a Wi-Fi network? Note: I have seen mixed answers on the internet whether this is doable or not, and I know that users are able do it themselves by manually configuring their IP in their WiFi settings page, but I doubt this operation can be done through the App for security reasons. Thanks!
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3.0k
Apr ’25
Network extension not loading on MacOS Sonoma 14.7.8
Hi! When starting my app which is loading a Content Filter Network Extension I am getting the following error : sysextd: <bundle_id> : extension failed category property check: extensions belonging to the com.apple.system_extension.endpoint_security category require a later version of operating system to launch ... OSSystemExtensionRequest didFailWithError for <bundle_id> : The operation couldn’t be completed. (OSSystemExtensionErrorDomain error 9.) This is happening on a VM running Sonoma 14.7.8. I upgraded the VM to the latest available OS and the system extension is loading just fine. My question is : reading the documentation, I understand that the Network Extensions are supported starting with macOS 10.10+. Why is this not working on my Sonoma 14.7.8 VM?
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120
Sep ’25
URLSession QUIC configuration
I want to configure one aspect of my networking configuration (the QUIC keepalive interval). This only seems to be configurable via Network.framework’s nw_quic_set_keepalive_interval. Is there any way to apply this to a URLSession? Or do I need to implement the whole connection management myself using Network.framework?
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827
Jan ’25
Network Extension (App Extension) Not Launching
I'm having a lot of trouble just getting a basic network extension startup, I have a main application that creates the configuration and requests the app extension based network extension to launch. The network extension implements a NEPacketTunnelProvider and the application doesn't receive an error when starting the tunnel but when I inspect the networkextension system logs, I keep getting errors and the network extension itself doesn't appear to start nor does it log anything. log stream --predicate 'subsystem == "com.apple.networkextension"' neagent: (NetworkExtension) [com.apple.networkextension:] Extension request with extension $(BUNDLE_ID) started with identifier (null) neagent: (NetworkExtension) [com.apple.networkextension:] Failed to start extension $(BUNDLE_ID): Error Domain=NSCocoaErrorDomain Code=4097 "connection to service named $(BUNDLE_ID)" UserInfo={NSDebugDescription=connection to service named $(BUNDLE_ID)} nesessionmanager: [com.apple.networkextension:] Validation failed - no audit tokens nesessionmanager: [com.apple.networkextension:] NEVPNTunnelPlugin($(BUNDLE_ID)[inactive]): Validation of the extension failed The network extension is written in Objective-C as it needs to integrate with another language. It's not entirely clear what kind of executable the network extension is meant to be, is it meant to have a main entrypoint, or is it supposed to be a shared library / bundle?
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178
Sep ’25
Content Filters on devices without family controls authorisation.
I’m working on an iOS parental-control app that needs to block specific network traffic (e.g. certain domains or URLs). We’ve already obtained the Family Controls entitlement (since our app is explicitly a parental-control solution), but we do not use MDM to supervise devices. In testing, our NEFilterDataProvider extension only activates when the device is enrolled under a managed Family Controls profile. I am aware that we can use a PacketTunnel to achieve this but i was wondering if there is any simpler solution to this? Thanks for you time!
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174
Jun ’25
Choosing interface for multicast UDP
Hi all. Title says it all really. I have an app on MacOS that sends multicast UDP to multiple iOS devices. It shows realtime bar numbers of music played back by a playback software. It was all working until I tried a direct ethernet connection between Mac and phone - a scenario that would be quite common in the theatre world where machines dont have internet connection and people dont rely on wifi. How can I choose which interface my app sends the data through? Here is my connection function: func openConnection() { let params = NWParameters.udp params.allowLocalEndpointReuse = true params.includePeerToPeer = true let endpoint = NWEndpoint.hostPort(host: host, port: port) let conn = NWConnection(to: endpoint, using: params) self.connection = conn conn.stateUpdateHandler = { state in switch state { case .ready: print("Multicast connection ready to \(self.host)") UDPClient.console.log("Multicast connection ready to \(self.host)") case .failed(let error): print("Multicast connection failed: \(error)") default: break } } let udpQueue = DispatchQueue(label: "UDPClientQueue") conn.start(queue: udpQueue) } Thanks for any help in advance!
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70
Jun ’25
Network Extension App for MacOS with 3 Extensions
Hi All, I am currently working on a Network Extension App for MacOS using 3 types of extensions provided by Apple's Network Extension Framework. Content Filter, App Proxy (Want to get/capture/log all HTTP/HTTPS traffic), DNS Proxy (Want to get/capture/log all DNS records). Later parse into human readable format. Is my selection of network extension types correct for the intended logs I need? I am able to run with one extension: Main App(Xcode Target1) <-> Content Filter Extension. Here there is a singleton class IPCConnection between App(ViewController.swift) which is working fine with NEMachServiceName from Info.plist of ContentFilter Extension(Xcode Target2) However, when I add an App Proxy extension as a new Xcode Target3, I think the App and extension's communication getting messed up and App not getting started/Crashing. Here, In the same Main App, I am adding new separate IPCConnection for this extension. Here is the project organization/folder structure. MyNetworkExtension ├──MyNetworkExtension(Xcode Target1) │ ├── AppDelegate.swift │ ├── Assets.xcassets │ ├── Info.plist │ ├── MyNetworkExtension.entitlement │ | ── Main │ |-----ViewController.swift │ └── Base.lproj │ └── Main.storyboard ├── ContentFilterExtension(Xcode Target2) │ ├── ContentFilterExtension.entitlement │ │ ├── FilterDataProvider.swift │ │ ├── Info.plist │ │ ├── IPCConnection.swift │ │ └── main.swift ├── AppProxyProviderExtension(Xcode Target3) │ ├── AppProxyProviderExtension.entitlement │ │ ├── AppProxyIPCConnection.swift │ │ ├── AppProxyProvider.swift │ │ ├── Info.plist │ │ └── main.swift └── Frameworks ├── libbsm.tbd └── NetworkExtension.framework Is my Approach for creating a single Network Extension App with Multiple extensions correct or is there any better approach of project organization that will make future modifications/working easier and makes the maintenance better? I want to keep the logic for each extension separate while having the same, single Main App that manages everything(installing, activating, managing identifiers, extensions, etc). What's the best approach to establish a Communication from MainApp to each extension separately, without affecting one another? Is it good idea to establish 3 separate IPC Connections(each is a singleton class) for each extension? Are there any suggestions you can provide that relates to my use case of capturing all the network traffic logs(including HTTP/HTTPS, DNS Records, etc), especially on App to Extension Communication, where my app unable to keep multiple IPC Connections and maintain them separately? I've been working on it for a while, and still unable to make the Network Extension App work with multiple extensions(each as a new Xcode target). Main App with single extension is working fine, but if I add new extension, App getting crashed. I suspect it's due to XPC/IPC connection things! I really appreciate any support on this either directly or by any suggestions/resources that will help me get better understand and make some progress. Please reach out if in case any clarifications or specific information that's needed to better understand my questions. Thank you very much
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Sep ’25
Investigating CFNetwork Crashes on Older macOS Versions
CFNetwork None CFURLResponseGetRecommendedCachePolicy None 0 CFNetwork None CFHTTPCookieStorageUnscheduleFromRunLoop None 0 CFNetwork None /_/_CFNetworkAgentMessageProcessorMain None 0 CFNetwork None CFURLDownloadCancel None 0 CFNetwork None CFURLDownloadCancel None 0 libdispatch.dylib None /_dispatch/_block/_async/_invoke2 None We've observed intermittent crashes in our production environment, exclusively affecting customers running macOS 10.15 and 11. The crash logs consistently show a stack trace involving CFHTTPCookieStorageUnscheduleFromRunLoop and CFURLDownloadCancel within the CFNetwork framework. This suggests potential issues with cookie storage management and/or URL download cancellation. Could the team please analyze these crash logs and provide insights into: The root cause of the crashes. Potential race conditions or synchronization issues. Recommendations for mitigating or resolving the problem. Your assistance in resolving this issue is greatly appreciated."
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256
Mar ’25
Connecting to a service found by Bonjour isn't working.
I'm using NWBrowser to search for a server that I hosted. The browser does find my service but when it tries to connect to it, it gets stuck in the preparing phase in NWConnection.stateUpdateHandler. When I hardcode the local IP address of my computer (where the server is hosted) into NWConnection it works perfectly fine and is able to connect. When it gets stuck in the preparing phase, it gives me the warnings and error messages in the image below. You can also see that the service name is correct and it is found. I have tried _http._tcp and _ssh._tcp types and neither work. This is what my code looks like: func findServerAndConnect(port: UInt16) { print("Searching for server...") let browser = NWBrowser(for: .bonjour(type: "_ssh._tcp", domain: "local."), using: .tcp) browser.browseResultsChangedHandler = { results, _ in print("Found results: \(results)") for result in results { if case let NWEndpoint.service(name, type_, domain, interface) = result.endpoint { if name == "PocketPadServer" { print("Found service: \(name) of type \(type_) in domain \(domain) on interface \(interface)") // Construct the full service name, including type and domain let fullServiceName = "\(name).\(type_).\(domain)" print("Full service name: \(fullServiceName), \(result.endpoint)") self.connect(to: result.endpoint, port: port) browser.cancel() break } } } } browser.start(queue: .main) } func connect(to endpoint: NWEndpoint, port: UInt16) { print("Connecting to \(endpoint) on port \(port)...") // endpoint = NWEndpoint( let tcpParams = NWProtocolTCP.Options() tcpParams.enableFastOpen = true tcpParams.keepaliveIdle = 2 let params = NWParameters(tls: nil, tcp: tcpParams) params.includePeerToPeer = true // connection = NWConnection(host: NWEndpoint.Host("xx.xxx.xxx.xxx"), port: NWEndpoint.Port(3000), using: params) connection = NWConnection(to: endpoint, using: params) connection?.pathUpdateHandler = { path in print("Connection path update: \(path)") if path.status == .satisfied { print("Connection path is satisfied") } else { print("Connection path is not satisfied: \(path.status)") } } connection?.stateUpdateHandler = { newState in DispatchQueue.main.async { switch newState { case .ready: print("Connected to server") self.pairing = true self.receiveMessage() case .failed(let error): print("Connection failed: \(error)") self.isConnected = false case .waiting(let error): print("Waiting for connection... \(error)") self.isConnected = false case .cancelled: print("Connection cancelled") self.isConnected = false case .preparing: print("Preparing connection...") self.isConnected = false default: print("Connection state changed: \(newState)") break } } } connection?.start(queue: .main) }
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104
Apr ’25
Allow "Browser" to find devices on local networks
Hi, I am developing the browser based on Chromium, which initially relies on the nw_browser stack for discovering locally available network resources. We have observed an issue where, after each software update—specifically, whenever additional files are written into the application bundle—a popup appears requesting the user to allow local network access, even if this permission was already granted. The behavior is reproducible: simply overwriting files in the app bundle (we are using rsync as Chromium), even while the application is already running, causes the prompt to reappear. We have also noticed that Chromium itself exhibits the same behavior. Also I found the mess in system settings, it has several Google Chrome for example: https://www.loom.com/share/da401f39ab134628807d77f1ca3185f5?from_recorder=1&focus_title=1 We would like to provide a smoother experience for our users and avoid confusing them with repeated permission prompts. Could you please advise on possible approaches or best practices to improve our update mechanism in this regard?
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249
Sep ’25
Hide OS logs coming out of the Network framework (category: com.apple.network)
I'm establishing a connection with NWListener and NWConnection which is working great. However, if the listener disappears, a lot of logs are appearing: Is there a way to hide these logs? I'm aware of OS_ACTIVITY_MODE=disabled, but that will also hide a lot of other logs. I also know you can hide these using Xcode's filtering. I'm looking for a programmatically way to hide these completely. I'm not interested in seeing these at all, or, at least, I want to be in control. Thanks!
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120
Apr ’25
Crash within com.apple.CFNetwork.Connection , specifically due to EXC_BAD_ACCESS KERN_INVALID_ADDRESS.
Crash within com.apple.CFNetwork.Connection , specifically due to EXC_BAD_ACCESS KERN_INVALID_ADDRESS. The crash occurred within the nghttp2_session_del() function indicating a problem with the nghttp2 library, which is commonly used for HTTP/2 communication. This points towards a memory management issue. EXC_BAD_ACCESS generally signifies that the application attempted to access memory it didn't have permission to access, often caused by using a pointer after it has been freed or pointing to an invalid memory address. ** Crashed: com.apple.CFNetwork.Connection 0 libapple_nghttp2.dylib 0xa6ec nghttp2_session_del + 124 1 CFNetwork 0xace4c + 428 2 CFNetwork 0xacc80 + 36 3 libdispatch.dylib 0x2370 _dispatch_call_block_and_release + 32 4 libdispatch.dylib 0x40d0 _dispatch_client_callout + 20 5 libdispatch.dylib 0xb6d8 _dispatch_lane_serial_drain + 744 6 libdispatch.dylib 0xc214 _dispatch_lane_invoke + 432 7 libdispatch.dylib 0xd670 _dispatch_workloop_invoke + 1732 8 libdispatch.dylib 0x17258 _dispatch_root_queue_drain_deferred_wlh + 288 9 libdispatch.dylib 0x16aa4 _dispatch_workloop_worker_thread + 540 10 libsystem_pthread.dylib 0x4c7c _pthread_wqthread + 288 11 libsystem_pthread.dylib 0x1488 start_wqthread + 8 ** The stack trace does not point to any code within our product codebase, hence making it difficult to pinpoint the root cause of the issue as there are multiple network calls running concurrently during the app's runtime.
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446
Jan ’25
Building a custom VPN application from scratch
Hi there, I'm trying to build a MacOS VPN application from scratch. My VPN application is slightly from normal ones, It will include an authentication token and underlying process information (pid, application path etc.) in each connection made to the VPN gateway. Consider it a poor man's zerotrust implementation. NetworkExtension and PacketTunnel is a must, thus to retrieve process information via audit tokens. However, I'm unable to find any working examples that can be built on MacOS 15.X. I tried to open an TSI case but didn't receive anything useful. Anyone?
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209
Mar ’25
Fixed Private Wi-Fi Address Changes after Update
I had noticed that my slaac address changed between one beta and the other, but wasn't sure. Now with the RC 15.4 RC (24E247) I made point of preserving the info before updating from the previous beta. What I noticed is that not only the slaac address changes, but also the my ether address, even though I have it on Fixed in the settings. Is it expected that the ether, and the slaac, not be rotated after a OS update?
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63
Mar ’25