General: Forums subtopic: App & System Services > Networking TN3151 Choosing the right networking API Networking Overview document — Despite the fact that this is in the archive, this is still really useful. TLS for App Developers forums post Choosing a Network Debugging Tool documentation WWDC 2019 Session 712 Advances in Networking, Part 1 — This explains the concept of constrained networking, which is Apple’s preferred solution to questions like How do I check whether I’m on Wi-Fi? TN3135 Low-level networking on watchOS TN3179 Understanding local network privacy Adapt to changing network conditions tech talk TCP and UDP ports used by Apple software products support article Understanding Also-Ran Connections forums post Extra-ordinary Networking forums post Foundation networking: Forums tags: Foundation, CFNetwork URL Loading System documentation — NSURLSession, or URLSession in Swift, is the recommended API for HTTP[S] on Apple platforms. Moving to Fewer, Larger Transfers forums post Testing Background Session Code forums post Network framework: Forums tag: Network Network framework documentation — Network framework is the recommended API for TCP, UDP, and QUIC on Apple platforms. Building a custom peer-to-peer protocol sample code (aka TicTacToe) Implementing netcat with Network Framework sample code (aka nwcat) Configuring a Wi-Fi accessory to join a network sample code Moving from Multipeer Connectivity to Network Framework forums post NWEndpoint History and Advice forums post Wi-Fi (general): How to modernize your captive network developer news post Wi-Fi Fundamentals forums post Filing a Wi-Fi Bug Report forums post Working with a Wi-Fi Accessory forums post — This is part of the Extra-ordinary Networking series. Wi-Fi (iOS): TN3111 iOS Wi-Fi API overview technote Wi-Fi Aware framework documentation WirelessInsights framework documentation iOS Network Signal Strength forums post Network Extension Resources Wi-Fi on macOS: Forums tag: Core WLAN Core WLAN framework documentation Secure networking: Forums tags: Security Apple Platform Security support document Preventing Insecure Network Connections documentation — This is all about App Transport Security (ATS). WWDC 2017 Session 701 Your Apps and Evolving Network Security Standards [1] — This is generally interesting, but the section starting at 17:40 is, AFAIK, the best information from Apple about how certificate revocation works on modern systems. WWDC 2025 Session 314 Get ahead with quantum-secure cryptography Available trusted root certificates for Apple operating systems support article Requirements for trusted certificates in iOS 13 and macOS 10.15 support article About upcoming limits on trusted certificates support article Apple’s Certificate Transparency policy support article What’s new for enterprise in iOS 18 support article — This discusses new key usage requirements. Prepare your network environment for stricter security requirements support article — This is primarily of interest to folks developing management software, for example, an MDM server. Technote 2232 HTTPS Server Trust Evaluation Technote 2326 Creating Certificates for TLS Testing QA1948 HTTPS and Test Servers Miscellaneous: More network-related forums tags: 5G, QUIC, Bonjour On FTP forums post Using the Multicast Networking Additional Capability forums post Investigating Network Latency Problems forums post Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" [1] This video is no longer available from Apple, but the URL should help you locate other sources of this info.

I've just implemented background session downloads, and in testing (with 1044 downloadTasks), I'm seeing some strange behavior that's not 100% reproducible. Sometimes when I background the app, when I foreground it (or the OS does), the URLSessionDownloadDelegate's function urlSession(_:downloadTask:didFinishDownloadingTo:) gets called twice. I'm also logging the URLSessionTaskDelegate's function urlSession(_:task:didCompleteWithError:) and in this case, it does not get called between calls to didFinishDownloadingTo. Both cases are being called with the exactly same task, session and location. The first call copies the location to a semi-permanent destination (and I confirmed that file is correct), and the second call fails on move because the destination already exists. I can obviously work around this fairly easily, but wondering if I'm missing something or if there's a bug. It does appear to happen more reliably when I background for 15 seconds or longer. A second issue which is reproducible is that while backgrounded, some files are completing downloads and never calling the download delegate's urlSession(_:downloadTask:didWriteData:totalBytesWritten:totalBytesExpectedToWrite:) I tried resuming one or all of the tasks in applicationDidBecomeActive as suggested in multiple other forums posts, but neither of those seems to resolve the issue. Again, I can work around this (using a combination of totalBytesWritten and the known size of files which have completed downloads), but I'm wondering if I'm missing something obvious. I actually thought that perhaps the resume() workaround was causing the first issue, but removing it does not have an effect.

I've been able to run this sample project with the PIRServer. But the urls are still not blocked. https://developer.apple.com/documentation/networkextension/filtering-traffic-by-url https://github.com/apple/pir-service-example I got this on the log Received filter status change: <FilterStatus: 'running'>

Dear Apple Developer Technical Support, I am currently developing a macOS network filtering solution using NetworkExtension with NEFilterDataProvider. During implementation of the handleOutboundData logic, we are using the following verdict: NEFilterNewFlowVerdict.filterDataVerdict( withFilterInbound: true, peekInboundBytes: InboundPeekBytes, filterOutbound: true, peekOutboundBytes: OutboundPeekBytes ) However, we have encountered an issue when SMB traffic is involved. When SMB protocol communication occurs, the network connection occasionally becomes unresponsive or appears to stall when peekOutboundBytes is set to a large value. Through testing, we observed the following behavior: On some systems, reducing the peekOutboundBytes value allows SMB communication to proceed normally. On other systems, even relatively small values can still cause the SMB connection to stall. This behavior appears inconsistent across different macOS environments. Because of this, we would like to clarify the following: Is there a documented or recommended maximum value for peekOutboundBytes when using NEFilterNewFlowVerdict.filterDataVerdict? Are there any internal limits or constraints within NetworkExtension that could cause SMB traffic to stall when the peek buffer size is too large? Are there best practices for selecting appropriate peekInboundBytes / peekOutboundBytes values when filtering high-throughput protocols such as SMB? If necessary, we can provide additional information such as macOS version, test environment details, and logs. Thank you for your assistance. Best regards, sangho

Have you ever encountered the issue where the Wi-Fi MAC address information can no longer be retrieved after I updated to iOS 26?

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.

Is Apple's Wi-Fi Aware certified by the Wi-Fi Alliance? Is there any non-compliance of Apple's Wi-Fi Aware with the Wi-Fi Alliance standards? Does Apple have a roadmap to switch AWDL to Wi-Fi Aware? Does Apple have plans to adopt Wi-Fi Aware in Mac computers?

Here’s the formatted summary in English for your issue submission: Issue Summary We are activating a Network Extension system extension (filter-data) from a signed and notarized macOS app. Activation consistently fails with the following error: Error Message: OSSystemExtensionErrorDomain code=4 Extension not found in App bundle. Unable to find any matched extension with identifier: com.seaskylight.yksmacos.ExamNetFilter.data At the same time, sysextd logs show: no policy, cannot allow apps outside /Applications However, our host app and executable paths are already under /Applications, and the extension bundle physically exists in the expected app bundle location. Environment Information macOS: Darwin 25.4.0 Host App: /Applications/xxx.app Host Bundle ID: com.seaskylight.yksmacos System Extension Bundle ID: com.seaskylight.yksmacos.ExamNetFilter.data Team ID: BVU65MZFLK Device Management: Enrolled via DEP: No MDM Enrollment: No Reproduction Steps Install the host app to /Applications. Launch the host app via Finder or using the command: open -a "/Applications/xxx.app" Trigger OSSystemExtensionRequest activationRequestForExtension for: com.seaskylight.yksmacos.ExamNetFilter.data. Observe failure callback (code=4). Collect logs: log show --last 2m --style compact --info --debug --predicate 'process == "sysextd"' Check extension status using: systemextensionsctl list (shows 0 extension(s)) Observed Results sysextd client activation request for com.seaskylight.yksmacos.ExamNetFilter.data attempts to realize extension with identifier com.seaskylight.yksmacos.ExamNetFilter.data. Log indicates: no policy, cannot allow apps outside /Applications App-side Diagnostics (captured at failure) PID: 3249 Bundle Path: /Applications/xxx.app Real Path: /Applications/xxx.app Exec Path: /Applications/xxx.app/Contents/MacOS/xxx Real Exec Path: /Applications/xxx.app/Contents/MacOS/xxx Ext Path: /Applications/xxx.app/Contents/Library/SystemExtensions/ExamNetFilterData.systemextension Ext Exists: true Running From Helper: false Error Callback: NSError{domain=OSSystemExtensionErrorDomain code=4 desc=Extension not found in App bundle...} Additional Validation We reproduced the same failure using a minimal native host app (SysExtProbe) in /Applications that only submits the activation request for the same extension identifier. It also fails with OSSystemExtensionErrorDomain code=4, indicating this is not specific to Electron app logic. Signing / Packaging Notes Host app and system extension are signed with the same Team ID (BVU65MZFLK). System extension bundle exists under: /Applications/xxx.app/Contents/Library/SystemExtensions/ExamNetFilterData.systemextension Extension Info.plist contains bundle id: com.seaskylight.yksmacos.ExamNetFilter.data Host app includes NSSystemExtensionUsageDescription. Questions for DTS In non-MDM personal-device scenarios, what exact conditions trigger sysextd to emit: no policy, cannot allow apps outside /Applications even when both bundlePath and realpath are in /Applications? Can code=4 (“Extension not found in App bundle”) be returned for policy/state reasons even when the extension bundle is present and the identifier matches? Are there known sysextd policy/cache states that cause this behavior, and what is the recommended recovery procedure? Feel free to copy and paste this summary for your submission. If you need any further modifications or assistance, let me know!

I am referencing: https://developer.apple.com/documentation/foundation/pausing-and-resuming-uploads Specifically: You can’t resume all uploads. The server must support the latest resumable upload protocol draft from the HTTP Working Group at the IETF. Also, uploads that use a background configuration handle resumption automatically, so manual resuming is only needed for non-background uploads. I have control over both the app and the server, and can't seem to get it to work automatically with a background url session. In other words, making multiple requests to get the offset then upload, easy but I am trying to leverage this background configuration resume OS magic. So anyone know what spec version does the server/client need to implement? The docs reference version 3, however the standard is now at like 11. Of course, I am trying out 3. Does anyone know how exactly this resume is implemented in iOS, and what exactly it takes care of? I assumed that I can just POST to a generic end point, say /files, then the OS receives a 104 Location, and saves that. If the upload is interrupted, when the OS resumes the upload, it has enough information to figure out how to resume from the exact offset, either by making a HEAD request to get the offset, or handle a 409. I am assuming it does this, as if it doesn't, the 'uploads that use a background configuration handle resumption automatically' is useless, if it just restarts from 0. Note, of course making individual POST/HEAD/PATCH requests manually works, but at that point I'm not really leveraging any OS auto-magic, and am just consuming an API that could really implement any spec. This won't work in the background, as the OS seems to disallow random HTTP requests when it wakes the app for URLSession background resumes. As of right now, I have it 'partially' working, insofar as the app does receive the 104 didReceiveInformationalResponse url delegate call, however it seems to then hang; it stops sending bytes, seemingly when the 104 is received. However, the request does not complete. In other words, it doesn't seem to receive a client timeout or otherwise indicate the request has finished. Right now, I am starting a single request, POSTing to a /files end point, i.e. I am not getting the location first, then PATCHing to that, as if I do that, the OS 'automatic' resuming fails with a 409, i.e. it doesn't seem to make a HEAD request and/or use the 409 offset correction then continue with the PATCH. Any idea what could be going on?

1、已经检查过手机的存储空间，还有一百多G的空间。app端进行网络接口情况的时候报错了，报错信息如下： Error : Error Domain=NSPOSIXErrorDomain Code=28 "No space left on device" UserInfo={_NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <7DB1CBFD-B9BE-422D-9C9A-78D8FC04DC1B>.<76>, _kCFStreamErrorDomainKey=1, _kCFStreamErrorCodeKey=28, _NSURLErrorRelatedURLSessionTaskErrorKey=( "LocalDataTask <7DB1CBFD-B9BE-422D-9C9A-78D8FC04DC1B>.<76>" ), _NSURLErrorNWPathKey=satisfied (Path is satisfied), interface: pdp_ip0[lte], ipv4, ipv6, dns, expensive, estimated upload: 65536Bps, uses cell} 2、手机型号是iPhone 15 Plus，iOS 17.6.1

Our application uses NEFilterPacketProvider to filter network traffic and we sometimes get a wired crash when removing/updating the network extension. It only happens on MacOS 11-12 . The crashing thread is always this one and it shows up after I call the completionHandler from the stopFilter func Application Specific Information: BUG IN CLIENT OF LIBDISPATCH: Release of a suspended object Thread 6 Crashed:: Dispatch queue: com.apple.network.connections 0 libdispatch.dylib 0x00007fff2039cc35 _dispatch_queue_xref_dispose.cold.1 + 24 1 libdispatch.dylib 0x00007fff20373808 _dispatch_queue_xref_dispose + 50 2 libdispatch.dylib 0x00007fff2036e2eb -[OS_dispatch_source _xref_dispose] + 17 3 libnetwork.dylib 0x00007fff242b5999 __nw_queue_context_create_source_block_invoke + 41 4 libdispatch.dylib 0x00007fff2036d623 _dispatch_call_block_and_release + 12 5 libdispatch.dylib 0x00007fff2036e806 _dispatch_client_callout + 8 6 libdispatch.dylib 0x00007fff203711b0 _dispatch_continuation_pop + 423 7 libdispatch.dylib 0x00007fff203811f4 _dispatch_source_invoke + 1181 8 libdispatch.dylib 0x00007fff20376318 _dispatch_workloop_invoke + 1784 9 libdispatch.dylib 0x00007fff2037ec0d _dispatch_workloop_worker_thread + 811 10 libsystem_pthread.dylib 0x00007fff2051545d _pthread_wqthread + 314 11 libsystem_pthread.dylib 0x00007fff2051442f start_wqthread + 15 I do have a DispatchSourceTimer but I cancel it in the stop func. Any ideas on how to tackle this?

Questions about FTP crop up from time-to-time here on DevForums. In most cases I write a general “don’t use FTP” response, but I don’t have time to go into all the details. I’ve created this post as a place to collect all of those details, so I can reference them in other threads. IMPORTANT Apple’s official position on FTP is: All our FTP APIs have been deprecated, and you should avoid using deprecated APIs. Apple has been slowly removing FTP support from the user-facing parts of our system. The most recent example of this is that we removed the ftp command-line tool in macOS 10.13. You should avoid the FTP protocol and look to adopt more modern alternatives. The rest of this post is an informational explanation of the overall FTP picture. This post is locked so I can keep it focused. If you have questions or comments, please do create a new thread in the App & System Services > Networking subtopic and I’ll respond there. Don’t Use FTP FTP is a very old and very crufty protocol. Certain things that seem obvious to us now — like being able to create a GUI client that reliably shows a directory listing in a platform-independent manner — aren’t possible to do in FTP. However, by far the biggest problem with FTP is that it provides no security [1]. Specifically, the FTP protocol: Provides no on-the-wire privacy, so anyone can see the data you transfer Provides no client-authenticates-server authentication, so you have no idea whether you’re talking to the right server Provides no data integrity, allowing an attacker to munge your data in transit Transfers user names and passwords in the clear Using FTP for anonymous downloads may be acceptable (see the explanation below) but most other uses of FTP are completely inappropriate for the modern Internet. IMPORTANT You should only use FTP for anonymous downloads if you have an independent way to check the integrity of the data you’ve downloaded. For example, if you’re downloading a software update, you could use code signing to check its integrity. If you don’t check the integrity of the data you’ve downloaded, an attacker could substitute a malicious download instead. This would be especially bad in, say, the software update case. These fundamental problems with the FTP protocol mean that it’s not a priority for Apple. This is reflected in the available APIs, which is the subject of the next section. FTP APIs Apple provides two FTP APIs: All Apple platforms provide FTP downloads via URLSession. Most Apple platforms (everything except watchOS) support CFFTPStream, which allows for directory listings, downloads, uploads, and directory creation. All of these FTP APIs are now deprecated: URLSession was deprecated for the purposes of FTP in the 2022 SDKs (macOS 13, iOS 16, iPadOS 16, tvOS 16, watchOS 9) [2]. CFFTPStream was deprecated in the 2016 SDKs (macOS 10.11, iOS 9, iPadOS 9, tvOS 9). CFFTPStream still works about as well as it ever did, which is not particularly well. Specifically: There is at least one known crashing bug (r. 35745763), albeit one that occurs quite infrequently. There are clear implementation limitations — like the fact that CFFTPCreateParsedResourceListing assumes a MacRoman text encoding (r. 7420589) — that won’t be fixed. If you’re looking for an example of how to use these APIs, check out SimpleFTPSample. Note This sample hasn’t been updated since 2013 and is unlikely to ever be updated given Apple’s position on FTP. The FTP support in URLSession has significant limitations: It only supports FTP downloads; there’s no support for uploads or any other FTP operations. It doesn’t support resumable FTP downloads [3]. It doesn’t work in background sessions. That prevents it from running FTP downloads in the background on iOS. It’s only supported in classic loading mode. See the usesClassicLoadingMode property and the doc comments in <Foundation/NSURLSession.h>. If Apple’s FTP APIs are insufficient for your needs, you’ll need to write or acquire your own FTP library. Before you do that, however, consider switching to an alternative protocol. After all, if you’re going to go to the trouble of importing a large FTP library into your code base, you might as well import a library for a better protocol. The next section discusses some options in this space. Alternative Protocols There are numerous better alternatives to FTP: HTTPS is by far the best alternative to FTP, offering good security, good APIs on Apple platforms, good server support, and good network compatibility. Implementing traditional FTP operations over HTTPS can be a bit tricky. One possible way forward is to enable DAV extensions on the server. FTPS is FTP over TLS (aka SSL). While FTPS adds security to the protocol, which is very important, it still inherits many of FTP’s other problems. Personally I try to avoid this protocol. SFTP is a file transfer protocol that’s completely unrelated to FTP. It runs over SSH, making it a great alternative in many of the ad hoc setups that traditionally use FTP. Apple doesn’t have an API for either FTPS or SFTP, although on macOS you may be able to make some headway by invoking the sftp command-line tool. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" [1] In another thread someone asked me about FTP’s other problems, those not related to security, so let’s talk about that. One of FTP’s implicit design goals was to provide cross-platform support that exposes the target platform. You can think of FTP as being kinda like telnet. When you telnet from Unix to VMS, it doesn’t aim to abstract away VMS commands, so that you can type Unix commands at the VMS prompt. Rather, you’re expected to run VMS commands. FTP is (a bit) like that. This choice made sense back when the FTP protocol was invented. Folks were expecting to use FTP via a command-line client, so there was a human in the loop. If they ran a command and it produced VMS-like output, that was fine because they knew that they were FTPing into a VMS machine. However, most users today are using GUI clients, and this design choice makes it very hard to create a general GUI client for FTP. Let’s consider the simple problem of getting the contents of a directory. When you send an FTP LIST command, the server would historically run the platform native directory list command and pipe the results back to you. To create a GUI client you have to parse that data to extract the file names. Doing that is a serious challenge. Indeed, just the first step, working out the text encoding, is a challenge. Many FTP servers use UTF-8, but some use ISO-Latin-1, some use other standard encodings, some use Windows code pages, and so on. I say “historically” above because there have been various efforts to standardise this stuff, both in the RFCs and in individual server implementations. However, if you’re building a general client you can’t rely on these efforts. After all, the reason why folks continue to use FTP is because of it widespread support. [2] To quote the macOS 13 Ventura Release Notes: FTP is deprecated for URLSession and related APIs. Please adopt modern secure networking protocols such as HTTPS. (92623659) [3] Although you can implement resumable downloads using the lower-level CFFTPStream API, courtesy of the kCFStreamPropertyFTPFileTransferOffset property. Revision History 2025-10-06 Explained that URLSession only supports FTP in classic loading mode. Made other minor editorial changes. 2024-04-15 Added a footnote about FTP’s other problems. Made other minor editorial changes. 2022-08-09 Noted that the FTP support in URLSession is now deprecated. Made other minor editorial changes. 2021-04-06 Fixed the formatting. Fixed some links. 2018-02-23 First posted.

Hi Team, I have a Network Extension application and UI frontend for it. The UI frontend talks to the Network Extension using XPC, as provided by NEMachServiceName. On M2 machine, The application and XPC connection works fine on clean installation. But, when the application is upgraded, the XPC connection keeps failing. Upgrade steps: PreInstall script kills the running processes, both UI and Network Extension Let installation continue PostInstall script to launch the application after installation complete. Following code is successful to the point of resume from UI application NSXPCInterface *exportedInterface = [NSXPCInterface interfaceWithProtocol:@protocol(IPCUIObject)]; newConnection.exportedInterface = exportedInterface; newConnection.exportedObject = delegate; NSXPCInterface *remoteObjectInterface = [NSXPCInterface interfaceWithProtocol:@protocol(IPCExtObject)]; newConnection.remoteObjectInterface = remoteObjectInterface; self.currentConnection = newConnection; [newConnection resume]; But it fails to get the object id<IPCExtObject> providerProxy = [self.currentConnection remoteObjectProxyWithErrorHandler:^(NSError *registerError) { }]; Please note, this only fails for M2. For M1, this exact code is running fine. Additionally, if I uninstall the application by dropping it in Trash and then installing the newer version, then too, the application works fine.

Hello, I have encountered an issue with an iPhone 15PM with iOS 18.5. The NSHTTPCookieStorage failed to clear cookies, after clearing them, I was still able to retrieve them. However, on the same system NSHTTPCookie *cookie; NSHTTPCookieStorage *storage = [NSHTTPCookieStorage sharedHTTPCookieStorage]; for (cookie in [storage cookies]) { [storage deleteCookie:cookie]; } NSArray *cookies = [[NSHTTPCookieStorage sharedHTTPCookieStorage] cookiesForURL:[[self url] absoluteURL]]; // still able to get cookies,why???

Our app is developed for iOS, but some users also run it on macOS (as an iOS app via Apple Silicon). The app requires local network permission, which works perfectly on iOS. Previously, the connection also worked fine on macOS, but since the recent macOS update, the app can no longer connect to our device. Additionally, our app on macOS doesn't prompt for local network permission at all, whereas it does on iOS. Is this a known issue with iOS apps running on macOS? Has anyone else experienced this problem, or is there a workaround? Any help would be appreciated!

cant open this website: https://appstoreconnect.apple.com/apps  Bad Gateway Correlation Key: EJMQBY3TQQI6QR2RBCFRFK7WSM

Hello everyone, I'm trying to figure out how to transmit a UIImage (png or tiff) securely to an application running in my desktop browser (Mac or PC). The desktop application and iOS app would potentially be running on the same local network (iOS hotspot or something) or have no internet connection at all. I'm trying to securely send over an image that the running desktop app could ingest. I was thinking something like a local server securely accepting image data from an iPhone. Any suggestions ideas or where to look for more info would be greatly appreciated! Thank you for your help.

I've seen a number of similar posts from other network system extension developers reporting kernel panics on M5 devices in macOS. These kernel panics occur when network system extensions are enabled and are not observed on earlier mac platforms or versions of macOS. Reference: https://developer.apple.com/forums/thread/821372 In this post, it appears like Apple is aware of a problem as noted by Kevin Elliott in versions of macOS. Do we know if there is any way to work around this problem (short of not enabling a network filter) until a fix is available?

Hello, I have encountered an issue with an iPhone 15PM with iOS 18.5. The NSHTTPCookieStorage failed to clear cookies, but even after clearing them, I was still able to retrieve them. However, on the same system It is normal on iPhone 14PM. I would like to know the specific reason and whether there are any adaptation related issues. Following code: NSHTTPCookie *cookie; NSHTTPCookieStorage *storage = [NSHTTPCookieStorage sharedHTTPCookieStorage]; for (cookie in [storage cookies]) { [storage deleteCookie:cookie]; }

This is a bit complicated to explain so bare with me. I am working on building an app that allows you to send real time video/camera captures from one Apple device to another. I am using a custom UDP protocol built on top of NWListener, NWBrowser, and NWConnection APIs. It works fine, but there are a few issues that seems to all be related to awdl: When transmitting via WiFi over the router (not using peer-to-peer), there are periodic interruptions when the wireless card on the device changes channels for awdl polling. This is resolved by changing the 5GHz WiFi channel on the router to channel 149 (or disabling AWDL altogether which is not really feasible). In order to work around number 1, I decided to build in an option to toggle/prefer peer-to-peer transmission in the app thinking that if everything goes over a peer-to-peer connection the jitter caused from the channel switching should go away. This also works, but with an important caveat. The default transmission is extremely choppy until you take an OS action that “elevates” the AWDL connection into “realtime” mode. I am using includePeerToPeer on the listener, browser, and connection as well as serviceClass interactiveVideo. For number 1, you can understand that asking users to change the channel on their router is not a great user experience, but the problem is the peer-to-peer connection workaround is also not great by default. For number 2, as an example of the behavior, I can send a stream from my Mac to my iPad over a peer-to-peer connection and it works but the video is very choppy until I move my cursor from my Mac to my iPad to trigger Universal Control. I captured the OS logs while doing this and can confirm that something happens to trigger “realtime” mode on the AWDL connection. After that, the streaming is totally smooth with zero latency. Some log samples: 2026-03-19 12:42:01.277968-0400 0x1ae294c Default 0x0 495 3 rapportd: (CoreUtils) [com.apple.rapport:CLinkD] Update client from UniversalControl:697 2026-03-19 12:42:01.278031-0400 0x1ae294c Default 0x0 495 0 rapportd: (CoreUtils) [com.apple.CoreUtils:AsyncCnx] CLinkCnx-6089: Connect start: 'CLink-ed3b9618b4e0._companion-link._tcp.local.%13' 2026-03-19 12:42:01.278149-0400 0x1ae294c Default 0x0 495 0 rapportd: (CoreUtils) [com.apple.CoreUtils:AsyncCnx] CLinkCnx-6089: Querying SRV CLink-ed3b9618b4e0._companion-link._tcp.local.%13 2026-03-19 12:42:01.279454-0400 0x1ae253a Info 0x0 382 0 wifip2pd: [com.apple.awdl:datapathInitiator] Created AWDLDatapathInitiator clink-ed3b9618b4e0._companion-link._tcp.local <To: 2e:f2:5a:15:76:52> 2026-03-19 12:42:01.279498-0400 0x1ae294c Default 0x0 495 0 rapportd: (CoreUtils) [com.apple.CoreUtils:AsyncCnx] CLinkCnx-6089: Resolving DNS f970afcc-1f1c-47af-a3f3-0236c9f9bbb0.local.%13 2026-03-19 12:42:01.279588-0400 0x1ae253a Default 0x0 382 0 wifip2pd: [com.apple.awdl:datapathInitiator] AWDLDatapathInitiator clink-ed3b9618b4e0._companion-link._tcp.local <To: 2e:f2:5a:15:76:52> was started 2026-03-19 12:42:01.282537-0400 0x1ae294c Default 0x0 495 0 rapportd: (Network) [com.apple.network:path] nw_path_evaluator_start [5C54D967-624D-4269-B080-6C7AE63218C7 IPv6#1e905043%awdl0.49154 generic, attribution: developer] path: satisfied (Path is satisfied), interface: awdl0[802.11], dns, uses wifi 2026-03-19 12:42:01.596450-0400 0x1ae253a Debug 0x0 382 0 wifip2pd: [com.apple.awdl:driver] Received event realtimeMode 2026-03-19 12:42:01.596589-0400 0x1ae253a Default 0x0 382 0 wifip2pd: [com.apple.awdl:interface] Realtime mode updated true I noticed that on iOS 26 and iPadOS 26 a realtime mode was added specifically to the Wi-Fi Aware API which I assume does what I want: https://developer.apple.com/documentation/wifiaware/waperformancemode/realtime, but I am looking for a solution that works with the existing network API and also on previous OS versions. I have already tried a lot of things, but is there any way to programmatically trigger “realtime” mode? For additional context, the goal here is to have extremely low latency that also works for gaming. The actual latency introduced in 1 is approximately 30-50ms around once a second… adding a buffer to the stream makes the video completely smooth, but the extra delay on the receiver end is not acceptable for this use case. Any help or ideas would be appreciated. I can’t easily share a reproduce case right now, and even if I could, getting multiple devices into the exact state along with the router configuration in order to reproduce is going to be pretty difficult anyway.

I'm trying to use ThreadNetwork API to manage TheradNetworks on device (following this documentation: https://developer.apple.com/documentation/threadnetwork/), but while some functions on THClient work (such as getPreferedNetwork), most don't (storeCredentials, retrieveAllCredentials). When calling these functions I get the following warning/error: Client: -[THClient getConnectionEntitlementValidity]_block_invoke - Error: -[THClient storeCredentialsForBorderAgent:activeOperationalDataSet:completion:]_block_invoke:701: - Error: Error Domain=NSCocoaErrorDomain Code=4099 "The connection to service with pid 414 named com.apple.ThreadNetwork.xpc was invalidated from this process." UserInfo={NSDebugDescription=The connection to service with pid 414 named com.apple.ThreadNetwork.xpc was invalidated from this process.} Error Domain=NSCocoaErrorDomain Code=4099 "The connection to service with pid 414 named com.apple.ThreadNetwork.xpc was invalidated from this process." UserInfo={NSDebugDescription=The connection to service with pid 414 named com.apple.ThreadNetwork.xpc was invalidated from this process.} Failed to store Thread credentials: Couldn’t communicate with a helper application. STEPS TO REPRODUCE Create new project Add Thread Network capability via Xcode UI (com.apple.developer.networking.manage-thread-network-credentials) Trigger storeCredentials let extendedMacData = "9483C451DC3E".hexadecimal let tlvHex = "0e080000000000010000000300001035060004001fffe002083c66f0dc9ef53f1c0708fdb360c72874da9905104094dce45388fd3d3426e992cbf0697b030d474c2d5332302d6e65773030310102250b04106c9f919a4da9b213764fc83f849381080c0402a0f7f8".hexadecimal // Initialize the THClient let thClient = THClient() // Store the credentials await thClient.storeCredentials(forBorderAgent: extendedMacData!, activeOperationalDataSet: tlvHex!) { error in if let error = error { print(error) print("Failed to store Thread credentials: \(error.localizedDescription)") } else { print("Successfully stored Thread credentials") } } NOTES: I tried with first calling getPreferedNetwork to initiate network permission dialog Tried adding meshcop to bojur services Tried with different release and debug build configurations