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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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Local Network permission appears to be ignored after reboot, even though it was granted
We have a Java application built for macOS. On the first launch, the application prompts the user to allow local network access. We've correctly added the NSLocalNetworkUsageDescription key to the Info.plist, and the provided description appears in the system prompt. After the user grants permission, the application can successfully connect to a local server using its hostname. However, the issue arises after the system is rebooted. When the application is launched again, macOS does not prompt for local network access a second time—which is expected, as the permission was already granted. Despite this, the application is unable to connect to the local server. It appears the previously granted permission is being ignored after a reboot. A temporary workaround is to manually toggle the Local Network permission off and back on via System Settings > Privacy & Security, which restores connectivity—until the next reboot. This behavior is highly disruptive, both for us and for a significant number of our users. We can reproduce this on multiple systems... The issues started from macOS Sequoia 15.0 By opening the application bundle using "Show Package Contents," we can launch the application via "JavaAppLauncher" without any issues. Once started, the application is able to connect to our server over the local network. This seems to bypass the granted permissions? "JavaAppLauncher" is also been used in our Info.plist file Removing the following plist in Recovery Mode seems to resolve the issue rm "/Volumes/Macintosh HD/Library/Preferences/com.apple.networkextension.plist" Is this safe to do?
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53
Jul ’25
Socket Becomes Unresponsive in Local Connectivity Extension After Lock Screen
I’m developing an app designed for hospital environments, where public internet access may not be available. The app includes two components: the main app and a Local Connectivity Extension. Both rely on persistent TCP socket connections to communicate with a local server. We’re observing a recurring issue where the extension’s socket becomes unresponsive every 1–3 hours, but only when the device is on the lock screen, even if the main app remains in the foreground. When the screen is not locked, the connection is stable and no disconnections occur. ❗ Issue Details: • What’s going on: The extension sends a keep-alive ping packet every second, and the server replies with a pong and a system time packet. • The bug: The server stops receiving keep alive packets from the extension.  • On the server, we detect about 30 second gap on the server, a gap that shows no packets were received by the extension. This was confirmed via server logs and Wireshark).  • On the extension, from our logs there was no gap in sending packets. From it’s perspective, all packets were sent with no error.  • Because no packet are being received by the server, no packets will be sent to the extension. Eventually the server closes the connection due to keep-alive timeout.  • FYI we log when the NEAppPushProvider subclass sleeps and it did NOT go to sleep while we were debugging. 🧾 Example Logs: Extension log: 2025-03-24 18:34:48.808 sendKeepAliveRequest() 2025-03-24 18:34:49.717 sendKeepAliveRequest() 2025-03-24 18:34:50.692 sendKeepAliveRequest() ... // continuous sending of the ping packet to the server, no problems here 2025-03-24 18:35:55.063 sendKeepAliveRequest() 2025-03-24 18:35:55.063 keepAliveTimer IS TIME OUT... in CoreService. // this is triggered because we did not receive any packets from the server 2025-03-24 18:34:16.298 No keep-alive received for 16 seconds... connection ID=95b3... // this shows that there has been no packets being received by the extension ... 2025-03-24 18:34:30.298 Connection timed out on keep-alive. connection ID=95b3... // eventually closes due to no packets being received 2025-03-24 18:34:30.298 Remote Subsystem Disconnected {name=iPhone|Replica-Ext|...} ✅ Observations: • The extension process continues running and logging keep-alive attempts. • However, network traffic stops reaching the server, and no inbound packets are received by the extension. • It looks like the socket becomes silently suspended or frozen, without being properly closed or throwing an error. ❓Questions: • Do you know why this might happen within a Local Connectivity Extension, especially under foreground conditions and locked ? • Is there any known system behavior that might cause the socket to be suspended or blocked in this way after running for a few hours? Any insights or recommendations would be greatly appreciated. Thank you!
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75
Mar ’25
Creating another nw_endpoint_t/nw_connection_t from an existing one, to change port number
I'm able to discover a service with Bonjour, which gets me an nw_browse_result_t from which I can get an nw_endpoint_t and then an nw_connection_t. That's all fine. But this particular service runs on 3 ports. The port numbers of the other 2 ports are in the txt record (but they are well-known and stable anyway). How can I create 2 more nw_connection_t to the same host/IP but on a different port? I already have this working with NSNetService, but am trying to update to Network.framework. I've found nw_endpoint_get_address() but the docs say it returns null "if the endpoint is not of type nw_endpoint_type_address" and indeed nw_browse_result_t gives me an nw_endpoint_type_bonjour_service.
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78
Mar ’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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180
May ’25
Seeking Recommended Approach for Sharing VPN Profile Private Keys Between Sandboxed macOS App and Packet Tunnel System Extension
Hello Apple Developer Community, We are developing a full-tunnel VPN app for macOS that utilizes a packet tunnel network system extension (via NEPacketTunnelProvider). We're committed to using a system extension for this purpose, as it aligns with our requirements for system-wide tunneling. The app is sandboxed and intended for distribution on the Mac App Store. Here's the workflow: The app (running in user context) downloads a VPN profile from our server. It generates private keys, appends them to the profile, and attempts to save this enhanced profile securely in the keychain. The packet tunnel system extension (running in root context) needs to access this profile, including the private keys, to establish the VPN connection. We've encountered challenges in securely sharing this data across the user-root boundary due to sandbox restrictions and keychain access limitations. Here's what we've tried so far, along with the issues: Writing from the App to the System Keychain: Attempted to store the profile in the system keychain for root access. This fails because the sandboxed app lacks permissions to write to the system keychain. (We're avoiding non-sandboxed approaches for App Store compliance.) Extension Reading Directly from the User Login Keychain: Tried having the extension access the user's login keychain by its path. We manually added the network extension (located in /Library/SystemExtensions//bundle.systemextension) to the keychain item's Access Control List (ACL) via Keychain Access.app for testing. This results in "item not found" errors, likely due to the root context not seamlessly accessing user-keychain items without additional setup. Using Persistent References in NETunnelProviderProtocol: The app stores the profile in the user keychain and saves a persistent reference (as Data) in the NETunnelProviderProtocol's identityReference or similar fields. The extension then attempts to retrieve the item using this reference. We manually added the network extension (located in /Library/SystemExtensions//bundle.systemextension) to the keychain item's Access Control List (ACL) via Keychain Access.app for testing. However, this leads to error -25308 (errSecInteractionNotAllowed) when the extension tries to access it, possibly because of the root-user context mismatch or interaction requirements. Programmatically Adding the Extension to the ACL: Explored using SecAccess and SecACL APIs to add the extension as a trusted application. This requires SecTrustedApplicationCreateFromPath to create a SecTrustedApplicationRef from the extension's path. Issue 1: The sandboxed app can't reliably obtain the installed extension's path (e.g., via scanning /Library/SystemExtensions or systemextensionsctl), as sandbox restrictions block access. Issue 2: SecTrustedApplicationCreateFromPath is deprecated since macOS 10.15, and we're hesitant to rely on it for future compatibility. We've reviewed documentation on keychain sharing, access groups (including com.apple.managed.vpn.shared, but we're not using managed profiles/MDM) as the profiles are download from a server, and alternatives like XPC for on-demand communication, but we're unsure if XPC is suitable for sensitive data like private keys during tunnel creation. And if this is recommended what is going to be the approach here. What is the recommended, modern approach for this scenario? Is there a non-deprecated way to handle ACLs or share persistent references across contexts? Should we pursue a special entitlement for a custom access group, or is there a better pattern using NetworkExtension APIs? Any insights, code snippets, or references to similar implementations would be greatly appreciated. We're targeting macOS 15+. Thanks in advance!
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106
Aug ’25
When adding a VPN configuration, the Settings app doesn't continue with the configuration process
Sometimes when adding a VPN configuration, it just redirects to the Settings app and doesn’t continue with the rest of the configuration process like prompting for passcode. But it proceeds as normal after the 2nd or 3rd try. This issue is occurring on iOS 18.5 build 22F5068a but it has been a problem over several versions now. Feedback ID: FB17458055
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145
May ’25
Network connection works in cmd Line app but not SwiftUI app
I'm writing a SwiftUI LDAP Browser. I built a command line swift app to do some testing and it works fine. I had to add the certificates from the LDAP server to the system keychain before it would work with TLS/SSL. Then I ported the same code into a SwiftUI app but I cannot get it to connect via TLS/SSL. On the same machine with the same certs it errors with: An unexpected error occurred: message("Can't contact LDAP server") It connect fine with our TLS/SSL. I suspect this may have to do with App Transport Security. Can anyone point me in the right direction to resolve this? App is MacOS only.
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275
Jan ’25
Background Download Support for Large Video Files in visionOS App
Hi everyone, I'm developing a visionOS app that allows users to download large video files (similar to a movie download experience, with each file being around 10 GB). I've successfully implemented the core video download functionality using URLSession, and everything works as expected while the app is active. Now, I’m looking to support background downloading. Specifically, I want users to be able to start a download and then leave the app (e.g., switch apps or return to the home screen) while the download continues in the background. Additionally, I’d like to confirm a specific scenario: If the user starts a download, then removes the headset (keeping the device turned on and connected to power), will the download continue in the background? Or does visionOS suspend the app or downloads in this case? I’m considering using a background URLSessionConfiguration (as done in iOS/macOS) to enable this behavior, but I’m not sure if it behaves the same way on visionOS or if there are special limitations or best practices when handling large downloads on this platform. Any insights or official guidance would be greatly appreciated! Thanks!
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86
May ’25
IOS VPN APP DEPLOYMENT
Hi everyone, I developed an Android version of a VPN app built with Flutter using OpenVPN, and it works perfectly on Android. However, when porting it to iOS, I’ve encountered an issue: the app connects successfully but then automatically disconnects when tested via TestFlight. We’ve already added all the necessary network extensions. Despite this, we decided to submit the app to the App Store. It’s been five days now, and the app is still 'Waiting for Review.' Could anyone share their experience deploying and working on an iOS version of a VPN app? I’d really appreciate your insights!
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115
Mar ’25
Can we create a MDM profile for Transparent Proxy without remote server address
We have an application which is written in Swift, which activates network extension (Transparent Proxy). We want to use MDM deployment for this network system extension. Our Transparent Proxy module is a system extension, which is exposing an app proxy provider interface (We are using NETransparentProxyProvider class and in extension’s Info.plist we use com.apple.networkextension.app-proxy key.) We don’t have any remote server setup to forward the traffic, instead we open a connection with a certain localhost:port to redirect the traffic which is received in our transparent proxy. We have another module that listens to the particular localhost:port to process the traffic further. As per https://developer.apple.com/documentation/devicemanagement/vpn/transparentproxy documentation, we noticed that we can use the VPN payload with app-proxy as Provider Type for Transparent Proxy. We were able to install the profile created via Jamf Pro and also while in stalling our product the Transparent Proxy gets mapped with the one which is installed via profile. However after that the network is broken and hence unable to browse anything. We are suspecting the remote server filed is causing this. So we tried creating the custom profile without remote server address for VPN payload, but we are unable to install the profile. It throws below error: 2025-02-11 16:43:55.193348+0530 0x2f880 Error 0x0 6815 0 mdmclient: (NetworkExtension) [com.apple.networkextension:] Failed to save configuration DGWebProxy because it is invalid: Error Domain=NEConfigurationErrorDomain Code=2 "configuration is invalid: Missing server address" UserInfo={NSLocalizedDescription=configuration is invalid: Missing server address}
2025-02-11 16:43:55.193376+0530 0x2f880 Error 0x0 6815 0 mdmclient: (NetworkExtension) [com.apple.networkextension:] NEProfileIngestion Error occurred when saving configuration 'DGWebProxy': configuration is invalid: configuration is invalid: Missing server address 
2025-02-11 16:43:55.196159+0530 0x2f880 Error 0x0 6815 7 mdmclient: [com.apple.ManagedClient:CPDomainPlugIn] [ERROR] [0:MDMDaemon:CPDomainPlugIn:<0x2f880>] <<<<< PlugIn: InstallPayload [NEProfileIngestionPlugin] Error: Error Domain=ConfigProfilePluginDomain Code=-319 "The ‘VPN Service’ payload could not be installed. The VPN service could not be created." UserInfo={NSLocalizedDescription=The ‘VPN Service’ payload could not be installed. The VPN service could not be created.} <<<<<
2025-02-11 16:43:55.196826+0530 0x2f880 Error 0x0 6815 7 mdmclient: [com.apple.ManagedClient:MDMDaemon] [ERROR] [0:MDMDaemon:<0x2f880>] [CE] PlugIn_InstallPayload ==> Error Domain=ConfigProfilePluginDomain Code=-319 "The ‘VPN Service’ payload could not be installed. The VPN service could not be created." UserInfo={NSLocalizedDescription=The ‘VPN Service’ payload could not be installed. The VPN service could not be created.} Can we create MDM profile for Transparent Proxy without remote server address?
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447
Feb ’25
Behavior of Pending Receive Callbacks on Canceled NWConnection (UDP) Registered to Custom Serial Dispatch Queue
Hi Everyone, I’m working on a communication system for my app using NWConnection with the UDP protocol. The connection is registered to a custom serial dispatch queue. However, I’m trying to understand what the behavior will be in a scenario where the connection is canceled while there are still pending receive operations in progress. Scenario Overview: The sender is transmitting n = 100 packets to the receiver, out of which 40 packets have already been sent (i.e., delivered to the Receiver). The receiver has posted m = 20 pending receive operations, where each receive operation is responsible for handling one packet. The receiver has already successfully processed x = 10 packets. At the time of cancellation, the receiver’s buffer still holds m = 20 packets that are pending for processing, and k = 10 pending receive callbacks are in the dispatch queue, waiting to be executed. At same time when the 10th packet was processed another thread triggers .cancel() on this accepted NWConnection (on the receiver side), I need to understand the impact on the pending receive operations and their associated callbacks. My Questions: What happens to the k = 10 pending receive callbacks that are in the dispatch queue waiting to be triggered when the connection is canceled? Will these callbacks complete successfully and process the data? Or, because the connection is canceled, will they complete with failure? What happens to the remaining pending receive operations that were initiated but have not yet been scheduled in the dispatch queue? For the pending receive operations that were already initiated (i.e., the network stack is waiting to receive the data, but the callback hasn’t been scheduled yet), will they fail immediately when the connection is canceled? Or is there any chance that the framework might still process these receives before the cancellation fully takes effect?
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326
Feb ’25
NEFilterManager.shared().loadFromPreferences never invoke completionHandler
NEFilterManager.shared().loadFromPreferences { loadError in DispatchQueue.global.async { ... } } the code above is executed in an app-like deamon and completionHandler was never invoked, same code in an application works fine.(they are both packed with content filter network system extension) is it because of the restriction of app-like deamon?
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396
Jan ’25
Input required on choice of HTTPS server stack on Apple Platforms for programmatic integration
We have a requirement to create a production quality application that also acts as HTTPS server for certain communication. The preference is for the server to support HTTP/1.1, HTTP/2 and HTTP/3 communication asynchronously, though not mandatory to support all the HTTP versions. Wanted to get the guidance, on which stack should be used, that is most reliable and that gives the maximum long term compatibility, sustainability and reliability. What is the recommended 'in-built' or 'available by default' stack on Apple Platform ? For HTTPS on HTTP/1.1 with synchronous mode operations ? For HTTPS on HTTP/1.1 with asynchronous mode operations ? For HTTPS on HTTP/2 with synchronous mode operations ? For HTTPS on HTTP/2 with asynchronous mode operations ? For HTTPS on HTTP/3 with asynchronous mode operations ? For HTTPS on HTTP/1.1 + HTTP/2 with synchronous mode operations ? For HTTPS on HTTP/1.1 + HTTP/2 with asynchronous mode operations ? For HTTPS on HTTP/1.1 + HTTP/2 + HTTP/3 with asynchronous mode operations ? What the generally recommended server stack that a typical application uses whether 'in-built' or 'available by default on Apple ' or 'not-available by default on Apple' stack. From the available stacks , we tried to evaluate the below stacks: https://opensource.apple.com/projects/swiftnio/ : We understand that while it’s not preinstalled as part of Apple's OSes, it is an official Swift package supported by Apple and can easily be added to your project. At the moment it supports HTTP/1.1 and HTTP/2. The link https://github.com/apple/swift-nio/issues/1730says that HTTP/3 will get added in the future. Is there any other HTTPS stack (built-in or third-party) that is recommended to the used on Apple's platform ? Our application is expected to be working on macOS, iOS, iPadOS, tvOS and watchOS. We understand that macOS also includes Apache HTTPD server. As our application is not primarily a Web Server (and also supports other protocols both in client and server mode), it looks integrating HTTPS directly into the application using a lightweight HTTP library with SSL/TLS support is a better option, in place of Apache HTTPD. From the document we know that swift-nio uses BoringSSL (swift-nio-ssl) which is prepackaged along with the swift-nio library, and it does not use the default Secure Transport. What is the reason being not using Secure Transport ? Now does it become the responsibility of the application using swift-nio to take care of updating BoringSSL with the patches.
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302
Feb ’25
Wifi SSID Detection
I have a single ssid that I would like to connect users to, which I can do easily with the NetworkExtension api. The only additional feature I want to add is being able to detect the availability of the ssid before connecting to it. I have checked the forums and looked through things like the Hotspot Helper Docs. From what I can tell, this just isn't possible. So, two questions I have: Is this definitely impossible? Any recommended alternatives for simulating this type of behavior? Thanks!
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251
Jan ’25
New developer question - exporting Apple Watch data to central server
This is probably a basic question but I wanted to ask your advice for the best way to take consenting users' Watch data from Apple Health Kit and send it to our central server? One idea we had was to create an iOS app that gets the data from Apple's Health SDK on the phone and sends it to our server. Would appreciate any help here, thank you.
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69
Jun ’25
PolicyDenied on Simulator with Xcode 16 and Network Framework NWBrowser
I'm using Network framework for communication between devices. The first time I instantiate an NWBrowser, it will prompt the user with a popup that says: Allow &lt;app name&gt; to find devices on local networks? The problem is, once I upgraded from Xcode 15.4 to Xcode 16.4, the popup doesn't appear; it says in the debug window: nw_browser_fail_on_dns_error_locked [B1] nw_browser_dns_service_browse_callback failed: PolicyDenied(18,446,744,073,709,486,046) I do have the info.plist keys Privacy-Local Network Usage Description (NSLocalNetworkUsageDescription) and Bonjour Services (NSBonjourServices) so it's not that. Also, It still works on a real device. I think something changed with Xcode 16 that tightened the security on a simulator, or maybe disabled Network framework entirely. It's not the firewall on my computer because that is turned off. I'm using an M1 MacBook Pro.
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136
Jun ’25
Determine outgoing flow source IPs without allowing data leakage using NEFilterDataProvider
I'm looking for help with a network extension filtering issue. Specifically, we have a subclass of NEFilterDataProvider that is used to filter flows based upon a set of rules, including source IP and destination IP. We've run into an issue where the source IP is frequently 0.0.0.0 (or the IPv6 equivalent) on outgoing flows. This has made it so rules based upon source IP don't work. This is also an issue as we report these connections, but we're lacking critical data. We were able to work around the issue somewhat by keeping a list of flows that we allow that we periodically check to see if the source IP is available, and then report after it becomes available. We also considered doing a "peekBytes" to allow a bit of data to flow and then recheck the flow, but we don't want to allow data leakage on connections that should be blocked because of the source IP. Is there a way to force the operating system or network extension frameworks to determine the source IP for an outbound flow without allowing any bytes to flow to the network? STEPS TO REPRODUCE Create a network filtering extension for filtering flows using NEFilterDataProvider See that when handleNewFlow: is called, the outgoing flow lacks the source IP (is 0.0.0.0) in most cases There is this post that is discussing a similar question, though for a slightly different reason. I imagine the answer to this and the other post will be related, at least as far as NEFilterDataProvider:handleNewFlow not having source IP is considered. Thanks!
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146
Apr ’25