Network connections send and receive data using transport and security protocols.

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HTTP Requests Failing on iOS Simulator but Working on Physical Devices
Hello everyone, We are currently facing an issue when testing our hybrid mobile application (built with Ionic and Angular) on the iOS Simulator. The app works perfectly on physical iOS devices — all HTTP requests complete successfully. However, when running the same build on the iOS Simulator, every HTTP request fails with the following error: { "headers": { "normalizedNames": {}, "lazyUpdate": null, "headers": {} }, "status": 0, "statusText": "Unknown Error", "url": "https://api.bizify.com.br/demo/api/ping", "ok": false, "name": "HttpErrorResponse", "message": "Http failure response for https://api.bizify.com.br/demo/api/ping: 0 Unknown Error", "error": { "isTrusted": true } } We have confirmed that the API endpoint https://api.bizify.com.br/demo/api/ping is reachable and secured with a valid SSL certificate. This issue occurs only in the iOS Simulator — not on Android devices or physical iOS devices. Has anyone encountered this issue before? Any insights on why the iOS Simulator might be blocking or failing these HTTPS requests — and how we could resolve it — would be greatly appreciated.
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Nov ’25
iOS App Store Tester Facing Network Timeouts since iOS 26?
Our iOS/iPad app is built with React Native. We use Axios as our HTTP client. Our app has been out on the app store for 2+ years and we've never had issues with reviews. Since iOS 26 came out, our app has been constantly getting rejected because the Apple tester keeps facing network timeout issues when our app makes requests to our API services. Our API stack is already configured to support IPv6 networks, and our regular user base does not run into the issues the Apple tester is seeing. None of our developers nor our internal testers have been able to reproduce the issue the Apple tester is facing. We've tried a number of things to debug the potential issue: Added a ping check on app startup. We used the native fetch present in React Native apps as well as our Axios client (with the default XHR/HTTP adapter). None of the pings make it to our API services. Added higher timeouts on app startup to let the Apple tester have more time to reach our services while their simulator device is able to connect. We've read that the environment that Apple testers use can sometimes take longer to establish an initial connection, even though packages like NetInfo from React Native report that they are connected to WiFi as soon as the app starts. Switched our Axios client adapter to use the native fetch. We did this since we noticed that Mixpanel, our tracking library, uses the native fetch in their React Native SDK and we've confirmed that requests on their end do make it through when the Apple tester is testing our app. We're running out of ideas since the issue is pretty obscure and we haven't been able to reproduce it yet, not even by following the Apple guide to set up a local IPv6 NAT64 network to be as close to their environment as possible. We've also tried testing the app while connected to VPNs from different locations to no avail. Like I said before, we noticed that this issues started for the Apple tester with the release of iOS 26, so we're wondering if there are known issues in the community that might relate to what we're experiencing. The most recent finding we've made is that some other developers report new issues with HTTP 3/QUIC on iOS. We've seen recommendations about turning off explicit support for HTTP 3 on our services, which seems to have helped other developers.
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Nov ’25
Working with a Wi-Fi Accessory
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" Working with a Wi-Fi Accessory Building an app that works with a Wi-Fi accessory presents specific challenges. This post discusses those challenges and some recommendations for how to address them. Note While my focus here is iOS, much of the info in this post applies to all Apple platforms. IMPORTANT iOS 18 introduced AccessorySetupKit, a framework to simplify the discovery and configuration of an accessory. I’m not fully up to speed on that framework myself, but I encourage you to watch WWDC 2024 Session 10203 Meet AccessorySetupKit and read the framework documentation. IMPORTANT iOS 26 introduced WiFiAware, a framework for setting up communication with Wi-Fi Aware accessories. Wi-Fi Aware is an industry standard to securely discover, pair, and communicate with nearby devices. This is especially useful for stand-alone accessories (defined below). For more on this framework, watch WWDC 2025 Session 228 Supercharge device connectivity with Wi-Fi Aware and read the framework documentation. For information on how to create a Wi-Fi Aware accessory that works with iPhone, go to Developer > Accessories, download Accessory Design Guidelines for Apple Devices, and review the Wi-Fi Aware chapter. Accessory Categories I classify Wi-Fi accessories into three different categories. A bound accessory is ultimately intended to join the user’s Wi-Fi network. It may publish its own Wi-Fi network during the setup process, but the goal of that process is to get the accessory on to the existing network. Once that’s done, your app interacts with the accessory using ordinary networking APIs. An example of a bound accessory is a Wi-Fi capable printer. A stand-alone accessory publishes a Wi-Fi network at all times. An iOS device joins that network so that your app can interact with it. The accessory never provides access to the wider Internet. An example of a stand-alone accessory is a video camera that users take with them into the field. You might want to write an app that joins the camera’s network and downloads footage from it. A gateway accessory is one that publishes a Wi-Fi network that provides access to the wider Internet. Your app might need to interact with the accessory during the setup process, but after that it’s useful as is. An example of this is a Wi-Fi to WWAN gateway. Not all accessories fall neatly into these categories. Indeed, some accessories might fit into multiple categories, or transition between categories. Still, I’ve found these categories to be helpful when discussing various accessory integration challenges. Do You Control the Firmware? The key question here is Do you control the accessory’s firmware? If so, you have a bunch of extra options that will make your life easier. If not, you have to adapt to whatever the accessory’s current firmware does. Simple Improvements If you do control the firmware, I strongly encourage you to: Support IPv6 Implement Bonjour [1] These two things are quite easy to do — most embedded platforms support them directly, so it’s just a question of turning them on — and they will make your life significantly easier: Link-local addresses are intrinsic to IPv6, and IPv6 is intrinsic to Apple platforms. If your accessory supports IPv6, you’ll always be able to communicate with it, regardless of how messed up the IPv4 configuration gets. Similarly, if you support Bonjour, you’ll always be able to find your accessory on the network. [1] Bonjour is an Apple term for three Internet standards: RFC 3927 Dynamic Configuration of IPv4 Link-Local Addresses RFC 6762 Multicast DNS RFC 6763 DNS-Based Service Discovery WAC For a bound accessory, support Wireless Accessory Configuration (WAC). This is a relatively big ask — supporting WAC requires you to join the MFi Program — but it has some huge benefits: You don’t need to write an app to configure your accessory. The user will be able to do it directly from Settings. If you do write an app, you can use the EAWiFiUnconfiguredAccessoryBrowser class to simplify your configuration process. HomeKit For a bound accessory that works in the user’s home, consider supporting HomeKit. This yields the same onboarding benefits as WAC, and many other benefits as well. Also, you can get started with the HomeKit Open Source Accessory Development Kit (ADK). Bluetooth LE If your accessory supports Bluetooth LE, think about how you can use that to improve your app’s user experience. For an example of that, see SSID Scanning, below. Claiming the Default Route, Or Not? If your accessory publishes a Wi-Fi network, a key design decision is whether to stand up enough infrastructure for an iOS device to make it the default route. IMPORTANT To learn more about how iOS makes the decision to switch the default route, see The iOS Wi-Fi Lifecycle and Network Interface Concepts. This decision has significant implications. If the accessory’s network becomes the default route, most network connections from iOS will be routed to your accessory. If it doesn’t provide a path to the wider Internet, those connections will fail. That includes connections made by your own app. Note It’s possible to get around this by forcing your network connections to run over WWAN. See Binding to an Interface in Network Interface Techniques and Running an HTTP Request over WWAN. Of course, this only works if the user has WWAN. It won’t help most iPad users, for example. OTOH, if your accessory’s network doesn’t become the default route, you’ll see other issues. iOS will not auto-join such a network so, if the user locks their device, they’ll have to manually join the network again. In my experience a lot of accessories choose to become the default route in situations where they shouldn’t. For example, a bound accessory is never going to be able to provide a path to the wider Internet so it probably shouldn’t become the default route. However, there are cases where it absolutely makes sense, the most obvious being that of a gateway accessory. Acting as a Captive Network, or Not? If your accessory becomes the default route you must then decide whether to act like a captive network or not. IMPORTANT To learn more about how iOS determines whether a network is captive, see The iOS Wi-Fi Lifecycle. For bound and stand-alone accessories, becoming a captive network is generally a bad idea. When the user joins your network, the captive network UI comes up and they have to successfully complete it to stay on the network. If they cancel out, iOS will leave the network. That makes it hard for the user to run your app while their iOS device is on your accessory’s network. In contrast, it’s more reasonable for a gateway accessory to act as a captive network. SSID Scanning Many developers think that TN3111 iOS Wi-Fi API overview is lying when it says: iOS does not have a general-purpose API for Wi-Fi scanning It is not. Many developers think that the Hotspot Helper API is a panacea that will fix all their Wi-Fi accessory integration issues, if only they could get the entitlement to use it. It will not. Note this comment in the official docs: NEHotspotHelper is only useful for hotspot integration. There are both technical and business restrictions that prevent it from being used for other tasks, such as accessory integration or Wi-Fi based location. Even if you had the entitlement you would run into these technical restrictions. The API was specifically designed to support hotspot navigation — in this context hotspots are “Wi-Fi networks where the user must interact with the network to gain access to the wider Internet” — and it does not give you access to on-demand real-time Wi-Fi scan results. Many developers look at another developer’s app, see that it’s displaying real-time Wi-Fi scan results, and think there’s some special deal with Apple that’ll make that work. There is not. In reality, Wi-Fi accessory developers have come up with a variety of creative approaches for this, including: If you have a bound accessory, you might add WAC support, which makes this whole issue go away. In many cases, you can avoid the need for Wi-Fi scan results by adopting AccessorySetupKit. You might build your accessory with a barcode containing the info required to join its network, and scan that from your app. This is the premise behind the Configuring a Wi-Fi Accessory to Join the User’s Network sample code. You might configure all your accessories to have a common SSID prefix, and then take advantage of the prefix support in NEHotspotConfigurationManager. See Programmatically Joining a Network, below. You might have your app talk to your accessory via some other means, like Bluetooth LE, and have the accessory scan for Wi-Fi networks and return the results. Programmatically Joining a Network Network Extension framework has an API, NEHotspotConfigurationManager, to programmatically join a network, either temporarily or as a known network that supports auto-join. For the details, see Wi-Fi Configuration. One feature that’s particularly useful is it’s prefix support, allowing you to create a configuration that’ll join any network with a specific prefix. See the init(ssidPrefix:) initialiser for the details. For examples of how to use this API, see: Configuring a Wi-Fi Accessory to Join the User’s Network — It shows all the steps for one approach for getting a non-WAC bound accessory on to the user’s network. NEHotspotConfiguration Sample — Use this to explore the API in general. Secure Communication Users expect all network communication to be done securely. For some ideas on how to set up a secure connection to an accessory, see TLS For Accessory Developers. Revision History 2025-11-05 Added a link to the Accessory Design Guidelines for Apple Devices. 2025-06-19 Added a preliminary discussion of Wi-Fi Aware. 2024-09-12 Improved the discussion of AccessorySetupKit. 2024-07-16 Added a preliminary discussion of AccessorySetupKit. 2023-10-11 Added the HomeKit section. Fixed the link in Secure Communication to point to TLS For Accessory Developers. 2023-07-23 First posted.
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1.9k
Nov ’25
Wi-Fi Aware Paring Flow
Hello, I understand that to discover and pair a device or accessory with Wi-Fi Aware, we can use either the DeviceDiscoveryUI or AccessorySetupKitUI frameworks. During the pairing process, both frameworks prompt the user to enter a pairing code. Is this step mandatory? What alternatives exist for devices or accessories that don't have a way to communicate a pairing code to the user (for example, devices or accessories without a display or voice capability)? Best regards, Gishan
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Nov ’25
Expected timing/delays when triggering background URLSessionTask
My app attempts to upload events and logging data when the user backgrounds the app (i.e., when applicationDidEnterBackground is triggered) by creating an uploadTask using a URLSession with a URLSessionConfiguration.background. When uploading these events after being backgrounded, we call beginBackgroundTask on UIApplication, which gives us about 25-30 seconds before the expirationHandler gets triggered. I am noticing, however, that the expirationHandler is frequently called and no upload attempts have even started. This might be reasonable if, for example, I had other uploads in progress initiated prior to backgrounding, but this is not the case. Could someone confirm that, when initiating an uploadTask while the app is backgrounded using a backgroundSession, there's really no way to predict when that upload is going to begin? My observation is that about 10-20% of the time it does not begin within 20 seconds of backgrounding, and I have many events coming from clients in the field showing as much.
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Nov ’25
Happy Eyeballs cancels also-ran only after WebSocket handshake (duplicate WS sessions)
Network.framework: Happy Eyeballs cancels also-ran only after WebSocket handshake (duplicate WS sessions) Hi everyone 👋 When using NWConnection with NWProtocolWebSocket, I’ve noticed that Happy Eyeballs cancels the losing connection only after the WebSocket handshake completes on the winning path. As a result, both IPv4 and IPv6 attempts can send the GET / Upgrade request in parallel, which may cause duplicate WebSocket sessions on the server. Standards context RFC 8305 §6 (Happy Eyeballs v2) states: Once one of the connection attempts succeeds (generally when the TCP handshake completes), all other connections attempts that have not yet succeeded SHOULD be canceled. This “SHOULD” is intentionally non-mandatory — implementations may reasonably delay cancellation to account for additional factors (e.g. TLS success or ALPN negotiation). So Network.framework’s current behavior — canceling after the WebSocket handshake — is technically valid, but it can have practical side effects at the application layer. Why this matters WebSocket upgrades are semantically HTTP GET requests (RFC 6455 §4.1). Per RFC 9110 §9.2, GET requests are expected to be safe and idempotent — they should not have side effects on the server. In practice, though, WebSocket upgrades often: include Authorization headers or cookies create authenticated or persistent sessions So if both IPv4 and IPv6 paths reach the upgrade stage, the server may create duplicate sessions before one connection is canceled. Questions / Request Is there a way to make Happy Eyeballs cancel the losing path earlier — for example, right after TCP or TLS handshake — when using NWProtocolWebSocket? If not, could Apple consider adding an option (e.g. in NWProtocolWebSocket.Options) to control the cancellation threshold, such as: after TCP handshake after TLS handshake after protocol handshake (current behavior) That would align the implementation more closely with RFC 8305 and help prevent duplicate, non-idempotent upgrade requests. Context I’m aware of Quinn’s post Understanding Also-Ran Connections. This report focuses specifically on the cancellation timing for NWProtocolWebSocket and the impact of duplicate upgrade requests. Although RFC 6455 and RFC 9110 define WebSocket upgrades as safe and idempotent HTTP GETs, in practice they often establish authenticated or stateful sessions. Thus, delaying cancellation until after the upgrade can create duplicate sessions — even though the behavior is technically RFC-compliant. Happy to share a sysdiagnose and sample project via Feedback if helpful. Thanks! 🙏 Example log output With Network Link Conditioner (Edge): log stream --info --predicate 'subsystem == "com.apple.network" && process == "WS happy eyeballs"' 2025-11-03 17:02:48.875258 [C3] create connection to wss://echo.websocket.org:443 2025-11-03 17:02:48.878949 [C3.1] starting child endpoint 2a09:8280:1::37:b5c3:443 # IPv6 2025-11-03 17:02:48.990206 [C3.1] starting child endpoint 66.241.124.119:443 # IPv4 2025-11-03 17:03:00.251928 [C3.1.1] Socket received CONNECTED event # IPv6 TCP up 2025-11-03 17:03:00.515837 [C3.1.2] Socket received CONNECTED event # IPv4 TCP up 2025-11-03 17:03:04.543651 [C3.1.1] Output protocol connected (WebSocket) # WS ready on IPv6 2025-11-03 17:03:04.544390 [C3.1.2] nw_endpoint_handler_cancel # cancel IPv4 path 2025-11-03 17:03:04.544913 [C3.1.2] TLS warning: close_notify # graceful close IPv4
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Nov ’25
How to install self signed certificate to iPhone simulator running iOS 18.5?
I am trying to communicate with the backend of my project. So I need to install the certificate into the simulator. I have the .pem file but when I drag-dropped it into the simulator, I got the error "Simulator device failed to complete the requested operation.". The simulator is an iPhone 16 Pro running iOS 18.5. Is there any way to install the cert to my simulator? PS: I can't use Apple Configurator or MDM because I am using the office's Mac. And I can't install anything there. So I can only do it manually.
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Nov ’25
[iPadOS 26] EACCES (Permission Denied) on UDP Broadcast despite Multicast Networking Entitlement
My application (using a nested framework for networking) was working correctly on iPadOS 18, but failed to perform a UDP broadcast operation after upgrading the device to iPadOS 26. The low-level console logs consistently show a "Permission denied" error. Symptoms & Error Message: When attempting to send a UDP broadcast packet using NWConnection (or a similar low-level socket call within the framework), the connection fails immediately with the following error logged in the console: nw_socket_service_writes_block_invoke [C2:1] sendmsg(fd 6, 124 bytes) [13: Permission denied] (Error code 13 corresponds to EACCES). Verification Steps (What I have checked): Multicast Networking Entitlement is Approved and Applied: The necessary entitlement (com.apple.developer.networking.multicast) was granted by Apple. The Provisioning Profile used for signing the Host App Target has been regenerated and explicitly includes "Multicast Networking" capability (see attached screenshot). I confirmed that Entitlements cannot be added directly to the Framework Target, only the Host App Target, which is the expected behavior. Local Network Privacy is Configured: The Host App's Info.plist contains the NSLocalNetworkUsageDescription key with a clear usage string. Crucially, the Local Network Access alert does not reliably appear when the Broadcast function is first called (despite a full reinstall after OS upgrade). Even when Local Network Access is manually enabled in Settings, the Broadcast still fails with EACCES. Code Implementation: The Broadcast is attempted using NWConnection to the host 255.255.255.255 on a specific port. Request: Since all required entitlements and profiles are correct, and the failure is a low-level EACCES on a newly updated OS version, I suspect this may be a regression bug in the iPadOS 26 security sandbox when validating the Multicast Networking Entitlement against a low-level socket call (like sendmsg). Has anyone else encountered this specific Permission denied error on iPadOS 26 with a valid Multicast Entitlement, and is there a known workaround aside from switching to mDNS/Bonjour?
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Oct ’25
[iPadOS 28] EACCES (Permission Denied) on UDP Broadcast despite Multicast Networking Entitlement
My application (using a nested framework for networking) was working correctly on iPadOS 18, but failed to perform a UDP broadcast operation after upgrading the device to iPadOS 28. The low-level console logs consistently show a "Permission denied" error. Symptoms & Error Message: When attempting to send a UDP broadcast packet using NWConnection (or a similar low-level socket call within the framework), the connection fails immediately with the following error logged in the console: nw_socket_service_writes_block_invoke [C2:1] sendmsg(fd 6, 124 bytes) [13: Permission denied] (Error code 13 corresponds to EACCES). Verification Steps (What I have checked): Multicast Networking Entitlement is Approved and Applied: The necessary entitlement (com.apple.developer.networking.multicast) was granted by Apple. The Provisioning Profile used for signing the Host App Target has been regenerated and explicitly includes "Multicast Networking" capability (see attached screenshot). I confirmed that Entitlements cannot be added directly to the Framework Target, only the Host App Target, which is the expected behavior. Local Network Privacy is Configured: The Host App's Info.plist contains the NSLocalNetworkUsageDescription key with a clear usage string. Crucially, the Local Network Access alert does not reliably appear when the Broadcast function is first called (despite a full reinstall after OS upgrade). Even when Local Network Access is manually enabled in Settings, the Broadcast still fails with EACCES. Code Implementation: The Broadcast is attempted using NWConnection to the host 255.255.255.255 on a specific port. Request: Since all required entitlements and profiles are correct, and the failure is a low-level EACCES on a newly updated OS version, I suspect this may be a regression bug in the iPadOS 28 security sandbox when validating the Multicast Networking Entitlement against a low-level socket call (like sendmsg). Has anyone else encountered this specific Permission denied error on iPadOS 28 with a valid Multicast Entitlement, and is there a known workaround aside from switching to mDNS/Bonjour?
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161
Oct ’25
Performance issues when using the Network API used to create a web server
Hello, We use the Network API in our macOS ObjectiveC applications to create a small web server. With macOS Sequoia or Tahoe (not with Sonoma), downloading files from another computer using the built-in ethernet port is way too slow. Steps to reproduce: Computer A (using macOS Tahoe or Sonoma), run an application using the Network APIs to create a webserver Make sure that this computer connects to the network using the Ethernet port, there is no issue when using WiFi On computer B, make an HTTP request to download a 20MB file => it will take about 30 seconds to download => way too slow... We tested with: if on computer A you run a web server using the GCD API instead of Network, it takes 0.2 seconds to download the file => no issue on computer A disable TSO, it improves the results, but that's not a long term solution as it doesn't hold when rebooting I can provide sample code to demonstrate this if needed. This is a new issue as it's been a while we use that code, and only noticed it recently, and macOS Sonoma is not impacted. Thank you for the help you can provide. Pierre
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Oct ’25
WifiAware Endpoint usage and impact on infrastructure Wifi
Are the Wifi-Aware's WAEndpoint's discovered ephemeral? I'm trying to understand what's the best way to reconnect a disconnected WifiAware connection - Can I just cache the endpoint and start a new connection with the same endpoint or do I need to browse again and get a new WAEndpoint? My use case requires both WifiAware connection to another device and the devices also need to be connected to infrastructure wifi most of the time. I'm concerned about the WifiAware's connection having any impact on infrastructure wifi. What is the impact on the infrastructure wifi here in comparison to using the Apple peer to peer wifi(That Multipeer framework or Network framework use)?
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Oct ’25
iOS App Fails to Establish Secure Connection (NSURLErrorDomain Code=-1200 SSL Error)
Hi everyone 👋 I’m running into a persistent SSL issue on iOS where the app fails to establish a secure HTTPS connection to our backend APIs. The same endpoints work fine on Android and web, but on iOS the requests fail with: Error Domain=NSURLErrorDomain Code=-1200 "An SSL error has occurred and a secure connection to the server cannot be made." UserInfo={ NSLocalizedDescription = "An SSL error has occurred and a secure connection to the server cannot be made."; _kCFStreamErrorDomainKey = 3; _kCFStreamErrorCodeKey = -9802; } 🔍 What I’ve Checked: The servers use valid, trusted SSL certificates from a public CA TLS 1.2 and 1.3 are enabled The intermediate certificates appear correctly configured (verified using SSL Labs) The issue happens on our customer's end. (Got it via Sentry) Note: We recently removed NSAppTransportSecurity(NSAllowsArbitraryLoads) on our app, since all the endpoints use valid HTTPS certificates and standard configurations. ❓ Questions: Are there additional SSL validation checks performed by iOS when ATS is enabled? Has anyone seen similar behaviour, where valid certificate chains still trigger SSL errors? Any insights or debugging suggestions would be greatly appreciated 🙏
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Oct ’25
Network devices may not be able to connect to Personal HotSpot.
Explanation of the issue When tethering is enabled and a wireless connection is established, there are instances where an IP address is not assigned. Steps to Reproduce the Issue (if possible) Enable iPhone tethering and connect wirelessly using 11ax. Expected Result The iPhone assigns an IP address, enabling network connectivity. Actual Result Observed DHCP negotiation failed. After attempting communication with the DHCP server via DHCP Discover, a DHCP Offer was returned from the iPhone. If this was missed, it would retry by performing another DHCP Discover. However, the iPhone does not issue a DHCP Offer no matter how many times it retries. The IP address is not assigned unless the wireless connection is disconnected and reconnected. If the initial Discover is missed, does this invalidate subsequent Offer retries? The above issue has been confirmed on iPhone 17 Pro and iPhone 16. It does not appear to occur on iPhone 15.
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Oct ’25
Upgrading NEFilterDataProvider Causes System Network Interruption
Hi, when I perform an overlay installation via a PKG on macOS for an application containing the NEFilterDataProvider functionality, there is a chance that the entire system network becomes unreachable. Disabling the corresponding Content Filter in "System Settings > Network > Filters" immediately restores network connectivity. This issue does not occur every time, with a frequency of approximately 1 in 20 installation attempts.  The following details may help identify the problem: The Filter.app containing the NEFilterDataProvider resides within the main app's Resources directory, e.g., /Applications/Main.app/Contents/Resources/Filter.app Main.app is installed via a PKG; the issue typically occurs during an overlay installation of Main.app. The NEFilterDataProvider operates as a System Extension. The func handleNewFlow(_ flow: NEFilterFlow) -> NEFilterNewFlowVerdict {} returns .allow. Wireshark packet captures show TCP packets but no UDP packets; TCP handshakes cannot complete. Disabling the corresponding content filter in "System Settings > Network > Filters" restores the network; re-enabling it breaks connectivity again. After waiting for a period, approximately 30-60 minutes, network connectivity can recover automatically. What causes this and how can it be fixed? Any workarounds?
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191
Oct ’25
The delay issue of 4G TCP connection for iPhone 17 in China's mobile network
Reproduce Same SIM card with 4G, same testing location, connected to the same server, xcode debugging game applications, network/profile retrotransmitted, Avg round trip to view data iPhone17, Turn off 4G and turn on WiFi. All the above indicators are acceptable iPhone17, Turn on 4G, turn off WiFi, retry with retransmission and very high Avg round trip iPhone14-16, Turn on 4G and turn off WiFi. All the above indicators are acceptable App Unity3d project .netframe4.0 C# Socket Other Many developers in Chinese forums have provided feedback on this issue
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834
Oct ’25
Network.Framework: Per-process simultaneous connection limit
We have observed a per-process limitation on the number of simultaneous nw_connection_t objects in certain macOS environments. On some systems, this limit does not appear to apply, but on others the limitation is reproducible. When a process attempts to establish a large number of connections (e.g. 512+), some connections enter the nw_connection_state_waiting state and report the POSIX error “Cannot allocate memory”. These connections remain stuck indefinitely, even after other connections are deallocated and resources should theoretically be available again. This behavior severely impacts use cases such as transparent proxies implemented via the NetworkExtension framework, which intercept system-wide traffic and must open connections on behalf of all client processes. In this scenario, a per-process limit effectively becomes a system-wide limit, leading to unexpected and hard-to-diagnose network failures in client applications. So, is there any way to disable this restriction for Network Extension processes? Are there any system settings that could affect this limitation and be modified by users?
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253
Oct ’25
Testing Family Controls & Multicast Networking APIs - Educational Use Without Paid Developer Account?
Hi Apple Engineers and fellow developers, I'm a student developer working on an educational focus management app that helps users hide distracting apps during study sessions. The app consists of: macOS app: Simple "Hide apps" button that triggers app hidding sessions iOS app: Uses Screen Time API to temporarily hide selected apps from home screen Communication: Bonjour networking between Mac and iPhone for session coordination The Challenge My app requires two entitlements that aren't available with Personal Developer Teams: com.apple.developer.family-controls (for Screen Time API) com.apple.developer.networking.multicast (for Bonjour device discovery) Current Error Messages text Cannot create a iOS App Development provisioning profile for "focuser.focuser-app". Personal development teams, including "My Name", do not support the Family Controls (Development) capability. Provisioning profile doesn't include the com.apple.developer.family-controls and com.apple.developer.networking.multicast entitlements. My Question for Apple Engineers Is there any legitimate way to test these privacy-sensitive APIs on my own devices for educational/learning purposes without purchasing the $99/year Apple Developer Program membership? I understand the security reasons behind these restrictions, but as a student just learning iOS development, it creates a significant barrier to experimenting with these technologies.
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401
Oct ’25
Network Framework: LAN vs Wifi vs Peer to Peer Wifi Switching
I would like to understand the behaviour of Network framework when I have established a connection between 2 iOS devices which are connected through LAN and the same Wifi. Assumptions: Enabled includePeerToPeer. Devices are discovered and connected through Bonjour: When the connection establishes for the first time, does it automatically decide which interface to pick? I see some posts which point to Happy Eyeball algorithm but that seem to point more towards ipv4 vs ipv6 rather than Wifi vs LAN vs P2P. In the middle of a connection, if the established connection has issues, does the Network framework automatically switch to the best available interface? If not, I would assume the app will have to handle the switching in betterPathUpdateHandler callback? I’m curious what needs to be done here. Do I just create a new connection and hope that it picks the actual better path? The NWInterface.InterfaceType doesnt have a type for peer to peer wifi. Does that mean that when the interface actually switches to peer to peer, the InterfaceType will be other? It would be great if there is a workflow or example of how this needs to be handled with multiple available Interfaces.
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121
Oct ’25
HTTP Requests Failing on iOS Simulator but Working on Physical Devices
Hello everyone, We are currently facing an issue when testing our hybrid mobile application (built with Ionic and Angular) on the iOS Simulator. The app works perfectly on physical iOS devices — all HTTP requests complete successfully. However, when running the same build on the iOS Simulator, every HTTP request fails with the following error: { "headers": { "normalizedNames": {}, "lazyUpdate": null, "headers": {} }, "status": 0, "statusText": "Unknown Error", "url": "https://api.bizify.com.br/demo/api/ping", "ok": false, "name": "HttpErrorResponse", "message": "Http failure response for https://api.bizify.com.br/demo/api/ping: 0 Unknown Error", "error": { "isTrusted": true } } We have confirmed that the API endpoint https://api.bizify.com.br/demo/api/ping is reachable and secured with a valid SSL certificate. This issue occurs only in the iOS Simulator — not on Android devices or physical iOS devices. Has anyone encountered this issue before? Any insights on why the iOS Simulator might be blocking or failing these HTTPS requests — and how we could resolve it — would be greatly appreciated.
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113
Activity
Nov ’25
Data roaming or cellular profile or shortcut
Is there a way to create a data roaming or cellular profile or shortcut so that we can turn data off for certain sets of apps when we travel (and turn them all back on when we're back)?
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Nov ’25
iOS App Store Tester Facing Network Timeouts since iOS 26?
Our iOS/iPad app is built with React Native. We use Axios as our HTTP client. Our app has been out on the app store for 2+ years and we've never had issues with reviews. Since iOS 26 came out, our app has been constantly getting rejected because the Apple tester keeps facing network timeout issues when our app makes requests to our API services. Our API stack is already configured to support IPv6 networks, and our regular user base does not run into the issues the Apple tester is seeing. None of our developers nor our internal testers have been able to reproduce the issue the Apple tester is facing. We've tried a number of things to debug the potential issue: Added a ping check on app startup. We used the native fetch present in React Native apps as well as our Axios client (with the default XHR/HTTP adapter). None of the pings make it to our API services. Added higher timeouts on app startup to let the Apple tester have more time to reach our services while their simulator device is able to connect. We've read that the environment that Apple testers use can sometimes take longer to establish an initial connection, even though packages like NetInfo from React Native report that they are connected to WiFi as soon as the app starts. Switched our Axios client adapter to use the native fetch. We did this since we noticed that Mixpanel, our tracking library, uses the native fetch in their React Native SDK and we've confirmed that requests on their end do make it through when the Apple tester is testing our app. We're running out of ideas since the issue is pretty obscure and we haven't been able to reproduce it yet, not even by following the Apple guide to set up a local IPv6 NAT64 network to be as close to their environment as possible. We've also tried testing the app while connected to VPNs from different locations to no avail. Like I said before, we noticed that this issues started for the Apple tester with the release of iOS 26, so we're wondering if there are known issues in the community that might relate to what we're experiencing. The most recent finding we've made is that some other developers report new issues with HTTP 3/QUIC on iOS. We've seen recommendations about turning off explicit support for HTTP 3 on our services, which seems to have helped other developers.
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333
Activity
Nov ’25
Working with a Wi-Fi Accessory
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" Working with a Wi-Fi Accessory Building an app that works with a Wi-Fi accessory presents specific challenges. This post discusses those challenges and some recommendations for how to address them. Note While my focus here is iOS, much of the info in this post applies to all Apple platforms. IMPORTANT iOS 18 introduced AccessorySetupKit, a framework to simplify the discovery and configuration of an accessory. I’m not fully up to speed on that framework myself, but I encourage you to watch WWDC 2024 Session 10203 Meet AccessorySetupKit and read the framework documentation. IMPORTANT iOS 26 introduced WiFiAware, a framework for setting up communication with Wi-Fi Aware accessories. Wi-Fi Aware is an industry standard to securely discover, pair, and communicate with nearby devices. This is especially useful for stand-alone accessories (defined below). For more on this framework, watch WWDC 2025 Session 228 Supercharge device connectivity with Wi-Fi Aware and read the framework documentation. For information on how to create a Wi-Fi Aware accessory that works with iPhone, go to Developer > Accessories, download Accessory Design Guidelines for Apple Devices, and review the Wi-Fi Aware chapter. Accessory Categories I classify Wi-Fi accessories into three different categories. A bound accessory is ultimately intended to join the user’s Wi-Fi network. It may publish its own Wi-Fi network during the setup process, but the goal of that process is to get the accessory on to the existing network. Once that’s done, your app interacts with the accessory using ordinary networking APIs. An example of a bound accessory is a Wi-Fi capable printer. A stand-alone accessory publishes a Wi-Fi network at all times. An iOS device joins that network so that your app can interact with it. The accessory never provides access to the wider Internet. An example of a stand-alone accessory is a video camera that users take with them into the field. You might want to write an app that joins the camera’s network and downloads footage from it. A gateway accessory is one that publishes a Wi-Fi network that provides access to the wider Internet. Your app might need to interact with the accessory during the setup process, but after that it’s useful as is. An example of this is a Wi-Fi to WWAN gateway. Not all accessories fall neatly into these categories. Indeed, some accessories might fit into multiple categories, or transition between categories. Still, I’ve found these categories to be helpful when discussing various accessory integration challenges. Do You Control the Firmware? The key question here is Do you control the accessory’s firmware? If so, you have a bunch of extra options that will make your life easier. If not, you have to adapt to whatever the accessory’s current firmware does. Simple Improvements If you do control the firmware, I strongly encourage you to: Support IPv6 Implement Bonjour [1] These two things are quite easy to do — most embedded platforms support them directly, so it’s just a question of turning them on — and they will make your life significantly easier: Link-local addresses are intrinsic to IPv6, and IPv6 is intrinsic to Apple platforms. If your accessory supports IPv6, you’ll always be able to communicate with it, regardless of how messed up the IPv4 configuration gets. Similarly, if you support Bonjour, you’ll always be able to find your accessory on the network. [1] Bonjour is an Apple term for three Internet standards: RFC 3927 Dynamic Configuration of IPv4 Link-Local Addresses RFC 6762 Multicast DNS RFC 6763 DNS-Based Service Discovery WAC For a bound accessory, support Wireless Accessory Configuration (WAC). This is a relatively big ask — supporting WAC requires you to join the MFi Program — but it has some huge benefits: You don’t need to write an app to configure your accessory. The user will be able to do it directly from Settings. If you do write an app, you can use the EAWiFiUnconfiguredAccessoryBrowser class to simplify your configuration process. HomeKit For a bound accessory that works in the user’s home, consider supporting HomeKit. This yields the same onboarding benefits as WAC, and many other benefits as well. Also, you can get started with the HomeKit Open Source Accessory Development Kit (ADK). Bluetooth LE If your accessory supports Bluetooth LE, think about how you can use that to improve your app’s user experience. For an example of that, see SSID Scanning, below. Claiming the Default Route, Or Not? If your accessory publishes a Wi-Fi network, a key design decision is whether to stand up enough infrastructure for an iOS device to make it the default route. IMPORTANT To learn more about how iOS makes the decision to switch the default route, see The iOS Wi-Fi Lifecycle and Network Interface Concepts. This decision has significant implications. If the accessory’s network becomes the default route, most network connections from iOS will be routed to your accessory. If it doesn’t provide a path to the wider Internet, those connections will fail. That includes connections made by your own app. Note It’s possible to get around this by forcing your network connections to run over WWAN. See Binding to an Interface in Network Interface Techniques and Running an HTTP Request over WWAN. Of course, this only works if the user has WWAN. It won’t help most iPad users, for example. OTOH, if your accessory’s network doesn’t become the default route, you’ll see other issues. iOS will not auto-join such a network so, if the user locks their device, they’ll have to manually join the network again. In my experience a lot of accessories choose to become the default route in situations where they shouldn’t. For example, a bound accessory is never going to be able to provide a path to the wider Internet so it probably shouldn’t become the default route. However, there are cases where it absolutely makes sense, the most obvious being that of a gateway accessory. Acting as a Captive Network, or Not? If your accessory becomes the default route you must then decide whether to act like a captive network or not. IMPORTANT To learn more about how iOS determines whether a network is captive, see The iOS Wi-Fi Lifecycle. For bound and stand-alone accessories, becoming a captive network is generally a bad idea. When the user joins your network, the captive network UI comes up and they have to successfully complete it to stay on the network. If they cancel out, iOS will leave the network. That makes it hard for the user to run your app while their iOS device is on your accessory’s network. In contrast, it’s more reasonable for a gateway accessory to act as a captive network. SSID Scanning Many developers think that TN3111 iOS Wi-Fi API overview is lying when it says: iOS does not have a general-purpose API for Wi-Fi scanning It is not. Many developers think that the Hotspot Helper API is a panacea that will fix all their Wi-Fi accessory integration issues, if only they could get the entitlement to use it. It will not. Note this comment in the official docs: NEHotspotHelper is only useful for hotspot integration. There are both technical and business restrictions that prevent it from being used for other tasks, such as accessory integration or Wi-Fi based location. Even if you had the entitlement you would run into these technical restrictions. The API was specifically designed to support hotspot navigation — in this context hotspots are “Wi-Fi networks where the user must interact with the network to gain access to the wider Internet” — and it does not give you access to on-demand real-time Wi-Fi scan results. Many developers look at another developer’s app, see that it’s displaying real-time Wi-Fi scan results, and think there’s some special deal with Apple that’ll make that work. There is not. In reality, Wi-Fi accessory developers have come up with a variety of creative approaches for this, including: If you have a bound accessory, you might add WAC support, which makes this whole issue go away. In many cases, you can avoid the need for Wi-Fi scan results by adopting AccessorySetupKit. You might build your accessory with a barcode containing the info required to join its network, and scan that from your app. This is the premise behind the Configuring a Wi-Fi Accessory to Join the User’s Network sample code. You might configure all your accessories to have a common SSID prefix, and then take advantage of the prefix support in NEHotspotConfigurationManager. See Programmatically Joining a Network, below. You might have your app talk to your accessory via some other means, like Bluetooth LE, and have the accessory scan for Wi-Fi networks and return the results. Programmatically Joining a Network Network Extension framework has an API, NEHotspotConfigurationManager, to programmatically join a network, either temporarily or as a known network that supports auto-join. For the details, see Wi-Fi Configuration. One feature that’s particularly useful is it’s prefix support, allowing you to create a configuration that’ll join any network with a specific prefix. See the init(ssidPrefix:) initialiser for the details. For examples of how to use this API, see: Configuring a Wi-Fi Accessory to Join the User’s Network — It shows all the steps for one approach for getting a non-WAC bound accessory on to the user’s network. NEHotspotConfiguration Sample — Use this to explore the API in general. Secure Communication Users expect all network communication to be done securely. For some ideas on how to set up a secure connection to an accessory, see TLS For Accessory Developers. Revision History 2025-11-05 Added a link to the Accessory Design Guidelines for Apple Devices. 2025-06-19 Added a preliminary discussion of Wi-Fi Aware. 2024-09-12 Improved the discussion of AccessorySetupKit. 2024-07-16 Added a preliminary discussion of AccessorySetupKit. 2023-10-11 Added the HomeKit section. Fixed the link in Secure Communication to point to TLS For Accessory Developers. 2023-07-23 First posted.
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Activity
Nov ’25
Wi-Fi Aware Paring Flow
Hello, I understand that to discover and pair a device or accessory with Wi-Fi Aware, we can use either the DeviceDiscoveryUI or AccessorySetupKitUI frameworks. During the pairing process, both frameworks prompt the user to enter a pairing code. Is this step mandatory? What alternatives exist for devices or accessories that don't have a way to communicate a pairing code to the user (for example, devices or accessories without a display or voice capability)? Best regards, Gishan
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474
Activity
Nov ’25
-10985 network error from urlSession
Getting -10985 error from urlSession while attempting to make a connection. Not sure why this is happening if anyone is aware please help
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239
Activity
Nov ’25
Expected timing/delays when triggering background URLSessionTask
My app attempts to upload events and logging data when the user backgrounds the app (i.e., when applicationDidEnterBackground is triggered) by creating an uploadTask using a URLSession with a URLSessionConfiguration.background. When uploading these events after being backgrounded, we call beginBackgroundTask on UIApplication, which gives us about 25-30 seconds before the expirationHandler gets triggered. I am noticing, however, that the expirationHandler is frequently called and no upload attempts have even started. This might be reasonable if, for example, I had other uploads in progress initiated prior to backgrounding, but this is not the case. Could someone confirm that, when initiating an uploadTask while the app is backgrounded using a backgroundSession, there's really no way to predict when that upload is going to begin? My observation is that about 10-20% of the time it does not begin within 20 seconds of backgrounding, and I have many events coming from clients in the field showing as much.
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153
Activity
Nov ’25
Happy Eyeballs cancels also-ran only after WebSocket handshake (duplicate WS sessions)
Network.framework: Happy Eyeballs cancels also-ran only after WebSocket handshake (duplicate WS sessions) Hi everyone 👋 When using NWConnection with NWProtocolWebSocket, I’ve noticed that Happy Eyeballs cancels the losing connection only after the WebSocket handshake completes on the winning path. As a result, both IPv4 and IPv6 attempts can send the GET / Upgrade request in parallel, which may cause duplicate WebSocket sessions on the server. Standards context RFC 8305 §6 (Happy Eyeballs v2) states: Once one of the connection attempts succeeds (generally when the TCP handshake completes), all other connections attempts that have not yet succeeded SHOULD be canceled. This “SHOULD” is intentionally non-mandatory — implementations may reasonably delay cancellation to account for additional factors (e.g. TLS success or ALPN negotiation). So Network.framework’s current behavior — canceling after the WebSocket handshake — is technically valid, but it can have practical side effects at the application layer. Why this matters WebSocket upgrades are semantically HTTP GET requests (RFC 6455 §4.1). Per RFC 9110 §9.2, GET requests are expected to be safe and idempotent — they should not have side effects on the server. In practice, though, WebSocket upgrades often: include Authorization headers or cookies create authenticated or persistent sessions So if both IPv4 and IPv6 paths reach the upgrade stage, the server may create duplicate sessions before one connection is canceled. Questions / Request Is there a way to make Happy Eyeballs cancel the losing path earlier — for example, right after TCP or TLS handshake — when using NWProtocolWebSocket? If not, could Apple consider adding an option (e.g. in NWProtocolWebSocket.Options) to control the cancellation threshold, such as: after TCP handshake after TLS handshake after protocol handshake (current behavior) That would align the implementation more closely with RFC 8305 and help prevent duplicate, non-idempotent upgrade requests. Context I’m aware of Quinn’s post Understanding Also-Ran Connections. This report focuses specifically on the cancellation timing for NWProtocolWebSocket and the impact of duplicate upgrade requests. Although RFC 6455 and RFC 9110 define WebSocket upgrades as safe and idempotent HTTP GETs, in practice they often establish authenticated or stateful sessions. Thus, delaying cancellation until after the upgrade can create duplicate sessions — even though the behavior is technically RFC-compliant. Happy to share a sysdiagnose and sample project via Feedback if helpful. Thanks! 🙏 Example log output With Network Link Conditioner (Edge): log stream --info --predicate 'subsystem == "com.apple.network" && process == "WS happy eyeballs"' 2025-11-03 17:02:48.875258 [C3] create connection to wss://echo.websocket.org:443 2025-11-03 17:02:48.878949 [C3.1] starting child endpoint 2a09:8280:1::37:b5c3:443 # IPv6 2025-11-03 17:02:48.990206 [C3.1] starting child endpoint 66.241.124.119:443 # IPv4 2025-11-03 17:03:00.251928 [C3.1.1] Socket received CONNECTED event # IPv6 TCP up 2025-11-03 17:03:00.515837 [C3.1.2] Socket received CONNECTED event # IPv4 TCP up 2025-11-03 17:03:04.543651 [C3.1.1] Output protocol connected (WebSocket) # WS ready on IPv6 2025-11-03 17:03:04.544390 [C3.1.2] nw_endpoint_handler_cancel # cancel IPv4 path 2025-11-03 17:03:04.544913 [C3.1.2] TLS warning: close_notify # graceful close IPv4
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110
Activity
Nov ’25
How to install self signed certificate to iPhone simulator running iOS 18.5?
I am trying to communicate with the backend of my project. So I need to install the certificate into the simulator. I have the .pem file but when I drag-dropped it into the simulator, I got the error "Simulator device failed to complete the requested operation.". The simulator is an iPhone 16 Pro running iOS 18.5. Is there any way to install the cert to my simulator? PS: I can't use Apple Configurator or MDM because I am using the office's Mac. And I can't install anything there. So I can only do it manually.
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3
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449
Activity
Nov ’25
[iPadOS 26] EACCES (Permission Denied) on UDP Broadcast despite Multicast Networking Entitlement
My application (using a nested framework for networking) was working correctly on iPadOS 18, but failed to perform a UDP broadcast operation after upgrading the device to iPadOS 26. The low-level console logs consistently show a "Permission denied" error. Symptoms & Error Message: When attempting to send a UDP broadcast packet using NWConnection (or a similar low-level socket call within the framework), the connection fails immediately with the following error logged in the console: nw_socket_service_writes_block_invoke [C2:1] sendmsg(fd 6, 124 bytes) [13: Permission denied] (Error code 13 corresponds to EACCES). Verification Steps (What I have checked): Multicast Networking Entitlement is Approved and Applied: The necessary entitlement (com.apple.developer.networking.multicast) was granted by Apple. The Provisioning Profile used for signing the Host App Target has been regenerated and explicitly includes "Multicast Networking" capability (see attached screenshot). I confirmed that Entitlements cannot be added directly to the Framework Target, only the Host App Target, which is the expected behavior. Local Network Privacy is Configured: The Host App's Info.plist contains the NSLocalNetworkUsageDescription key with a clear usage string. Crucially, the Local Network Access alert does not reliably appear when the Broadcast function is first called (despite a full reinstall after OS upgrade). Even when Local Network Access is manually enabled in Settings, the Broadcast still fails with EACCES. Code Implementation: The Broadcast is attempted using NWConnection to the host 255.255.255.255 on a specific port. Request: Since all required entitlements and profiles are correct, and the failure is a low-level EACCES on a newly updated OS version, I suspect this may be a regression bug in the iPadOS 26 security sandbox when validating the Multicast Networking Entitlement against a low-level socket call (like sendmsg). Has anyone else encountered this specific Permission denied error on iPadOS 26 with a valid Multicast Entitlement, and is there a known workaround aside from switching to mDNS/Bonjour?
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296
Activity
Oct ’25
[iPadOS 28] EACCES (Permission Denied) on UDP Broadcast despite Multicast Networking Entitlement
My application (using a nested framework for networking) was working correctly on iPadOS 18, but failed to perform a UDP broadcast operation after upgrading the device to iPadOS 28. The low-level console logs consistently show a "Permission denied" error. Symptoms & Error Message: When attempting to send a UDP broadcast packet using NWConnection (or a similar low-level socket call within the framework), the connection fails immediately with the following error logged in the console: nw_socket_service_writes_block_invoke [C2:1] sendmsg(fd 6, 124 bytes) [13: Permission denied] (Error code 13 corresponds to EACCES). Verification Steps (What I have checked): Multicast Networking Entitlement is Approved and Applied: The necessary entitlement (com.apple.developer.networking.multicast) was granted by Apple. The Provisioning Profile used for signing the Host App Target has been regenerated and explicitly includes "Multicast Networking" capability (see attached screenshot). I confirmed that Entitlements cannot be added directly to the Framework Target, only the Host App Target, which is the expected behavior. Local Network Privacy is Configured: The Host App's Info.plist contains the NSLocalNetworkUsageDescription key with a clear usage string. Crucially, the Local Network Access alert does not reliably appear when the Broadcast function is first called (despite a full reinstall after OS upgrade). Even when Local Network Access is manually enabled in Settings, the Broadcast still fails with EACCES. Code Implementation: The Broadcast is attempted using NWConnection to the host 255.255.255.255 on a specific port. Request: Since all required entitlements and profiles are correct, and the failure is a low-level EACCES on a newly updated OS version, I suspect this may be a regression bug in the iPadOS 28 security sandbox when validating the Multicast Networking Entitlement against a low-level socket call (like sendmsg). Has anyone else encountered this specific Permission denied error on iPadOS 28 with a valid Multicast Entitlement, and is there a known workaround aside from switching to mDNS/Bonjour?
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161
Activity
Oct ’25
Performance issues when using the Network API used to create a web server
Hello, We use the Network API in our macOS ObjectiveC applications to create a small web server. With macOS Sequoia or Tahoe (not with Sonoma), downloading files from another computer using the built-in ethernet port is way too slow. Steps to reproduce: Computer A (using macOS Tahoe or Sonoma), run an application using the Network APIs to create a webserver Make sure that this computer connects to the network using the Ethernet port, there is no issue when using WiFi On computer B, make an HTTP request to download a 20MB file => it will take about 30 seconds to download => way too slow... We tested with: if on computer A you run a web server using the GCD API instead of Network, it takes 0.2 seconds to download the file => no issue on computer A disable TSO, it improves the results, but that's not a long term solution as it doesn't hold when rebooting I can provide sample code to demonstrate this if needed. This is a new issue as it's been a while we use that code, and only noticed it recently, and macOS Sonoma is not impacted. Thank you for the help you can provide. Pierre
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465
Activity
Oct ’25
WifiAware Endpoint usage and impact on infrastructure Wifi
Are the Wifi-Aware's WAEndpoint's discovered ephemeral? I'm trying to understand what's the best way to reconnect a disconnected WifiAware connection - Can I just cache the endpoint and start a new connection with the same endpoint or do I need to browse again and get a new WAEndpoint? My use case requires both WifiAware connection to another device and the devices also need to be connected to infrastructure wifi most of the time. I'm concerned about the WifiAware's connection having any impact on infrastructure wifi. What is the impact on the infrastructure wifi here in comparison to using the Apple peer to peer wifi(That Multipeer framework or Network framework use)?
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6
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251
Activity
Oct ’25
iOS App Fails to Establish Secure Connection (NSURLErrorDomain Code=-1200 SSL Error)
Hi everyone 👋 I’m running into a persistent SSL issue on iOS where the app fails to establish a secure HTTPS connection to our backend APIs. The same endpoints work fine on Android and web, but on iOS the requests fail with: Error Domain=NSURLErrorDomain Code=-1200 "An SSL error has occurred and a secure connection to the server cannot be made." UserInfo={ NSLocalizedDescription = "An SSL error has occurred and a secure connection to the server cannot be made."; _kCFStreamErrorDomainKey = 3; _kCFStreamErrorCodeKey = -9802; } 🔍 What I’ve Checked: The servers use valid, trusted SSL certificates from a public CA TLS 1.2 and 1.3 are enabled The intermediate certificates appear correctly configured (verified using SSL Labs) The issue happens on our customer's end. (Got it via Sentry) Note: We recently removed NSAppTransportSecurity(NSAllowsArbitraryLoads) on our app, since all the endpoints use valid HTTPS certificates and standard configurations. ❓ Questions: Are there additional SSL validation checks performed by iOS when ATS is enabled? Has anyone seen similar behaviour, where valid certificate chains still trigger SSL errors? Any insights or debugging suggestions would be greatly appreciated 🙏
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256
Activity
Oct ’25
Network devices may not be able to connect to Personal HotSpot.
Explanation of the issue When tethering is enabled and a wireless connection is established, there are instances where an IP address is not assigned. Steps to Reproduce the Issue (if possible) Enable iPhone tethering and connect wirelessly using 11ax. Expected Result The iPhone assigns an IP address, enabling network connectivity. Actual Result Observed DHCP negotiation failed. After attempting communication with the DHCP server via DHCP Discover, a DHCP Offer was returned from the iPhone. If this was missed, it would retry by performing another DHCP Discover. However, the iPhone does not issue a DHCP Offer no matter how many times it retries. The IP address is not assigned unless the wireless connection is disconnected and reconnected. If the initial Discover is missed, does this invalidate subsequent Offer retries? The above issue has been confirmed on iPhone 17 Pro and iPhone 16. It does not appear to occur on iPhone 15.
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124
Activity
Oct ’25
Upgrading NEFilterDataProvider Causes System Network Interruption
Hi, when I perform an overlay installation via a PKG on macOS for an application containing the NEFilterDataProvider functionality, there is a chance that the entire system network becomes unreachable. Disabling the corresponding Content Filter in "System Settings > Network > Filters" immediately restores network connectivity. This issue does not occur every time, with a frequency of approximately 1 in 20 installation attempts.  The following details may help identify the problem: The Filter.app containing the NEFilterDataProvider resides within the main app's Resources directory, e.g., /Applications/Main.app/Contents/Resources/Filter.app Main.app is installed via a PKG; the issue typically occurs during an overlay installation of Main.app. The NEFilterDataProvider operates as a System Extension. The func handleNewFlow(_ flow: NEFilterFlow) -> NEFilterNewFlowVerdict {} returns .allow. Wireshark packet captures show TCP packets but no UDP packets; TCP handshakes cannot complete. Disabling the corresponding content filter in "System Settings > Network > Filters" restores the network; re-enabling it breaks connectivity again. After waiting for a period, approximately 30-60 minutes, network connectivity can recover automatically. What causes this and how can it be fixed? Any workarounds?
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191
Activity
Oct ’25
The delay issue of 4G TCP connection for iPhone 17 in China's mobile network
Reproduce Same SIM card with 4G, same testing location, connected to the same server, xcode debugging game applications, network/profile retrotransmitted, Avg round trip to view data iPhone17, Turn off 4G and turn on WiFi. All the above indicators are acceptable iPhone17, Turn on 4G, turn off WiFi, retry with retransmission and very high Avg round trip iPhone14-16, Turn on 4G and turn off WiFi. All the above indicators are acceptable App Unity3d project .netframe4.0 C# Socket Other Many developers in Chinese forums have provided feedback on this issue
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2
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834
Activity
Oct ’25
Network.Framework: Per-process simultaneous connection limit
We have observed a per-process limitation on the number of simultaneous nw_connection_t objects in certain macOS environments. On some systems, this limit does not appear to apply, but on others the limitation is reproducible. When a process attempts to establish a large number of connections (e.g. 512+), some connections enter the nw_connection_state_waiting state and report the POSIX error “Cannot allocate memory”. These connections remain stuck indefinitely, even after other connections are deallocated and resources should theoretically be available again. This behavior severely impacts use cases such as transparent proxies implemented via the NetworkExtension framework, which intercept system-wide traffic and must open connections on behalf of all client processes. In this scenario, a per-process limit effectively becomes a system-wide limit, leading to unexpected and hard-to-diagnose network failures in client applications. So, is there any way to disable this restriction for Network Extension processes? Are there any system settings that could affect this limitation and be modified by users?
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253
Activity
Oct ’25
Testing Family Controls & Multicast Networking APIs - Educational Use Without Paid Developer Account?
Hi Apple Engineers and fellow developers, I'm a student developer working on an educational focus management app that helps users hide distracting apps during study sessions. The app consists of: macOS app: Simple "Hide apps" button that triggers app hidding sessions iOS app: Uses Screen Time API to temporarily hide selected apps from home screen Communication: Bonjour networking between Mac and iPhone for session coordination The Challenge My app requires two entitlements that aren't available with Personal Developer Teams: com.apple.developer.family-controls (for Screen Time API) com.apple.developer.networking.multicast (for Bonjour device discovery) Current Error Messages text Cannot create a iOS App Development provisioning profile for "focuser.focuser-app". Personal development teams, including "My Name", do not support the Family Controls (Development) capability. Provisioning profile doesn't include the com.apple.developer.family-controls and com.apple.developer.networking.multicast entitlements. My Question for Apple Engineers Is there any legitimate way to test these privacy-sensitive APIs on my own devices for educational/learning purposes without purchasing the $99/year Apple Developer Program membership? I understand the security reasons behind these restrictions, but as a student just learning iOS development, it creates a significant barrier to experimenting with these technologies.
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401
Activity
Oct ’25
Network Framework: LAN vs Wifi vs Peer to Peer Wifi Switching
I would like to understand the behaviour of Network framework when I have established a connection between 2 iOS devices which are connected through LAN and the same Wifi. Assumptions: Enabled includePeerToPeer. Devices are discovered and connected through Bonjour: When the connection establishes for the first time, does it automatically decide which interface to pick? I see some posts which point to Happy Eyeball algorithm but that seem to point more towards ipv4 vs ipv6 rather than Wifi vs LAN vs P2P. In the middle of a connection, if the established connection has issues, does the Network framework automatically switch to the best available interface? If not, I would assume the app will have to handle the switching in betterPathUpdateHandler callback? I’m curious what needs to be done here. Do I just create a new connection and hope that it picks the actual better path? The NWInterface.InterfaceType doesnt have a type for peer to peer wifi. Does that mean that when the interface actually switches to peer to peer, the InterfaceType will be other? It would be great if there is a workflow or example of how this needs to be handled with multiple available Interfaces.
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121
Activity
Oct ’25