In our iOS application, we need to list available WiFi networks so that users can select one for device configuration. Here's the workflow: Initially, the hardware device acts as a WiFi Access Point (AP). The app should scan for nearby WiFi networks to detect the device's AP. The app connects temporarily to this AP and sends the selected WiFi credentials to the device. The device then connects to the selected WiFi network and stops broadcasting its AP. Is this flow achievable on iOS? We understand that Apple restricts access to WiFi scanning APIs — are there any supported methods (e.g., using NEHotspotHelper) or entitlements (such as MFi) that could enable this?

Hello, im currently developing proxy app with XrayCore trying to bypass APNs when tunnel us up and i found .excludeAPNs property in NETunnelProviderProtocol that works only when includeAllNetworks property is also TRUE. I wonder if there is a possible way to make APNs bypass tunnel in split tunnelling mode? because we use excludedRoutes and full tunnel is not an option

Before iOS16, we can use https://developer.apple.com/documentation/coretelephony/ctcarrier But after iOS this is deprecated and has no replacement. There are some discussions on it, eg. https://developer.apple.com/forums/thread/714876 https://developer.apple.com/forums/thread/770400 Now I asked AI, then it provided this solution, to check the serviceCurrentRadioAccessTechnology, so it this ok to check the SIM card status? var hasSIMCard = false let info = CTTelephonyNetworkInfo() if let rat = info.serviceCurrentRadioAccessTechnology, rat.values.contains(where: { !$0.isEmpty }) { hasSIMCard = true. // has RAT } BTW, I can see a lot of changes in the Core Telephony framework. https://developer.apple.com/documentation/coretelephony 1.isSIMInserted https://developer.apple.com/documentation/coretelephony/ctsubscriber/issiminserted A Boolean property that indicates whether a SIM is present. iOS 18.0+ iPadOS 18.0+ This value property is true if the system finds a SIM matching the Info.plist carrier information (MCC / MNC / GID1 / GID2). Is this ok to check SIM insert status, this seems must preconfig some info in the info.plist. 2.iOS26 provide CTCellularPlanStatus https://developer.apple.com/documentation/coretelephony/ctcellularplanstatus Can I use this to check SIM status?

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.

Description: I'm noticing that when using the completion handler variant of URLSession.dataTask(with:), the delegate method urlSession(_:dataTask:didReceive:) is not called—even though a delegate is set when creating the session. Here's a minimal reproducible example: ✅ Case where delegate method is called: class CustomSessionDelegate: NSObject, URLSessionDataDelegate { func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) { print("✅ Delegate method called: Data received") } } let delegate = CustomSessionDelegate() let session = URLSession(configuration: .default, delegate: delegate, delegateQueue: nil) let request = URLRequest(url: URL(string: "https://httpbin.org/get")!) let task = session.dataTask(with: request) // ✅ No completion handler task.resume() In this case, the delegate method didReceive is called as expected. ❌ Case where delegate method is NOT called: class CustomSessionDelegate: NSObject, URLSessionDataDelegate { func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) { print("❌ Delegate method NOT called") } } let delegate = CustomSessionDelegate() let session = URLSession(configuration: .default, delegate: delegate, delegateQueue: nil) let request = URLRequest(url: URL(string: "https://httpbin.org/get")!) let task = session.dataTask(with: request) { data, response, error in print("Completion handler called") } task.resume() Here, the completion handler is executed, but the delegate method didReceive is never called. Notes: I’ve verified this behavior on iOS 16, 17, and 18. Other delegate methods such as urlSession(_:task:didFinishCollecting:) do get called with the completion handler API. This happens regardless of whether swizzling or instrumentation is involved — the issue is reproducible even with direct method implementations. Questions: Is this the expected behavior (i.e., delegate methods like didReceive are skipped when a completion handler is used)? If yes, is there any official documentation that explains this? Is there a recommended way to ensure delegate methods are invoked, even when using completion handler APIs? Thanks in advance!

In our project, we download H5 resources to the local device and then open the H5 pages through WKWebView(-loadFileURL:allowingReadAccessToURL:). When the H5 pages request server resources, cookies are required. Before opening the H5 page, we set the required cookies in the WKHTTPCookieStore using the setCookie method. Additionally, we set the allowFileAccessFromFileURLs and allowUniversalAccessFromFileURLs properties for the WebView. On other mobile phones, the cookies can be carried normally. However, on mobile phones running the iOS 18.0 system, the cookies cannot be carried. Moreover, this problem only emerged after we upgraded Xcode to version 16.2. We've also tried injecting cookies via JavaScript, but it didn't work(document.cookie = xx=${xx}; path=/; expires=weekday, xx jan xxxx xx:xx:xx GMT; Domain=example.com; Secure; SameSite=None ;). Can anyone help me on this? Thanks in advance.

Hi everyone, I'm building a health-focused iOS and watchOS app that uses WatchConnectivity to sync real-time heart rate and core body temperature data from iPhone to Apple Watch. While the HealthKit integration works correctly on the iPhone side, I'm facing persistent issues with WatchConnectivity — the data either doesn't arrive on the Watch, or session(_:didReceiveMessage:) never gets triggered. Here's the setup: On iPhone: Using WCSession.default.sendMessage(_:replyHandler:errorHandler:) to send real-time values every few seconds. On Apple Watch: Implemented WCSessionDelegate, and session(_:didReceiveMessage:) is supposed to update the UI. Both apps have WCSession.isSupported() checks, activate the session, and assign delegates correctly. The session state shows isPaired = true and isWatchAppInstalled = true. Bluetooth and Wi-Fi are on, both devices are unlocked and nearby. Despite all this, the Watch never receives messages in real-time. Sometimes, data comes through in bulk much later or not at all. I've double-checked Info.plist configurations and made sure background modes include "Uses Bluetooth LE accessories" and "Background fetch" where appropriate. I would really appreciate guidance on: Best practices for reliable, low-latency message delivery with WatchConnectivity. Debugging steps or sample code to validate message transmission and reception. Any pitfalls related to UI updates from the delegate method. Happy to share further details. Thanks in advance!

Starting on macOS Sequoia, flows originated in Firefox have an empty sourceAppAuditToken. Other apps contain a valid token. Background: in order to fetch process info for a certain NEFilterFlow, my content filter extension uses sourceAppAuditToken, audit_token_to_pid() and proc_* (as recommended in #126820). When that fails, we use SecCodeCopyGuestWithAttributes, recommended in some other thread as a better alternative. Both approaches break when the sourceAppAuditToken is empty since they need the pid. Debugging: My logging shows audit token is empty for Firefox Typical logs from com.apple.networkextension also indicate it fails to fetch the same info I'm looking for: com.apple.networkextension debug 11:22:07.024588-0300 Fetching appInfo from cache for pid: 948 uuid: 5C40B765-C6C9-3641-A822-2BC44D264361 bundle id: (null) com.apple.networkextension debug 11:22:07.024657-0300 Calling delegate lookup handler with pid: 948, uuid: 5C40B765-C6C9-3641-A822-2BC44D264361, bundleID: (null) com.apple.networkextension debug 11:22:07.025856-0300 Could not look up appInfo for pid: 948 bundle id: (null) uuid: 5C40B765-C6C9-3641-A822-2BC44D264361 com.apple.networkextension error 11:22:07.025897-0300 Could not find app info, return the original flow without filling in app info Handling new flow: identifier = D89B5B5D-793C-4940-D992-4E90F2AD1900 procPID = 953 eprocPID = 948 direction = outbound inBytes = 0 outBytes = 0 signature = {length = 32, bytes = 0x4afeafde b484aa0c c5cb8698 0567343d ... 7cdee33e 135666dd } socketID = 19adf2904e92d9 localEndpoint = 0.0.0.0:0 remoteEndpoint = 17.33.202.170:443 protocol = 6 family = 2 type = 1 procUUID = 0C68E603-967E-3643-B225-378BD2A655F7 eprocUUID = 5C40B765-C6C9-3641-A822-2BC44D264361 Perhaps there's a bug when generating the audit token or could it be something with the Firefox signature? I double-checked Firefox and it seems fine: $ codesign --verify --verbose /Applications/Firefox.app /Applications/Firefox.app: valid on disk /Applications/Firefox.app: satisfies its Designated Requirement Not sure if relevant, but codesign with -dv showed different flags in CodeDirectory when compared to chrome: codesign -dv /Applications/Firefox.app ... CodeDirectory v=20500 size=863 flags=0x10000(runtime) hashes=18+5 ... Versus chrome CodeDirectory v=20500 size=1821 flags=0x12a00(kill,restrict,library-validation,runtime) hashes=46+7 location=embedded

We have an iPad application that utilizes Multipeer Connectivity to enable local communication between devices running a copy of our app. Until recently, we were able to test this functionality in the Xcode simulator without any issues. We could easily set up multiple simulators and have them all communicate with each other. However, recently, either due to an upgrade to Xcode or MacOS, this functionality ceased working in the simulator. Surprisingly, it still functions perfectly on physical devices. If we reboot the development computer and launch the simulator immediately after the reboot (without building and sending from Xcode, but running the existing code on the device), the issue resolves. However, the moment we generate a new build and send it to the simulator from Xcode, the multipeer functionality stops working again in the simulator. The simulators won’t reconnect until a reboot of the physical Mac hardware hosting the simulator. We’ve tried the usual troubleshooting steps, such as downgrading Xcode, deleting simulators and recreating them, cleaning the build folder, and deleting derived data, but unfortunately, none of these solutions have worked. The next step is to attempt to use a previous version of MacOS (15.3) and see if that helps, but I’d prefer to avoid this if possible. Does anyone have any obvious suggestions or troubleshooting steps that might help us identify the cause of this issue?

We are developing a desktop app for macOS, built with Electron + Angular + Node.js. The app has the ability to access devices on the local network. We are having some trouble with the behavior of the "Local Network" feature added in macOS 15. Procedure: MacBook Pro 14inch (M1Pro) 2021, 16GB memory - macOS Sequoia15.4.1 Network Environment: The PC and the access point are connected by wire, and the target device and the access point are also connected by wire. Not connected to an external network Install the target app Start the application and allow the "Local Network" dialog that appears Open the "Local Network" item in "Privacy and Security" and make sure the target app is allowed. Confirm that you can access the target device on the local network Restart the PC Open the "Local Network" item in "Privacy and Security" and make sure the target app is allowed. Start the app and access the target device on the local network Result: Access to the target device may fail (this does not occur 100% of the time) If you turn the target app in the "Local Network" section of "Privacy and Security" OFF and then ON, you will be able to connect However, it seems that the problem may occur again if you restart your PC. According to our research, the probability of this happening increases if the target app is the only app allowed on the "local network". This happens not only with our app, but also when you follow the above steps in "Google Chrome". Based on the above investigation results, I suspect that this is a problem with the OS. What do you think?

Hello Everyone, I am currently using macOS 15.5 and XCode 16.4. I am using the following code to send/receive multicast packets on multicast group ff02::1 and port 49153 using Apple NF's NWConnectionGroup. import Network import Foundation // Creating a mutlicast group endpoint let multicastIPv6GroupEndpoint: NWEndpoint = NWEndpoint.hostPort(host: NWEndpoint.Host.ipv6(IPv6Address("ff02::1")!), port: NWEndpoint.Port("49153")!) do { let multicastGroupDescriptor: NWMulticastGroup = try NWMulticastGroup (for: [multicastIPv6GroupEndpoint]) let multicastConnectionGroupDescriptor = NWConnectionGroup (with: multicastGroupDescriptor, using: .udp) multicastConnectionGroupDescriptor.stateUpdateHandler = { state in print ("🕰️ Connection Group state: \(state)") if state == .ready { multicastConnectionGroupDescriptor.send (content: "👋🏻 Hello from the Mac 💻".data (using: .utf8)) { err in print ("➡️ Now, I am trying to send some messages.") if let err = err { print ("💥 Error sending multicast message: \(err)") } else { print ("🌚 Initial multicast message sent") } } } } multicastConnectionGroupDescriptor.setReceiveHandler { message, content, isComplete in if let content = content, let messageString = String (data: content, encoding: .utf8) { print ("⬅️ Received message: \(messageString)") } } multicastConnectionGroupDescriptor.start (queue: .global()) } catch { print ("💥 Error while creating Multicast Group: \(error)") } RunLoop.main.run() I am able to successfully create a NWConnectionGroup without any warnings/errors. The issue occurs when the stateUpdateHandler's callback gets invoked. It first gives me this warning: nw_listener_socket_inbox_create_socket IPV6_LEAVE_GROUP ff02::1.49153 failed [49: Can't assign requested address But then it shows me that the state is ready: 🕰️ Connection Group state: ready After this, when the send is performed, it gives me a bunch of errros: nw_endpoint_flow_failed_with_error [C1 ff02::1.49153 waiting parent-flow (unsatisfied (Local network prohibited), interface: en0[802.11], ipv4, ipv6, uses wifi)] already failing, returning nw_socket_connect [C1:1] connectx(7, [srcif=0, srcaddr=::.62838, dstaddr=ff02::1.49153], SAE_ASSOCID_ANY, 0, NULL, 0, NULL, SAE_CONNID_ANY) failed: [48: Address already in use] nw_socket_connect [C1:1] connectx failed (fd 7) [48: Address already in use] nw_socket_connect connectx failed [48: Address already in use] nw_endpoint_flow_failed_with_error [C1 ff02::1.49153 in_progress socket-flow (satisfied (Path is satisfied), interface: en0[802.11], ipv4, ipv6, dns, uses wifi)] already failing, returning There is no other background process running on the same port. I tried using different ports as well as multicast groups but the same error persists. The same code works fine for an IPv4 multicast group. I have following questions: Why am I getting these errors specifically for IPv6 multicast group but not for IPv4 multicast group? Are there any configurations that needed to be done in order to get this working?

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.

I implemented a Network Extension in the macOS, use NETransparentProxyProvider. After installing and enabling it, I implemented a UDP client to test its. I found that the UDP client failed to send the data successfully (via sendto, and it returned a success), and when using Wireshark to capture the network data packet, I still couldn't see this UDP data packet. The code for Network Extension is like this: @interface MyTransparentProxyProvider : NETransparentProxyProvider @end @implementation MyTransparentProxyProvider - (void)startProxyWithOptions:(NSDictionary *)options completionHandler:(void (^)(NSError *))completionHandler { NETransparentProxyNetworkSettings *objSettings = [[NETransparentProxyNetworkSettings alloc] initWithTunnelRemoteAddress:@"127.0.0.1"]; // included rules NENetworkRule *objIncludedNetworkRule = [[NENetworkRule alloc] initWithRemoteNetwork:nil remotePrefix:0 localNetwork:nil localPrefix:0 protocol:NENetworkRuleProtocolAny direction:NETrafficDirectionOutbound]; NSMutableArray<NENetworkRule *> *arrIncludedNetworkRules = [NSMutableArray array]; [arrIncludedNetworkRules addObject:objIncludedNetworkRule]; objSettings.includedNetworkRules = arrIncludedNetworkRules; // apply [self setTunnelNetworkSettings:objSettings completionHandler: ^(NSError * _Nullable error) { // TODO } ]; if (completionHandler != nil) completionHandler(nil); } - (BOOL)handleNewFlow:(NEAppProxyFlow *)flow { if (flow == nil) return NO; char szProcPath[PROC_PIDPATHINFO_MAXSIZE] = {0}; audit_token_t *lpAuditToken = (audit_token_t*)flow.metaData.sourceAppAuditToken.bytes; if (lpAuditToken != NULL) { proc_pidpath_audittoken(lpAuditToken, szProcPath, sizeof(szProcPath)); } if ([flow isKindOfClass:[NEAppProxyTCPFlow class]]) { NWHostEndpoint *objRemoteEndpoint = (NWHostEndpoint *)((NEAppProxyTCPFlow *)flow).remoteEndpoint; LOG("-MyTransparentProxyProvider handleNewFlow:] TCP flow! Process: (%d)%s, %s Remote: %s:%s, %s", lpAuditToken != NULL ? audit_token_to_pid(*lpAuditToken) : -1, flow.metaData.sourceAppSigningIdentifier != nil ? [flow.metaData.sourceAppSigningIdentifier UTF8String] : "", szProcPath, objRemoteEndpoint != nil ? (objRemoteEndpoint.hostname != nil ? [objRemoteEndpoint.hostname UTF8String] : "") : "", objRemoteEndpoint != nil ? (objRemoteEndpoint.port != nil ? [objRemoteEndpoint.port UTF8String] : "") : "", ((NEAppProxyTCPFlow *)flow).remoteHostname != nil ? [((NEAppProxyTCPFlow *)flow).remoteHostname UTF8String] : "" ); } else if ([flow isKindOfClass:[NEAppProxyUDPFlow class]]) { NSString *strLocalEndpoint = [NSString stringWithFormat:@"%@", ((NEAppProxyUDPFlow *)flow).localEndpoint]; LOG("-[MyTransparentProxyProvider handleNewFlow:] UDP flow! Process: (%d)%s, %s LocalEndpoint: %s", lpAuditToken != NULL ? audit_token_to_pid(*lpAuditToken) : -1, flow.metaData.sourceAppSigningIdentifier != nil ? [flow.metaData.sourceAppSigningIdentifier UTF8String] : "", szProcPath, strLocalEndpoint != nil ? [strLocalEndpoint UTF8String] : "" ); } else { LOG("-[MyTransparentProxyProvider handleNewFlow:] Unknown flow! Process: (%d)%s, %s", lpAuditToken != NULL ? audit_token_to_pid(*lpAuditToken) : -1, flow.metaData.sourceAppSigningIdentifier != nil ? [flow.metaData.sourceAppSigningIdentifier UTF8String] : "", szProcPath ); } return NO; } @end The following methods can all enable UDP data packets to be successfully sent to the UDP server: 1.In -[MyTransparentProxyProvider startProxyWithOptions:completionHandler:], add the exclusion rule "The IP and port of the UDP server, the protocol is UDP"; 2.In -[MyTransparentProxyProvider startProxyWithOptions:completionHandler:], add the exclusion rule "All IPs and ports, protocol is UDP"; 3.In -[MyTransparentProxyProvider handleNewFlow:] or -[MyTransparentProxyProvider handleNewUDPFlow:initialRemoteEndpoint:], process the UDP Flow and return YES. Did I do anything wrong?

I'm using NERelayManager to set Relay configuration which all works perfectly fine. I then do a curl with the included domain and while I see QUIC connection succeeds with relay server and H3 request goes to the server, the connection gets abruptly closed by the client with "Software caused connection abort". Console has this information: default 09:43:04.459517-0700 curl nw_flow_connected [C1.1.1 192.168.4.197:4433 in_progress socket-flow (satisfied (Path is satisfied), viable, interface: en0[802.11], ipv4, ipv6, dns, uses wifi)] Transport protocol connected (quic) default 09:43:04.459901-0700 curl [C1.1.1 192.168.4.197:4433 in_progress socket-flow (satisfied (Path is satisfied), viable, interface: en0[802.11], ipv4, ipv6, dns, uses wifi)] event: flow:finish_transport @0.131s default 09:43:04.460745-0700 curl nw_flow_connected [C1.1.1 192.168.4.197:4433 in_progress socket-flow (satisfied (Path is satisfied), viable, interface: en0[802.11], ipv4, ipv6, dns, uses wifi)] Joined protocol connected (http3) default 09:43:04.461049-0700 curl [C1.1.1 192.168.4.197:4433 in_progress socket-flow (satisfied (Path is satisfied), viable, interface: en0[802.11], ipv4, ipv6, dns, uses wifi)] event: flow:finish_transport @0.133s default 09:43:04.465115-0700 curl [C2 E47A3A0C-7275-4F6B-AEDF-59077ABAE34B 192.168.4.197:4433 quic, multipath service: 1, tls, definite, attribution: developer] cancel default 09:43:04.465238-0700 curl [C2 E47A3A0C-7275-4F6B-AEDF-59077ABAE34B 192.168.4.197:4433 quic, multipath service: 1, tls, definite, attribution: developer] cancelled [C2 FCB1CFD1-4BF9-4E37-810E-81265D141087 192.168.4.139:53898<->192.168.4.197:4433] Connected Path: satisfied (Path is satisfied), viable, interface: en0[802.11], ipv4, ipv6, dns, uses wifi Duration: 0.121s, QUIC @0.000s took 0.000s, TLS 1.3 took 0.111s bytes in/out: 2880/4322, packets in/out: 4/8, rtt: 0.074s, retransmitted bytes: 0, out-of-order bytes: 0 ecn packets sent/acked/marked/lost: 3/1/0/0 default 09:43:04.465975-0700 curl nw_flow_disconnected [C2 192.168.4.197:4433 cancelled multipath-socket-flow ((null))] Output protocol disconnected default 09:43:04.469189-0700 curl nw_endpoint_proxy_receive_report [C1.1 IPv4#124bdc4d:80 in_progress proxy (satisfied (Path is satisfied), interface: en0[802.11], ipv4, ipv6, dns, proxy, uses wifi)] Privacy proxy failed with error 53 ([C1.1.1] masque Proxy: http://192.168.4.197:4433) default 09:43:04.469289-0700 curl [C1.1.1 192.168.4.197:4433 failed socket-flow (satisfied (Path is satisfied), viable, interface: en0[802.11], ipv4, ipv6, dns, uses wifi)] event: flow:failed_connect @0.141s, error Software caused connection abort Relay server otherwise works fine with our QUIC MASQUE clients but not with built-in macOS MASQUE client. Anything I'm missing?

I'm using Network framework for communication between devices. The first time I instantiate an NWBrowser, it will prompt the user with a popup that says: Allow &lt;app name&gt; to find devices on local networks? The problem is, once I upgraded from Xcode 15.4 to Xcode 16.4, the popup doesn't appear; it says in the debug window: nw_browser_fail_on_dns_error_locked [B1] nw_browser_dns_service_browse_callback failed: PolicyDenied(18,446,744,073,709,486,046) I do have the info.plist keys Privacy-Local Network Usage Description (NSLocalNetworkUsageDescription) and Bonjour Services (NSBonjourServices) so it's not that. Also, It still works on a real device. I think something changed with Xcode 16 that tightened the security on a simulator, or maybe disabled Network framework entirely. It's not the firewall on my computer because that is turned off. I'm using an M1 MacBook Pro.

My application needs local network access. When it is started for the first time, the user gets a prompt to enable local network access (as expected). The application is then shown as enabled in Privacy & Security / Local Network and local network access is working. If macOS is then shutdown and restarted, local network access is blocked for the application even though it is still shown as enabled in Privacy & Security / Local Network. Local network access can be restored either by toggling permission off and on in Privacy & Security / Local Network or by disabling and enabling Wi-Fi. This behaviour is consistent on Sequoia 15.1. It happens sometimes on 15.0 and 15.0.1 but not every time. Is my application doing something wrong or is this a Sequoia issue? If it is a Sequoia issue, is there some change I can make to my application to work around it?

Hi guys, I try to create a content filter app by using network extension api. When it comes to a https/tls remote endpoint, the remoteEndpoint.hostname will always be "" instead of the actual hostname. How can I extract the actual hostname? private func filterTraffic(flow: NEFilterSocketFlow) -> NEFilterNewFlowVerdict { // Default action from settings will be used if no rules match logger.error("filter traffic...") guard let remoteEndpoint = flow.remoteEndpoint as? NWHostEndpoint else { logger.error("not a NWHostEndpoint)") return .allow() } logger.error("host name: \(remoteEndpoint.hostname)") if remoteEndpoint.hostname.hasSuffix("google.com"){ logger.error("google.com") return .drop() } return .allow() } code-block

Hi! I've noticed that the IP_RECVIF socket option, i.e.: int y = 1; setsockopt(fd, IPPROTO_IP, IP_RECVIF, &y, sizeof(y)); does not seem to work if the socket is proxied by a NETransparentProxyProvider type network extension: there's no ancillary data in messages received with recvmsg. As soon as I disable the network extension, recvmsg starts returning ancillary data containing the interface name. This seems to break some applications which rely on IP_RECVIF in the presence of a transparent proxy, making it, in fact, not transparent. One such example is Apple's own libresolv, which relies on IP_RECVIF and breaks if there's no ancillary data in the recvmsg result. I don't think that this is the intended behaviour, since IPV6_PKTINFO seems to work fine. I've filed a bug report (FB17586550) about this, however, I would greatly appreciate if someone could point me in the direction of a workaround.

Hello! I develop transparent proxy based application, and I'm receiving a lot of crash reports from macOS 15.5 for crash in __88-[NEExtensionAppProxyProviderContext setInitialFlowDivertControlSocket:extraValidation:]_block_invoke.90 when stopping. Even very old versions of my software started crashing on macOS 15.5. I checked my extension that it correctly calls setTunnelNetworkSettings:nil on proxy stop, but crash is still here. Does anybody else have this problem? Do you know any workaround for it?

From time to time the subject of NECP grows up, both here on DevForums and in DTS cases. I’ve posted about this before but I wanted to collect those tidbits into single coherent post. If you have questions or comments, start a new thread in the App & System Services > Networking subtopic and tag it with Network Extension. That way I’ll be sure to see it go by. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" A Peek Behind the NECP Curtain NECP stands for Network Extension Control Protocol. It’s a subsystem within the Apple networking stack that controls which programs have access to which network interfaces. It’s vitally important to the Network Extension subsystem, hence the name, but it’s used in many different places. Indeed, a very familiar example of its use is the Settings > Mobile Data [1] user interface on iOS. NECP has no explicit API, although there are APIs that are offer some insight into its state. Continuing the Settings > Mobile Data example above, there is a little-known API, CTCellularData in the Core Telephony framework, that returns whether your app has access to WWAN. Despite having no API, NECP is still relevant to developers. The Settings > Mobile Data example is one place where it affects app developers but it’s most important for Network Extension (NE) developers. A key use case for NECP is to prevent VPN loops. When starting an NE provider, the system configures the NECP policy for the NE provider’s process to prevent it from using a VPN interface. This means that you can safely open a network connection inside your VPN provider without having to worry about its traffic being accidentally routed back to you. This is why, for example, an NE packet tunnel provider can use any networking API it wants, including BSD Sockets, to run its connection without fear of creating a VPN loop [1]. One place that NECP shows up regularly is the system log. Next time you see a system log entry like this: type: debug time: 15:02:54.817903+0000 process: Mail subsystem: com.apple.network category: connection message: nw_protocol_socket_set_necp_attributes [C723.1.1:1] setsockopt 39 SO_NECP_ATTRIBUTES … you’ll at least know what the necp means (-: Finally, a lot of NECP infrastructure is in the Darwin open source. As with all things in Darwin, it’s fine to poke around and see how your favourite feature works, but do not incorporate any information you find into your product. Stuff you uncover by looking in Darwin is not considered API. [1] Settings > Cellular Data if you speak American (-: [2] Network Extension providers can call the createTCPConnection(to:enableTLS:tlsParameters:delegate:) method to create an NWTCPConnection [3] that doesn’t run through the tunnel. You can use that if it’s convenient but you don’t need to use it. [3] NWTCPConnection is now deprecated, but there are non-deprecated equivalents. For the full story, see NWEndpoint History and Advice. Revision History 2025-12-12 Replaced “macOS networking stack” with “Apple networking stack” to avoid giving the impression that this is all about macOS. Added a link to NWEndpoint History and Advice. Made other minor editorial changes. 2023-02-27 First posted.