Hi! I'm working on a solution (iOS 18) that uses Network Extensions PacketTunnelProvider and Content Filter. Currently I'm trying to integrate it with another extension – DNSProxyProvider. My goal is to process dns queries and use resolved ips and names for additional routing inside of the packet tunnel. I'm running into a major issue: whenever both VPN and DNS proxy are active simultaneously, the device completely loses internet connectivity — no traffic goes through, and DNS resolution seems to stop working entirely. I know about the mdm supervision requirement to use DNSProxyProvider and that's covered as I work with a managed device and install a DNS proxy profile, here's how its .mobileconfig file looks like: The DNS proxy itself works fine when working by itself (without VPN being turned on), as I implemented it that it successfully processes DNS packets flows while collecting information about domains etc, and everything works perfectly. Problems begin when using VPN at the same time. I'm aware that tunnel settings include dns related options that can affect this, but I haven't had much luck with tweaking them. Here's how they look right now for reference: let settings: NEPacketTunnelNetworkSettings = NEPacketTunnelNetworkSettings(tunnelRemoteAddress: "240.0.0.1") // let dnsSettings = NEDNSSettings(servers: "8.8.8.8,8.8.4.4".components(separatedBy: ",")) // dnsSettings.matchDomains = [""] // settings.dnsSettings = dnsSettings settings.proxySettings = nil /* ipv4 settings */ let ipv4Settings = NEIPv4Settings(addresses: ["240.0.0.2"], subnetMasks: ["255.255.255.0"]) ipv4Settings.includedRoutes = [NEIPv4Route.default()] settings.ipv4Settings = ipv4Settings /* MTU */ settings.mtu = 1500 return settings I've tried excluding some dns related ip routes and dns settings shenanigans but nothing. I haven't found any information that might suggest that using both of these extensions at the same time doesn't work, on the contrary, this page in the official documentation about the expected use of packet tunnel provider the expected use of packet tunnel provider, as it talks about the fact that you should not use it for interception of all of DNS traffic, as the use of DNSPRoxyProvider (or dns settings) are built for that, which in my mind, suggests that there should be no problem with using them both and just splitting the dns traffic handling to the proxy. Will be thankful for any help!

I'm a long-time developer, but pretty new to Swift. I'm trying to get information from a web service (and found code online that I adjusted to build the function below). (Note: AAA_Result -- referenced towards the end -- is another class in my project) Trouble is, I'm getting the subject error on the call to session.dataTask. Any help/suggestions/doc pointers will be greatly appreciated!!! var result: Bool = false var cancellable: AnyCancellable? self.name = name let params = "json={\"\"}}" // removed json details let base_url = URL(string: "https://aaa.yyy.com?params=\(params)&format=json")! // removed URL specifics do { let task = URLSession.shared.dataTask(with: base_url) { data, response, error in if let error = error { print("Error: \(error)") } guard let response = response as? HTTPURLResponse, (200...299).contains(response.statusCode) else { print("Error \(String(describing: response))") } do { let decoder = JSONDecoder() let ar = try decoder.decode(AAA_Result.self, from: response.value) // removed specific details... result = true } catch { print(error) } } task.resume() } catch { print(error) } return result }

I'm developing a Matter-over-thread generic switch with 2 generic switch endpoints. This is configured as an Intermittently Connected Device with Long Idle Time. I have an Apple TV serving as the thread border router. I'm able to commission the device successfully in the Home app and assign actions to each of the buttons however when the device is rebooted the subscription doesn't appear to resume successfully and the buttons no longer work. I've tested this on various SOC's with their respective SDKs including ESP32-C6, nrf52840 and EFR32MG24 and the behaviour was consistent across all of them. It was working originally when I first started out on the ESP32-C6, then the issue popped up first when I was testing the nrf52840. In that SDK I set persistent subscriptions explicitly and it seemed to resolve the issue until it popped up again when I found that unplugging and restarting the Apple TV completely which appeared to fix the issue with subscriptions not resuming. Recently I've added a Home Pod Mini Gen 2 to the matter fabric so there are now two TBR on the network and restarting both the Apple TV and the HomePod doesn't appear to resolve the issue anymore and the subscriptions are not resuming across all three SOC's on device reboot I'm wondering if there might be something preventing the subscriptions from resuming?

I have granted local network permissions, but sometimes I get a second confirmation popup, what is the timing of the secondary popup?

Hi everyone, I'm currently experimenting with building a simple DNS filter using Apple's Packet Tunnel framework. Here's the flow I'm trying to implement: Create a TUN interface Set up a UDP socket Read packets via packetFlow.readPackets Parse the raw IP packet Forward the UDP payload through the socket Receive the response from the server Reconstruct the IP packet with the response Write it back to the TUN interface using packetFlow.writePackets Here’s an example of an intercepted IP packet (DNS request): 45 00 00 3c 15 c4 00 00 40 11 93 d1 c0 a8 00 64 08 08 08 08 ed 6e 00 35 00 28 e5 c9 7f da 01 00 00 01 00 00 00 00 00 00 04 74 69 6d 65 05 61 70 70 6c 65 03 63 6f 6d 00 00 01 00 01 And here’s the IP packet I tried writing back into the TUN interface (DNS response): 45 00 00 89 5e 37 40 00 40 11 0b 11 08 08 08 08 c0 a8 00 64 00 35 ed 6e 00 75 91 e8 7f da 81 80 00 01 00 04 00 00 00 00 04 74 69 6d 65 05 61 70 70 6c 65 03 63 6f 6d 00 00 01 00 01 c0 0c 00 05 00 01 00 00 0c fb 00 11 04 74 69 6d 65 01 67 07 61 61 70 6c 69 6d 67 c0 17 c0 2c 00 01 00 01 00 00 03 04 00 04 11 fd 74 fd c0 2c 00 01 00 01 00 00 03 04 00 04 11 fd 74 7d c0 2c 00 01 00 01 00 00 03 04 00 04 11 fd 54 fb Unfortunately, it seems the packet is not being written back correctly to the TUN interface. I'm not seeing any expected DNS response behavior on the device. Also, I noticed that after creating the TUN, the interface address shows up as 0.0.0.0:0 in Xcode. The system log includes this message when connecting the VPN: NWPath does not have valid interface: satisfied (Path is satisfied), interface: utun20[endc_sub6], ipv4, dns, expensive, uses cellular Does anyone know how to properly initialize the TUN so that the system recognizes it with a valid IP configuration? Or why my written-back packet might be getting ignored? Any help would be appreciated!

ios構成プロファイルの制限のallowCloudPrivateRelayのプライベートリレーの制御とRelayペイロードの機能は関係がありますか？ それとも別々の機能でしょうか？ ↓ s there a relationship between the private relay control in the iOS configuration profile restriction allowCloudPrivateRelay and the functionality of the Relay payload? Or are they separate features?

Are the network relays introduced in 2023 and https://developer.apple.com/videos/play/wwdc2023/10002/ the same thing as the Private Relay introduced in 2021? https://developer.apple.com/videos/play/wwdc2021/10096/ We are considering verifying the relay function, but we are not sure whether they are the same function or different functions. https://developer.apple.com/documentation/devicemanagement/relay?language=objc

I'm using NWBrowser to search for a server that I hosted. The browser does find my service but when it tries to connect to it, it gets stuck in the preparing phase in NWConnection.stateUpdateHandler. When I hardcode the local IP address of my computer (where the server is hosted) into NWConnection it works perfectly fine and is able to connect. When it gets stuck in the preparing phase, it gives me the warnings and error messages in the image below. You can also see that the service name is correct and it is found. I have tried _http._tcp and _ssh._tcp types and neither work. This is what my code looks like: func findServerAndConnect(port: UInt16) { print("Searching for server...") let browser = NWBrowser(for: .bonjour(type: "_ssh._tcp", domain: "local."), using: .tcp) browser.browseResultsChangedHandler = { results, _ in print("Found results: \(results)") for result in results { if case let NWEndpoint.service(name, type_, domain, interface) = result.endpoint { if name == "PocketPadServer" { print("Found service: \(name) of type \(type_) in domain \(domain) on interface \(interface)") // Construct the full service name, including type and domain let fullServiceName = "\(name).\(type_).\(domain)" print("Full service name: \(fullServiceName), \(result.endpoint)") self.connect(to: result.endpoint, port: port) browser.cancel() break } } } } browser.start(queue: .main) } func connect(to endpoint: NWEndpoint, port: UInt16) { print("Connecting to \(endpoint) on port \(port)...") // endpoint = NWEndpoint( let tcpParams = NWProtocolTCP.Options() tcpParams.enableFastOpen = true tcpParams.keepaliveIdle = 2 let params = NWParameters(tls: nil, tcp: tcpParams) params.includePeerToPeer = true // connection = NWConnection(host: NWEndpoint.Host("xx.xxx.xxx.xxx"), port: NWEndpoint.Port(3000), using: params) connection = NWConnection(to: endpoint, using: params) connection?.pathUpdateHandler = { path in print("Connection path update: \(path)") if path.status == .satisfied { print("Connection path is satisfied") } else { print("Connection path is not satisfied: \(path.status)") } } connection?.stateUpdateHandler = { newState in DispatchQueue.main.async { switch newState { case .ready: print("Connected to server") self.pairing = true self.receiveMessage() case .failed(let error): print("Connection failed: \(error)") self.isConnected = false case .waiting(let error): print("Waiting for connection... \(error)") self.isConnected = false case .cancelled: print("Connection cancelled") self.isConnected = false case .preparing: print("Preparing connection...") self.isConnected = false default: print("Connection state changed: \(newState)") break } } } connection?.start(queue: .main) }

Every now and again folks notice that Network framework seems to create an unexpected number of connections on the wire. This post explains why that happens and what you should do about it. If you have questions or comments, put them in a new thread here on the forums. Use the App & System Services > Networking topic area and the Network tag. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" Understanding Also-Ran Connections Network framework implements the Happy Eyeballs algorithm. That might create more on-the-wire connections than you expect. There are two common places where folks notice this: When looking at a packet trace When implementing a listener Imagine that you’ve implemented a TCP server using NWListener and you connect to it from a client using NWConnection. In many situations there are multiple network paths between the client and the server. For example, on a local network there’s always at least two paths: the link-local IPv6 path and either an infrastructure IPv4 path or the link-local IPv4 path. When you start your NWConnection, Network framework’s Happy Eyeballs algorithm might [1] start a TCP connection for each of these paths. It then races those connections. The one that connects first is the ‘winner’, and Network framework uses that connection for your traffic. Once it has a winner, the other connections, the also-ran connections, are redundant, and Network framework just closes them. You can observe this behaviour on the client side by looking in the system log. Many Network framework log entries (subsystem com.apple.network) contain a connection identifier. For example C8 is the eighth connection started by this process. Each connection may have child connections (C8.1, C8.2, …) and grandchild connections (C8.1.1, C8.1.2, …), and so on. You’ll see state transitions for these child connections occurring in parallel. For example, the following log entries show that C8 is racing the connection of two grandchild connections, C8.1.1 and C8.1.2: type: debug time: 12:22:26.825331+0100 process: TestAlsoRanConnections subsystem: com.apple.network category: connection message: nw_socket_connect [C8.1.1:1] Calling connectx(…) type: debug time: 12:22:26.964150+0100 process: TestAlsoRanConnections subsystem: com.apple.network category: connection message: nw_socket_connect [C8.1.2:1] Calling connectx(…) Note For more information about accessing the system log, see Your Friend the System Log. You also see this on the server side, but in this case each connection is visible to your code. When you connect from the client, Network framework calls your listener’s new connection handler with multiple connections. One of those is the winning connection and you’ll receive traffic on it. The others are the also-ran connections, and they close promptly. IMPORTANT Depending on network conditions there may be no also-ran connections. Or there may be lots of them. If you want to test the also-ran connection case, use Network Link Conditioner to add a bunch of delay to your packets. You don’t need to write special code to handle also-ran connections. From the perspective of your listener, these are simply connections that open and then immediately close. There’s no difference between an also-ran connection and, say, a connection from a client that immediately crashes. Or a connection generated by someone doing a port scan. Your server must be resilient to such things. However, the presence of these also-ran connections can be confusing, especially if you’re just getting started with Network framework, and hence this post. [1] This is “might” because the exact behaviour depends on network conditions. More on that below.

I have an iOS app which contains a Network Extension that subclasses the NEPacketTunnelProvider, acting as a packet-tunnel VPN. After deploying the app on the device as a regular app, it runs the following code fragment: NETunnelProviderManager.loadAllFromPreferences { managers, _ in self.manager = managers?.first ?? NETunnelProviderManager() self.manager.protocolConfiguration = getConfiguration() self.manager.saveToPreferences { error in // Handle errors or show a "Connect" button in the UI } } This asks the user to install the extension as a "Device VPN". I can then use try? self.manager?.connection.startVPNTunnel() to start the VPN (and later stop it when needed). So far, this works fine. Now, I want to deploy the app with an MDM and set it up as the "custom VPN" of a "Per-App VPN". I have tested the setup using a real MDM, AND using the "development" setup described in NETunnelProviderManager. In both cases, the "Per-App VPN" shows up as a VPN in the "Settings" app. However, in both cases I am unable to retrieve, configure or use the "Per-App VPN". The code fragment posted above returns no NETunnelProviderManager at all. When instantiating one on my own and triggering self.manager.saveToPreferences(), it queries the user to install a "Device VPN". While I can control and use the latter, this is clearly not what I want after having gone through the pain of installing the "Per-App VPN". How can I retrieve the NETunnelProviderManager of the "Per-App VPN"? And then use it to configure and control the VPN connection? (Ideally, I would like to use the same app and the same Network Extension for both use cases, leaving the choice of which VPN type to use to the user or the user's MDM administrator.)

I had noticed that my slaac address changed between one beta and the other, but wasn't sure. Now with the RC 15.4 RC (24E247) I made point of preserving the info before updating from the previous beta. What I noticed is that not only the slaac address changes, but also the my ether address, even though I have it on Fixed in the settings. Is it expected that the ether, and the slaac, not be rotated after a OS update?

Hi All, I am trying to write an NWProtocolFramerImplementation that will run after Websockets. I would like to achieve two goals with this Handle the application-layer authentication handshake in-protocol so my external application code can ignore it Automatically send pings periodically so my application can ignore keepalive I am running into trouble because the NWProtocolWebsocket protocol parses websocket metadata into NWMessage's and I don't see how to handle this at the NWProtocolFramerImplementation level Here's what I have (see comments for questions) class CoolProtocol: NWProtocolFramerImplementation { static let label = "Cool" private var tempStatusCode: Int? required init(framer: NWProtocolFramer.Instance) {} static let definition = NWProtocolFramer.Definition(implementation: CoolProtocol.self) func start(framer: NWProtocolFramer.Instance) -> NWProtocolFramer.StartResult { return .willMarkReady } func wakeup(framer: NWProtocolFramer.Instance) { } func stop(framer: NWProtocolFramer.Instance) -> Bool { return true } func cleanup(framer: NWProtocolFramer.Instance) { } func handleOutput(framer: NWProtocolFramer.Instance, message: NWProtocolFramer.Message, messageLength: Int, isComplete: Bool) { // How to write a "Message" onto the next protocol handler. I don't want to just write plain data. // How to tell the websocket protocol framer that it's a ping/pong/text/binary... } func handleInput(framer: NWProtocolFramer.Instance) -> Int { // How to handle getting the input from websockets in a message format? I don't want to just get "Data" I would like to know if that data is // a ping, pong, text, binary, ... } } If I implementing this protocol at the application layer, here's how I would send websocket messages class Client { ... func send(string: String) async throws { guard let data = string.data(using: .utf8) else { return } let metadata = NWProtocolWebSocket.Metadata(opcode: .text) let context = NWConnection.ContentContext( identifier: "textContext", metadata: [metadata] ) self.connection.send( content: data, contentContext: context, isComplete: true, completion: .contentProcessed({ [weak self] error in ... }) ) } } You see at the application layer I have access to this context object and can access NWProtocolMetadata on the input and output side, but in NWProtocolFramer.Instance I only see final func writeOutput(data: Data) which doesn't seem to include context anywhere. Is this possible? If not how would you recommend I handle this? I know I could re-write the entire Websocket protocol framer, but it feels like I shouldn't have to if framers are supposed to be able to stack.

Hi folks, I'm building an iOS companion app to a local hosted server app (hosted on 0.0.0.0). The MacOS app locally connects to this server hosted, and I took the approach of advertising the server using a Daemon and BonjourwithTXT(for port) and then net service to resolve a local name. Unfortunately if there's not enough time given after the iPhone/iPad is plugged in (usb or ethernet), the app will cycle through attempts and disconnects many times before connecting and I'm trying to find a way to only connect when a viable en interface is available. I've run into a weird thing in which the en interface only becomes seen on the NWMonitor after multiple connection attempts have been made and failed. If I screen for en before connecting it simply never appears. Is there any way to handle this such that my app can intelligently wait for an en connection before trying to connect? Attaching my code although I have tried a few other setups but none has been perfect. func startMonitoringAndBrowse() { DebugLogger.shared.append("Starting Bonjour + Ethernet monitoring") if !browserStarted { let params = NWParameters.tcp params.includePeerToPeer = false params.requiredInterfaceType = .wiredEthernet browser = NWBrowser(for: .bonjourWithTXTRecord(type: "_mytcpapp._tcp", domain: nil), using: params) browser?.stateUpdateHandler = { state in if case .ready = state { DebugLogger.shared.append("Bonjour browser ready.") } } browser?.browseResultsChangedHandler = { results, _ in self.handleBrowseResults(results) } browser?.start(queue: .main) browserStarted = true } // Start monitoring for wired ethernet monitor = NWPathMonitor() monitor?.pathUpdateHandler = { path in let hasEthernet = path.availableInterfaces.contains { $0.type == .wiredEthernet } let ethernetInUse = path.usesInterfaceType(.wiredEthernet) DebugLogger.shared.append(""" NWPathMonitor: - Status: \(path.status) - Interfaces: \(path.availableInterfaces.map { "\($0.name)[\($0.type)]" }.joined(separator: ", ")) - Wired Ethernet: \(hasEthernet), In Use: \(ethernetInUse) """) self.tryToConnectIfReady() self.stopMonitoring() } monitor?.start(queue: monitorQueue) } // MARK: - Internal Logic private func handleBrowseResults(_ results: Set<NWBrowser.Result>) { guard !self.isResolving, !self.hasResolvedService else { return } for result in results { guard case let .bonjour(txtRecord) = result.metadata, let portString = txtRecord["actual_port"], let actualPort = Int(portString), case let .service(name, type, domain, _) = result.endpoint else { continue } DebugLogger.shared.append("Bonjour result — port: \(actualPort)") self.resolvedPort = actualPort self.isResolving = true self.resolveWithNetService(name: name, type: type, domain: domain) break } } private func resolveWithNetService(name: String, type: String, domain: String) { let netService = NetService(domain: domain, type: type, name: name) netService.delegate = self netService.includesPeerToPeer = false netService.resolve(withTimeout: 5.0) resolvingNetService = netService DebugLogger.shared.append("Resolving NetService: \(name).\(type)\(domain)") } private func tryToConnectIfReady() { guard hasResolvedService, let host = resolvedHost, let port = resolvedPort else { return } DebugLogger.shared.append("Attempting to connect: \(host):\(port)") discoveredIP = host discoveredPort = port connectionPublisher.send(.connecting(ip: host, port: port)) stopBrowsing() socketManager.connectToServer(ip: host, port: port) hasResolvedService = false } } // MARK: - NetServiceDelegate extension BonjourManager: NetServiceDelegate { func netServiceDidResolveAddress(_ sender: NetService) { guard let hostname = sender.hostName else { DebugLogger.shared.append("Resolved service with no hostname") return } DebugLogger.shared.append("Resolved NetService hostname: \(hostname)") resolvedHost = hostname isResolving = false hasResolvedService = true tryToConnectIfReady() } func netService(_ sender: NetService, didNotResolve errorDict: [String : NSNumber]) { DebugLogger.shared.append("NetService failed to resolve: \(errorDict)") } }

When I use NSURLSessionTaskTransactionMetrics property domainLookupStartDate and domainLookupEndDate to calculate the duration of DNS, sometimes I get 4294893875545978 or -4294893875545978 return method like this [NSNumber numberWithLongLong:[taskMetrics.domainLookupEndDate timeIntervalSinceDate:taskMetrics.domainLookupStartDate?]*1000000000] The hexadecimal value of 4294893875545978 is 0xF3F3F3F3F3F3A. Is 4294893875545978 a special value？

We’re looking to implement a custom IPSec IKEv2 VPN using the Packet Tunnel Provider network extension on iOS because we need to add extra information to EAP, which the built-in IKEv2 VPN configuration does not support. Is it possible to handle the full IKEv2 negotiation and IPSec tunneling within the Packet Tunnel Provider extension? Or are there limitations that would prevent implementing a full IKEv2 stack this way? Any insights or alternative approaches would be appreciated. Thanks!

Just bought a macbook pro m4, im trying to run an api on port 5000, disabled airplay receiver, checked processes, ghost ones, hidden ones, and stuck ones. I didn't find a thing using the port, but i still get port in use.

I’m developing an app designed for hospital environments, where public internet access may not be available. The app includes two components: the main app and a Local Connectivity Extension. Both rely on persistent TCP socket connections to communicate with a local server. We’re observing a recurring issue where the extension’s socket becomes unresponsive every 1–3 hours, but only when the device is on the lock screen, even if the main app remains in the foreground. When the screen is not locked, the connection is stable and no disconnections occur. ❗ Issue Details: • What’s going on: The extension sends a keep-alive ping packet every second, and the server replies with a pong and a system time packet. • The bug: The server stops receiving keep alive packets from the extension.  • On the server, we detect about 30 second gap on the server, a gap that shows no packets were received by the extension. This was confirmed via server logs and Wireshark).  • On the extension, from our logs there was no gap in sending packets. From it’s perspective, all packets were sent with no error.  • Because no packet are being received by the server, no packets will be sent to the extension. Eventually the server closes the connection due to keep-alive timeout.  • FYI we log when the NEAppPushProvider subclass sleeps and it did NOT go to sleep while we were debugging. 🧾 Example Logs: Extension log: 2025-03-24 18:34:48.808 sendKeepAliveRequest() 2025-03-24 18:34:49.717 sendKeepAliveRequest() 2025-03-24 18:34:50.692 sendKeepAliveRequest() ... // continuous sending of the ping packet to the server, no problems here 2025-03-24 18:35:55.063 sendKeepAliveRequest() 2025-03-24 18:35:55.063 keepAliveTimer IS TIME OUT... in CoreService. // this is triggered because we did not receive any packets from the server 2025-03-24 18:34:16.298 No keep-alive received for 16 seconds... connection ID=95b3... // this shows that there has been no packets being received by the extension ... 2025-03-24 18:34:30.298 Connection timed out on keep-alive. connection ID=95b3... // eventually closes due to no packets being received 2025-03-24 18:34:30.298 Remote Subsystem Disconnected {name=iPhone|Replica-Ext|...} ✅ Observations: • The extension process continues running and logging keep-alive attempts. • However, network traffic stops reaching the server, and no inbound packets are received by the extension. • It looks like the socket becomes silently suspended or frozen, without being properly closed or throwing an error. ❓Questions: • Do you know why this might happen within a Local Connectivity Extension, especially under foreground conditions and locked ? • Is there any known system behavior that might cause the socket to be suspended or blocked in this way after running for a few hours? Any insights or recommendations would be greatly appreciated. Thank you!

Please consider this very trivial C code, which was run on 15.3.1 of macos: #include <stdio.h> #include <stdlib.h> #include <netinet/in.h> #include <arpa/inet.h> #include "sys/socket.h" #include <string.h> #include <unistd.h> #include <ifaddrs.h> #include <net/if.h> // prints out the sockaddr_in6 void print_addr(const char *msg_prefix, struct sockaddr_in6 sa6) { char addr_text[INET6_ADDRSTRLEN] = {0}; printf("%s%s:%d, addr family=%u\n", msg_prefix, inet_ntop(AF_INET6, &sa6.sin6_addr, (char *) &addr_text, INET6_ADDRSTRLEN), sa6.sin6_port, sa6.sin6_family); } // creates a datagram socket int create_dgram_socket() { const int fd = socket(AF_INET6, SOCK_DGRAM, 0); if (fd < 0) { perror("Socket creation failed"); return -1; } return fd; } int main() { printf("current process id:%ld parent process id: %ld\n", (long) getpid(), (long) getppid()); // // hardcode a link-local IPv6 address of a interface which is down // ifconfig: // ,,, // awdl0: flags=8822<BROADCAST,SMART,SIMPLEX,MULTICAST> mtu 1500 // options=6460<TSO4,TSO6,CHANNEL_IO,PARTIAL_CSUM,ZEROINVERT_CSUM> // ... // inet6 fe80::34be:50ff:fe14:ecd7%awdl0 prefixlen 64 scopeid 0x10 // nd6 options=201<PERFORMNUD,DAD> // media: autoselect (<unknown type>) // status: inactive // const char *ip6_addr_str = "fe80::34be:50ff:fe14:ecd7"; // link-local ipv6 address from above ifconfig output // parse the string literal to in6_addr struct in6_addr ip6_addr; int rv = inet_pton(AF_INET6, ip6_addr_str, &ip6_addr); if (rv != 1) { fprintf(stderr, "failed to parse ipv6 addr %s\n", ip6_addr_str); exit(EXIT_FAILURE); } // create a AF_INET6 SOCK_DGRAM socket const int sock_fd = create_dgram_socket(); if (sock_fd < 0) { exit(EXIT_FAILURE); } printf("created a socket, descriptor=%d\n", sock_fd); // create a destination sockaddr which points to the above // ipv6 link-local address and an arbitrary port const int dest_port = 12345; struct sockaddr_in6 dest_sock_addr; memset((char *) &dest_sock_addr, 0, sizeof(struct sockaddr_in6)); dest_sock_addr.sin6_addr = ip6_addr; dest_sock_addr.sin6_port = htons(dest_port); dest_sock_addr.sin6_family = AF_INET6; dest_sock_addr.sin6_scope_id = 0x10; // scopeid from the above ifconfig output // now sendto() to that address, whose network interface is down. // we expect sendto() to return an error print_addr("sendto() to ", dest_sock_addr); const char *msg = "hello"; const size_t msg_len = strlen(msg) + 1; rv = sendto(sock_fd, msg, msg_len, 0, (struct sockaddr *) &dest_sock_addr, sizeof(dest_sock_addr)); if (rv == -1) { perror("sendto() expectedly failed"); close(sock_fd); exit(EXIT_FAILURE); } printf("sendto() unexpectedly succeeded\n"); // should not reach here, we expect sendto() to return an error return 0; } It creates a SOCK_DGRAM socket and attempts to sendto() to a link-local IPv6 address of a local network interface which is not UP. The sendto() is expected to fail with a "network is down" (or at least fail with some error). Let's see how it behaves. Copy that code to a file called netdown.c and compile it as follows: clang netdown.c Now run the program: ./a.out That results in the following output: current process id:29290 parent process id: 21614 created a socket, descriptor=3 sendto() to fe80::34be:50ff:fe14:ecd7:14640, addr family=30 sendto() unexpectedly succeeded (To reproduce this locally, replace the IPv6 address in that code with a link-local IPv6 address of an interface that is not UP on your system) Notice how the sendto() returned successfully without any error giving an impression to the application code that the message has been sent. In reality, the message isn't really sent. Here's the system logs from that run: PID Type Date & Time Process Message debug 2025-03-13 23:36:36.830147 +0530 kernel Process (a.out) allowed via dev tool environment (/System/Applications/Utilities/Terminal.app/Contents/MacOS/Terminal) debug 2025-03-13 23:36:36.833054 +0530 kernel [SPI][HIDSPI] TX: 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 RX: 20 02 00 00 00 00 38 00 10 02 00 17 00 00 2E 00 26700 error 2025-03-13 23:36:36.838607 +0530 nehelper Failed to get the signing identifier for 29290: No such process 26700 error 2025-03-13 23:36:36.838608 +0530 nehelper Failed to get the code directory hash for 29290: No such process default 2025-03-13 23:36:36.840070 +0530 kernel cfil_dispatch_attach_event:3507 CFIL: Failed to get effective audit token for <sockID 22289651233205710 <4f3051d7ec2dce>> 26700 error 2025-03-13 23:36:36.840678 +0530 nehelper Failed to get the signing identifier for 29290: No such process 26700 error 2025-03-13 23:36:36.840679 +0530 nehelper Failed to get the code directory hash for 29290: No such process default 2025-03-13 23:36:36.841742 +0530 kernel cfil_hash_entry_log:6082 <CFIL: Error: sosend_reinject() failed>: [29290 ] <UDP(17) out so 891be95f39bd0385 22289651233205710 22289651233205710 age 0> lport 60244 fport 12345 laddr fe80::34be:50ff:fe14:ecd7 faddr fe80::34be:50ff:fe14:ecd7 hash D7EC2DCE default 2025-03-13 23:36:36.841756 +0530 kernel cfil_service_inject_queue:4466 CFIL: sosend() failed 50 Notice the last line where it states the sosend() (and internal impl detail of macos) failed with error code 50, which corresponds to ENETDOWN ("Network is down"). However, like I noted, this error was never propagated back to the application from the sendto() system call. The documentation of sendto() system call states: man sendto ... Locally detected errors are indicated by a return value of -1. ... RETURN VALUES Upon successful completion, the number of bytes which were sent is returned. Otherwise, -1 is returned and the global variable errno is set to indicate the error. So I would expect sendto() to return -1, which it isn't. The 15.3.1 source of xnu hasn't yet been published but there is the 15.3 version here https://github.com/apple-oss-distributions/xnu/tree/xnu-11215.81.4 and looking at the corresponding function cfil_service_inject_queue, line 4466 (the one which is reported in the logs) https://github.com/apple-oss-distributions/xnu/blob/xnu-11215.81.4/bsd/net/content_filter.c#L4466, the code there logs this error and the cfil_service_inject_queue function then returns back the error. However, looking at the call sites of the call to cfil_service_inject_queue(...), there are several places within that file which don't track the return value (representing an error value) and just ignore it. Is that intentional and does that explain this issue? Does this deserve to be reported as a bug through feedback assistant?

We have a NEFilterDataProvider extension that intercepts all TCP and UDP IPv4/6 traffic. At times just after wakeup from sleep, it causes internet access issues, such as showing "This site can't be reached" when opening websites. The traffic is not being dropped by the extension. According to the logs, the connection is being closed after approximately 4 minutes. During the issue, the flow logs are as follows: Flow 515129771 is connecting New flow: NEFlow type = stream, app = com.google.Chrome.helper... Detaching, ref count = 2 (logged after ~4 minutes) Sending close, how = 2 Removing from group 2, ref count = 2 Destroying, app tx 0, tunnel tx 0, tunnel rx 0 Closing reads, not closed by plugin Closing writes, not sending close Any suggestions on the possible cause and how to further debug it?

Hi all, I work on a smart product that, for setup, uses a captive portal to allow users to connect and configure the device. It emits a WiFi network and runs a captive portal - an HTTP server operates at 10.0.0.1, and a DNS server responds to all requests with 10.0.0.1 to direct "any and all" request to the server. When iOS devices connect, they send a request to captive.apple.com/hotspot-detect.html; if it returns success, that means they're on the internet; if not, the typical behavior in the past has been to assume you're connected to a captive portal and display what's being served. I serve any requests to /hotspot-detect.html with my captive portal page (index.html). This has worked reliably on iOS18 for a long time (user selects my products WiFi network, iOS detects portal and opens it). But almost everyone who's now trying with iOS26 is having the "automatic pop up" behavior fail - usually it says "Error opening page - Hotspot login cannot open the page because the network connection was lost." However, if opening safari and navigating to any URL (or 10.0.0.1) the portal loads - it's just the iOS auto-detect and open that's not working iOS18 always succeeds; iOS26 always fails. Anybody have any idea what changes may have been introduced in iOS26 on this front, or anything I can do to help prompt or coax iOS26 into loading the portal? It typically starts reading, but then stops mid-read.