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 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. 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 Network Extension (including Wi-Fi on iOS): See Network Extension Resources Wi-Fi Fundamentals TN3111 iOS Wi-Fi API overview Wi-Fi Aware framework documentation Wi-Fi on macOS: Forums tag: Core WLAN Core WLAN framework documentation Wi-Fi Fundamentals Secure networking: Forums tags: Security Apple Platform Security support document Preventing Insecure Network Connections documentation — This is all about App Transport Security (ATS). 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. 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 WirelessInsights framework documentation iOS Network Signal Strength Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com"

Around 8/23/25, I installed macOS 15.6.1 on my work Mac. After this I can no longer log the application I am working on into our backend servers. My work Mac is running Palo Alto Global Protect VPN software along with a bunch of associated security software to lock down my computer. I had no issues with connecting to our backend servers behind the firewall before the macOS update and nothing has changed in the source code related to this. When I send the username the network call just hangs and never times out. On the other hand, if I turn off the VPN and point to the production environment the call succeeds with no problems. Any Ideas?

Hi Apple Development forums, I am having trouble getting a Wireguard VPN config setup to automatically disconnect on all domain requests other than one specific domain. I have my .mobileconfig designed as so: <dict> <key>Action</key> <string>EvaluateConnection</string> <key>ActionParameters</key> <array> <dict> <key>Domains</key> <array> <string>service.domainname.com</string> </array> <key>DomainAction</key> <string>ConnectIfNeeded</string> <key>ProbeURL</key> <string>https://service.domainname.com/</string> </dict> </array> </dict> <dict> <key>Action</key> <string>Disconnect</string> <key>DNSDomainMatch</key> <array> <string>*.com</string> <string>*.org</string> <string>*.net</string> </array> </dict> <dict> <key>Action</key> <string>Disconnect</string> </dict> </array> The issue I'm having is regardless of whether I note a *.com or simply have the action Disconnect noted - the VPN stays connected after navigating to https://service.domainname.com. would anyone have any thoughts on this? Or am I missing something here?

Furuno AP(EW750) is sending EAPOL M1 message, but Iphone16 is not responding with EAPOL M2 message, Hence Iphone16 is unable to connect to Qualcomm based AP with MLO suiteb encryption. Issue impact: All the Iphone16 users cannot connect to WiFi7 AP with MLO suiteb encryption globally. Predominantly, Iphone users tend to connect to more secured wifi networks using WPA3 suiteb encryption, hence many of the iphone users will experience the connectivity issue significantly. Topology: AP Hardware: Furuno WiFi7 AP(EW770) The Furuno WiFi7 AP uses Miami IPQ5332 with waikiki radio QCN9274 (Qualcomm based chipset) AP software: SPF12.2 CSU3 IPhone16 software: (18.3.1 or 18.5 ) I phone16 wifi capabilities: 802.11 b/a/g/n/ac/ax/be Radius server details: Radius server: Laptop running with Ubuntu Radius package: 3.0.26dfsggit20220223.1.00ed0241fa-0ubuntu3.4 Version: 3.0.26 Steps: Power on the Wi-Fi 7 Access Point with the Miami chipset, and flash it with the SPF 12.2 CSU3 image. Enable both 5 GHz and 6 GHz radios on the AP. Enable MLO (Multi-Link Operation) in 6Ghz & 5Ghz, set MLD address different from radio address and configure Suite-B (192-bit) encryption On the Linux laptop, set up the RADIUS server with EAP-TLS authentication method. Once the above steps are completed, take the iPhone 16 and follow the steps below to install the RADIUS client certificates on the device. On the sniffer laptop, switch the Wi-Fi adapter to monitor mode, configure the required channel, and begin packet capture. Check SSID is broadcasting, then connect the iPhone 16 to . Verify if the client (iPhone 16) connects to the SSID using WPA3-Enterprise, MLO, and Suite-B encryption by checking the wireless capture on both the AP and iPhone sides. Support needed from Apple team: We would request Apple team to analyse and enable the IPhone16 users to connect to advanced security WPA3 Suiteb by resolving the issue. Below is our analysis and observation for your reference. As per IEEE, MLD mac address can be set to the same or different from radio address, Iphone16 is not accepting EAPOL M1 message if source address(MLD) is different from radio address. IPhone16 is accepting EAPOL M1 if the source address(MLD) is set to the same as the radio address and responds with M2 message IPhone16 is not accepting EAPOL M1 if source address(MLD) set to different from radio address and fails to respond with M2 message. sysdiagnose.log log-file log-file Please let us know additional logs are required.

I investigated what network interface names are assigned to carrier networks on a dual SIM iPhone by examining the output of getifaddrs(). (An part of the program used for this is provided below.) ////////////// struct ifaddrs *interfaces = NULL; struct ifaddrs *an_interface = NULL; if (0 == getifaddrs(&interfaces)) { an_interface = interfaces; while (an_interface != NULL) { if( an_interface->ifa_addr->sa_family == AF_INET) { NSString* name = [NSString stringWithUTF8String:an_interface->ifa_name]; NSLog(@"Interface name is: %@", name); } an_interface = an_interface->ifa_next; } } freeifaddrs(interfaces); In this investigation, it appeared that the interface name for the sXGP SIM selected under "iPhone > Settings > Cellular > Cellular Data" was always "pdp_ip0". (A screenshot of "Cellular Data" is provided below. this is sample of sXGP selected )" [QUESTION] Is the SIM selected in Settings of iPhone always assigned to "pdp_ip0"? [BACKGROUND] I am developing a VoIP application and opening sockets by specifying IP addresses for communication. On a dual SIM iPhone, multiple networks (IP addresses) are visible. Therefore, I need to determine which network to use. My question is whether I can reliably make this decision based on the network interface name. If the SIM selected in Settings is always assigned to "pdp_ip0", I intend to open the socket using the IP address of "pdp_ip0". Alternatively, should I use a different method to select the appropriate network interface?

Development environment Xcode 26.0 Beta 6 iOS 26 Simulator macOS 15.6.1 To verify TLS 1.3 session resumption behavior in URLSession, I configured URLSessionConfiguration as follows and sent an HTTP GET request: let config = URLSessionConfiguration.ephemeral config.tlsMinimumSupportedProtocolVersion = .TLSv13 config.tlsMaximumSupportedProtocolVersion = .TLSv13 config.httpMaximumConnectionsPerHost = 1 config.httpAdditionalHeaders = ["Connection": "close"] config.enablesEarlyData = true let session = URLSession(configuration: config, delegate: nil, delegateQueue: nil) let url = URL(string: "https://www.google.com")! var request = URLRequest(url: url) request.assumesHTTP3Capable = true request.httpMethod = "GET" let task = session.dataTask(with: request) { data, response, error in if let error = error { print("Error during URLSession data task: \(error)") return } if let data = data, let responseString = String(data: data, encoding: .utf8) { print("Received data via URLSession: \(responseString)") } else { print("No data received or data is not UTF-8 encoded") } } task.resume() However, after capturing the packets, I found that the ClientHello packet did not include the early_data extension. It seems that enablesEarlyData on URLSessionConfiguration is not being applied. How can I make this work properly?

iOS Development environment Xcode 16.4, macOS 15.6.1 (24G90) Run-time configuration: iOS 17.2+ Short Description After having successfully established an NWConnection (either as UDP or TCP), and subsequently receiving the error code: UDP Connection failed: 57 The operation couldn't be completed. (Network.NWError error 57 - Socket is not connected), available Interfaces: [enO] via NWConnection.stateUpdateHandler = { (newState) in ... } while newState == .failed the data connection does not restart by itself once cellular (RF) telephony coverage is established again. Detailed Description Context: my app has a continuous cellular data connection while in use. Either a UDP or a TCP connection is established depending on the user settings. The setup data connection works fine until the data connection gets disconnected by loss of connection to a available cellular phone base station. This disconnection simply occurs in very poor UMTS or GSM cellular phone coverage. This is totally normal behavior in bad reception areas like in mountains with signal loss. STEPS TO REPRODUCE Pre-condition App is running with active data connection. Action iPhone does loss the cellular data connection previously setup. Typically reported as network error code 57. Observed The programmed connection.stateUpdateHandler() is called in network connection state '.failed' (OK). The self-programmed data re-connection includes: a call to self.connection.cancel() a call to self.setupUDPConnection() or self.setupConnection() depending on the user settings to re-establish an operative data connection. However, the iPhone's UMTS/GSM network data (re-)connection state is not properly identified/notified via NWConnection API. There's no further network state notification by means of NWConnection even though the iPhone has recovered a cellular data network. Expected The iPhone or any other means automatically reconnects the interrupted data connection on its own. The connection.stateUpdateHandler() is called at time of the device's networking data connection (RF) recovering, subsequently to a connection state failed with error code 57, as the RF module is continuously (independently from the app) for available telephony networks. QUESTION How to systematically/properly detect a cellular phone data network reconnection readiness in order to causally reinitialize the NWConnection data connection available used in app. Relevant code extract Setup UDP connection (or similarly setup a TCP connection) func setupUDPConnection() { let udp = NWProtocolUDP.Options.init() udp.preferNoChecksum = false let params = NWParameters.init(dtls: nil, udp: udp) params.serviceClass = .responsiveData // service type for medium-delay tolerant, elastic and inelastic flow, bursty, and long-lived connections connection = NWConnection(host: NWEndpoint.Host.name(AppConstant.Web.urlWebSafeSky, nil), port: NWEndpoint.Port(rawValue: AppConstant.Web.urlWebSafeSkyPort)!, using: params) connection.stateUpdateHandler = { (newState) in switch (newState) { case .ready: //print("UDP Socket State: Ready") self.receiveUDPConnection(). // data reception works fine until network loss break case .setup: //print("UDP Socket State: Setup") break case .cancelled: //print("UDP Socket State: Cancelled") break case .preparing: //print("UDP Socket State: Preparing") break case .waiting(let error): Logger.logMessage(message: "UDP Connection waiting: "+error.errorCode.description+" \(error.localizedDescription), available Interfaces: \(self.connection.currentPath!.availableInterfaces.description)", LoggerLevels.Error) break case .failed(let error): Logger.logMessage(message: "UDP Connection failed: "+error.errorCode.description+" \(error.localizedDescription), available Interfaces: \(self.connection.currentPath!.availableInterfaces.description)", LoggerLevels.Error) // data connection retry (expecting network transport layer to be available) self.reConnectionServer() break default: //print("UDP Socket State: Waiting or Failed") break } self.handleStateChange() } connection.start(queue: queue) } Handling of network data connection loss private func reConnectionServer() { self.connection.cancel() // Re Init Connection - Give a little time to network recovery let delayInSec = 30.0. // expecting actually a notification for network data connection availability, instead of a time-triggered retry self.queue.asyncAfter(deadline: .now() + delayInSec) { switch NetworkConnectionType { case 1: self.setupUDPConnection() // UDP break case 2: self.setupConnection() // TCP break default: break } } } Does it necessarily require the use of CoreTelephony class CTTelephonyNetworkInfo or class CTCellularData to get notifications of changes to the user’s cellular service provider?

I have an app with lots of networking calls that are currently done through URLSession. We would like to implement the new carried constrained entitlements and begin moving data through the ultra constrained network path for core features of our application. I have successfully implemented the NWPathMonitor to identify when the current network path is ultra constrained and I have been consistently on a physical device in a real world environment. I'm aware that we will not be able to use URLSession to do this from other posts in this forum like this one. Because of this problem with URLSession I am attempting to fallback to using NWConnection when the current path is ultra constrained. I have setup a NWConnection with the NWParameters.allowUltraConstrainedPaths set to true. The request works perfectly when connected to wifi or cellular. However, it does not work at all when the current path is ultra constrained. When attempting this request through my NWConnection I receive an error that says: The operation couldn’t be completed. (Network.NWError error 50 - Network is down) Is this expected? I have confirmed my physical device is connecting to carrier provided satellite and I have been able to load data in other ios apps from Apple like the music app while on this carrier constrained connection. If this is not the correct way to move data when the path is ultra constrained what is the correct way?

I'm currently exploring Instruments for profiling and tracing on macOS 15.6.1. I know there is the "network connections" instrument which records TCP/UDP information, however it seems to not include the "lo0" (loopback) interface. Is there a way to configure it so that localhost traffic is included in the recording? as the application I'm tracing uses that and I want that information to be included in traces. The documentation for network-interface-detection schema makes no mention of how it detects interfaces. Thanks in advance.

The Wi‑Fi Alliance’s Wi‑Fi Aware data communication uses IPv6. However, in Chapter 53 “Wi‑Fi Aware” of the Accessory Design Guidelines for Apple Devices, Release R26, it is stated that “The Neighbor Discovery Protocol (NDP) for IPv6 address resolution is not supported.” This has caused confusion among developers: Does Apple’s Wi‑Fi Aware data communication actually use IPv6? What is the impact of “The Neighbor Discovery Protocol (NDP) for IPv6 address resolution is not supported” in Apple’s implementation?

In Low Power Mode or after the iPhone has been idle, On-Demand rules fire and StartTunnel runs. Subsequent calls to createTCPConnectionThroughTunnel intermittently fail with an error. Is NetworkExtension known to behave differently under Low Power Mode that might cause this?

But the NMI and NDI of Samsung's Wi Fi Aware are not the same MAC address. May I ask Apple engineers why they are different from Samsung？

Hi. We are writing to report a critical issue we've encountered following the recent release of iOS 26 beta 6. After updating our test devices, we discovered that our application is no longer able to establish HTTPS connections to several of our managed FQDNs. This issue was not present in beta 5 and appears to be a direct result of changes introduced in beta 6. The specific FQDNs that are currently unreachable are: d.socdm.com i.socdm.com tg.scodm.com We have reviewed the official iOS & iPadOS 26 Beta 6 Release Notes, particularly the updates related to TLS. While the notes mention changes, we have confirmed that our servers for all affected FQDNs support TLS 1.2, so we believe they should still be compliant. We have also investigated several of Apple's support documents regarding TLS connection requirements (e.g., HT214774, HT214041), but the information does not seem to apply to our situation, and we are currently unable to identify the root cause of this connection failure. https://support.apple.com/en-us/102028 https://support.apple.com/en-us/103214 Although we hope this issue might be resolved in beta 7 or later, the official release is fast approaching, and this has become a critical concern for us. Could you please provide any advice or insight into what might be causing this issue? Any guidance on potential changes in the networking or security frameworks in beta 6 that could affect TLS connections would be greatly appreciated. We have attached the relevant code snippet that triggers the error, along with the corresponding Xcode logs, for your review. Thank you for your time and assistance. #import "ViewController.h" @interface ViewController () @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; NSURL *url = [NSURL URLWithString:@"https://i.socdm.com/sdk/js/adg-script-loader-b-stg.js"]; NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:30.0]; [self sendWithRequest:req completionHandler:^(NSData *_Nullable data, NSHTTPURLResponse *_Nonnull response, NSError *_Nullable error) { if (error){ NSLog(@"Error occurred: %@", error.localizedDescription); return; }else{ NSLog(@"Success! Status Code: %ld", (long)response.statusCode); } }]; } - (void) sendWithRequest:(NSMutableURLRequest *)request completionHandler:(void (^ _Nullable)(NSData *_Nullable data, NSHTTPURLResponse *response, NSError *_Nullable error))completionHandler { NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration]; NSURLSession *session = nil; session = [NSURLSession sessionWithConfiguration:configuration delegate:self delegateQueue:nil]; NSURLSessionTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { [session finishTasksAndInvalidate]; NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *) response; if (error) { if (completionHandler) { completionHandler(nil, httpResponse, error); } } else { if (completionHandler) { completionHandler(data, httpResponse, nil); } } }]; [task resume]; } @end error Connection 1: default TLS Trust evaluation failed(-9807) Connection 1: TLS Trust encountered error 3:-9807 Connection 1: encountered error(3:-9807) Task <C50BB081-E1DA-40FF-A1E5-A03A2C4CB733>.<1> HTTP load failed, 0/0 bytes (error code: -1202 [3:-9807]) Task <C50BB081-E1DA-40FF-A1E5-A03A2C4CB733>.<1> finished with error [-1202] Error Domain=NSURLErrorDomain Code=-1202 "The certificate for this server is invalid. You might be connecting to a server that is pretending to be “i.socdm.com” which could put your confidential information at risk." UserInfo={NSLocalizedRecoverySuggestion=Would you like to connect to the server anyway?, _kCFStreamErrorDomainKey=3, NSErrorPeerCertificateChainKey=( "<cert(0x10621ca00) s: *.socdm.com i: GlobalSign RSA OV SSL CA 2018>", "<cert(0x106324e00) s: GlobalSign RSA OV SSL CA 2018 i: GlobalSign>" ), NSErrorClientCertificateStateKey=0, NSErrorFailingURLKey=https://i.socdm.com/sdk/js/adg-script-loader-b-stg.js, NSErrorFailingURLStringKey=https://i.socdm.com/sdk/js/adg-script-loader-b-stg.js, NSUnderlyingError=0x1062bf960 {Error Domain=kCFErrorDomainCFNetwork Code=-1202 "(null)" UserInfo={_kCFStreamPropertySSLClientCertificateState=0, kCFStreamPropertySSLPeerTrust=<SecTrustRef: 0x10609d140>, _kCFNetworkCFStreamSSLErrorOriginalValue=-9807, _kCFStreamErrorDomainKey=3, _kCFStreamErrorCodeKey=-9807, kCFStreamPropertySSLPeerCertificates=( "<cert(0x10621ca00) s: *.socdm.com i: GlobalSign RSA OV SSL CA 2018>", "<cert(0x106324e00) s: GlobalSign RSA OV SSL CA 2018 i: GlobalSign>" )}}, _NSURLErrorRelatedURLSessionTaskErrorKey=( "LocalDataTask <C50BB081-E1DA-40FF-A1E5-A03A2C4CB733>.<1>" ), _kCFStreamErrorCodeKey=-9807, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <C50BB081-E1DA-40FF-A1E5-A03A2C4CB733>.<1>, NSURLErrorFailingURLPeerTrustErrorKey=<SecTrustRef: 0x10609d140>, NSLocalizedDescription=The certificate for this server is invalid. You might be connecting to a server that is pretending to be “i.socdm.com” which could put your confidential information at risk.} Error occurred: The certificate for this server is invalid. You might be connecting to a server that is pretending to be “i.socdm.com” which could put your confidential information at risk. 折りたたむ

我的完整报错信息： Task &lt;0568A3A0-A40C-42A8-9491-2FC52D71EFFF&gt;.&lt;4&gt; finished with error [-1009] Error Domain=NSURLErrorDomain Code=-1009 "似乎已断开与互联网的连接。" UserInfo={_kCFStreamErrorCodeKey=50, NSUnderlyingError=0x107db5590 {Error Domain=kCFErrorDomainCFNetwork Code=-1009 "(null)" UserInfo={_kCFStreamErrorDomainKey=1, _kCFStreamErrorCodeKey=50, _NSURLErrorNWResolutionReportKey=Resolved 0 endpoints in 1ms using unknown from cache, _NSURLErrorNWPathKey=unsatisfied (Denied over Wi-Fi interface), interface: en0[802.11], ipv4, dns, uses wifi}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask &lt;0568A3A0-A40C-42A8-9491-2FC52D71EFFF&gt;.&lt;4&gt;, _NSURLErrorRelatedURLSessionTaskErrorKey=( "LocalDataTask &lt;0568A3A0-A40C-42A8-9491-2FC52D71EFFF&gt;.&lt;4&gt;" ), NSLocalizedDescription=似乎已断开与互联网的连接。, NSErrorFailingURLStringKey=https://sharkserver.dypc.top/shark_user/login, NSErrorFailingURLKey=https://sharkserver.dypc.top/shark_user/login, _kCFStreamErrorDomainKey=1} 请求失败：似乎已断开与互联网的连接。 以下是问题的具体描述 我的A手机（15pro max 版本18,6,1） 使用xcode直接在A手机上运行我的程序 尝试发起post请求的时候得到了该报错。 我做了以下尝试 1.检查了A手机网络，一切正常，浏览器和其他app均可正常访问网络 2.检查了A手机上我的app权限，确认我因为为我的程序打开了无线网络和蜂窝流量 3.重启A手机，还原A手机网络设置，还原A手机所有设置，重启mac电脑 以上做法均无效，依旧报上面的错误 4.然后我尝试使用B手机(iPhone13 版本18.5)安装该程序 ，B手机可以正常运行并成功发起post请求，证明我的代码没有问题 5.我将代码上传至testfight 然后使用A手机下载testfight里的该程序 ，程序可以成功发起post请求没有任何错误，我再次使用xcode运行该程序到真机，又得到了Code=-1009错误 无法发起post请求

Our goal is to establish a Wi‑Fi Aware data path (NDP) between Apple and Android devices. Apple will act as the Publisher, and Android will act as the Subscriber. Apple-to-Android pairing has already been completed. The Android device can be normally displayed on the Apple official Wi-Fi Aware Sample. However, the indicator is not green. During pairing, the Apple log shows: state: authenticated, and the Android side triggers the callback onPairingSetupSucceeded. During pairing verification, the Apple log shows: state: authenticated, and the Android side triggers the callback onPairingVerificationSucceed. The Android side sends an NDP request to Apple (as shown in the figure 1), but Apple does not reply. Note: Qualcomm’s NDI and NMI are different. In addition, after Apple-to-Apple pairing is completed, the paired device will be recorded in “Settings → Privacy &amp; Security → Paired Devices”. However, after Android-to-Apple pairing is completed, the device is not saved to this list. My iPhone model: iPhone 13, iOS 26.0 (23A5287g).

After Apple-to-Apple pairing is completed, the paired device will be recorded in “Settings → Privacy &amp; Security → Paired Devices”. However, after Android-to-Apple pairing is completed, the device is not saved to this list. Android device can be normally displayed on the Apple official Wi-Fi Aware Sample. However, the indicator is not green. During pairing, the Apple log shows: state: authenticated, and the Android side triggers the callback onPairingSetupSucceeded. During pairing verification, the Apple log shows: state: authenticated, and the Android side triggers the callback onPairingVerificationSucceed. My iPhone is iPhone 13， iOS 26.0 （23A5287g）

This is a major issue. After my iPhone 12 Pro was upgraded to iOS 26 beta 6, Apple's official Wi-Fi Aware Sample APP crashed immediately and couldn't be opened. It just force closes. Has any developer encountered this problem?

We are experiencing an issue with Safari in all versions from 18.0 to 18.5 that does not occur in version 17. It affects both iPhones and Macs. And does not happen in Chrome or Windows. The problem is impacting our customers, and our monitoring tools show a dramatic increase in error volume as more users buy/upgrade to iOS 18. The issue relates to network connectivity that is lost randomly. I can reliably reproduce the issue online in production, as well as on my local development environment. For example our website backoffice has a ping, that has a frequency of X seconds, or when user is doing actions like add to a cart increasing the quantity that requires backend validation with some specific frequency the issue is noticable... To test this I ran a JS code to simulate a ping with a timer that calls a local-dev API (a probe that waits 2s to simulate "work") and delay the next HTTP requests with a dynamic value to simulate network conditions: Note: To even make the issue more clear, I'm using GET with application/json payload to make the request not simple, and require a Pre-flight request, which doubles the issue. (async () =&gt; { for (let i = 0; i &lt; 30; i++) { try { console.log(`Request start ${i} ${new Date().toLocaleString()}`); const res = await fetch(`https://api.redated.com:8090/1/*****/probe?`, { method: 'GET', mode: "cors", //headers: {'Content-Type': 'text/plain'}, headers: { 'Content-Type': 'application/json' }, }); console.log(`Request end ${i} ${new Date().toLocaleString()} status:`, res.status); } catch (err) { console.error(`Request ${i} ${new Date().toLocaleString()} error:`, err); } let delta = Math.floor(Math.random() * 10); console.log("wait delta",delta); await new Promise(r =&gt; setTimeout(r, 1000 - delta)); } })(); For simplicity lets see a case where it fails 1 time only out of 10 requests. (Adjusting the "delta" var on the time interval create more or less errors...) This are the results: The network connection was lost error, which is false, since this is on my localhost machine, but this happens many times and is very reproducible in local and production online. The dev-tools and network tab shows empty for status error, ip, connection_id etc.. its like the request is being terminated very soon. Later I did a detailed debugging with safari and wireshark to really nail down the network flow of the problem: I will explain what this means: Frame 10824 – 18:52:03.939197: new connection initiated (SYN, ACK, ECE). Frame 10831 – 18:52:04.061531: Client sends payload (preflight request) to the server. Frame 10959 – 18:52:09.207686: Server responds with data to (preflight response) to the client. Frame 10960 – 18:52:09.207856: Client acknowledges (ACK) receipt of the preflight response. Frame 10961 – 18:52:09.212188: Client sends the actual request payload after preflight OK and then server replies with ACK. Frame 11092 – 18:52:14.332951: Server sends the final payload (main request response) to the client. Frame 11093 – 18:52:14.333093: captures the client acknowledging the final server response, which marks the successful completion of the main request. Frame 11146 – 18:52:15.348433: [IMPORTANT] the client attempts to send another new request just one second later, which is extremely close to the keep-alive timeout of 1 second. The last message from the server was at 18:52:14.332951, meaning the connection’s keep-alive timeout is predicted to end around 18:52:15.332951 but it does not. The new request is sent at 18:52:15.348433, just microseconds after the predicted timeout. The request leaves before the client browser knows the connection is closed, but by the time it arrives at the server, the connection is already dead. Frame 11147 – 18:52:15.356910: Shows the server finally sending the FIN,ACK to indicate the connection is closed. This happens slightly later than the predicted time, at microsecond 356910 compared to the expected 332951. The FIN,ACK corresponds to sequence 1193 from the ACK of the last data packet in frame 11093. Conclusions: The root cause is related to network handling issues, when the server runs in a setting of keep-alive behavior and keep-alive timeout (in this case 1s) and network timming issue with Safari reusing a closed connection without retrying. In this situation the browser should retry the request, which is what other browsers do and what Safari did before version 18, since it did not suffer from this issue. This behaviour must differ from previous Safari versions (however i read all the public change logs and could not related the regression change). Also is more pronounced with HTTP/1.1 connections due to how the keep-alive is handled. When the server is configured with a short keep-alive timeout of 1 second, and requests are sent at roughly one-second intervals, such as API pings at fixed intervals or user actions like incrementing a cart quantity that trigger backend calls where the probability of failure is high. This effect is even more apparent when the request uses a preflight with POST because it doubles the chance, although GET requests are also affected. This was a just a test case, but in real production our monitoring tools started to detect a big increment with this network error at scale, many requests per day... which is very disrupting, because user actions are randomly being dropped when the user actions and timming happens to be just near a previous connection, where keep alive timeout kicks-in, but because the browser is not yet notified it re-uses the same connection, but by the time it arrived the server is a dead connection. The safari just does nothing about it, does not even retry, be it a pre-flight or not, it just gives this error. Other browsers don't have this issue. Thanks!

Hello, I am new to App development, so I am looking for some advice. I want to develop an app for iPhone, which downloads files (pdf, jpg)from a server to the local storage. I also want to get data from the server to be used in my app. This could be a database access or just simple xml files. I want a secure access based on userid and password. Since in a later version, my app should also run on Android Phones, I am reluctant to use iCloud. I was thinking sftp, but that does not seem to be supported for iOS.

Hello, I am currently investigating if we can disable usage of QUIC on application level. I know we can set enable_quic from /Library/Preferences/com.apple.networkd.plist to false but it will have a global impact since this is a system file, all the applications on machine will stop using QUIC. I don't want that. What i am looking for is to disable QUIC only for my application. Is there any way i can modify URLSession object in my application and disable QUIC? or modify URLSessionConfiguration so system will not use QUIC?

I am trying to setup remote Java debugging between two machines running macOS (15.6 and 26). I am able to get the Java program to listen on a socket. However, I can connect to that socket only from the same machine, not from another machine on my local network. I use nc to test the connection. It reports Connection refused when trying to connect from the other machine. This issue sounds like it could be caused by the Java program lacking Local Network system permission. I am familiar with that issue arising when a program attempts to connect to a port on the local network. In that case, a dialog is displayed and System Settings can be used to grant Local Network permission to the client program. I don't know whether the same permission is required on the program that is receiving client requests. If it is, then I don't know how to grant that permission. There is no dialog, and System Settings does not provide any obvious way to grant permission to a program that I specify. Note that a Java application is a program run by the java command, not a bundled application. The java command contains a hard-wired Info.plist which, annoyingly, requests permission to use the microphone, but not Local Network access.