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Explore the networking protocols and technologies used by the device to connect to Wi-Fi networks, Bluetooth devices, and cellular data services.

Networking Documentation

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URLSessionConfiguration to set usesClassicLoadingMode as false
When i try to set the value ‘false’ for ‘usesClassicLoadingMode’ it is getting crashed. The crash logs has been shared below Ex: let config = URLSessionConfiguration.default if #available(iOS 18.4, *) { config.usesClassicLoadingMode = false } Error log : *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFBoolean objectForKeyedSubscript:]: unrecognized selector sent to instance 0x1f655c390' *** First throw call stack: (0x188ae52ec 0x185f69a7c 0x188b4f67c 0x1889fcb84 0x1889fc4f0 0x191393bc8 0x1889ec8a0 0x1889ec6e4 0x191393ad0 0x191344dac 0x191344b58 0x107cfa064 0x107ce36d0 0x191343fcc 0x1891b3b18 0x1892dae58 0x189235c60 0x18921e270 0x18921d77c 0x18921a8ac 0x107ce0584 0x107cfa064 0x107ce891c 0x107ce95d8 0x107ceabcc 0x107cf5894 0x107cf4eb0 0x212f51660 0x212f4e9f8) terminating due to uncaught exception of type NSException Can you please provider the resolution steps
14
0
303
Apr ’25
Network Push Provider Wifi Selection Behavior
In our App, we have a network extension with a NEAppPushProvider subclass running. We run the following steps Setup a dual-band wireless router per the following: Broadcasting 2.4 GHz and 5 GHz channels Same SSID names for both channels Connected to the production network to the router DHCP assigning addresses in the 10.1.x.x network Connect the mobile device to the 5 GHz network (if needed, turn off the 2.4 GHz network temporarily; once the device connects to the 5 GHz network, the 2.4 GHz network can be turned back on). Create a NEAppPushManager in the App, using the SSID from the above mentioned network and set it to the matchSSIDs property. Call saveToPreferences() on the push manager to save. A. We have UI that shows the extension has been started and it has connected to the server successfully. Walk out of the range of the 5 GHz channel of the router, but stay within range of the 2.4ghz channel. Wait for the mobile device to connect to the 2.4 GHz channel. Expected: The extension would reconnect to the 2.4ghz network. Observed: The extension does not reconnect. Checking the logs for the extension we see that the following was called in the push provider subclass. stop(with:completionHandler:) > PID: 808 | 🗒️🛑 Stopped with reason 3: "noNetworkAvailable" The expectation is that start() on the NEAppPushProvider subclass would be called. Is this an incorrect expectation? How does the NEAppPushProvider handle same network SSID roaming among various band frequencies? I looked at the documentation and did not find any settings targeting 2.4 or 5 ghz networks. Please advise on what to do.
5
1
118
Apr ’25
On-demand rules
I've implemented a custom system extension VPN for macOS using Packet Tunnel Provider. The VPN is configured with on-demand, and a rule to always connect whenever there's traffic: onDemandRules = [NEOnDemandRuleConnect()] As expected, if the VPN isn't active, all traffic gets blocked until it is ready. Not expected: In the following scenario, there is some 'traffic leak': Use only WiFi (not wired cable) Connect the VPN Disable the WiFi and wait for the VPN to disconnect Enable the WiFi Some packets are routed outside the VPN, and aren't being blocked Some moments after, all traffic will be blocked, and the VPN will start the 'connecting' process. Is the above scenario a 'known' issue? Can it be a race condition in the OS, where some packets can be sent after the network is brought back before the VPN process starts? Is there any way to fix this problem? P.S: I'm not using flags such as 'capture all network'
3
1
115
Apr ’25
No internet connection on per-app VPN.
I'm developing a per-app VPN iOS app with Wireguard. For that, I created a configuration file with payload type "com.apple.vpn.managed.applayer". Using the MDM server I installed some apps which need to use the VPN connection. But when I open these apps, I could see the VPN getting enabled in the device. The VPN icon appears on the notification bar but no internet connection. The VPN and internet is working correctly if I change the payload type to "com.apple.vpn.managed" in configuration file.
2
1
421
Mar ’25
peer-to-peer networking for iOS, iPadOS, watchOS, tvOS
Our product (rockhawk.ca) uses the Multipeer Connectivity framework for peer-to-peer communication between multiple iOS/iPadOS devices. My understanding is that MC framework communicates via three methods: 1) infrastructure wifi (i.e. multiple iOS/iPadOS devices are connected to the same wifi network), 2) peer-to-peer wifi, or 3) Bluetooth. In my experience, I don't believe I've seen MC use Bluetooth. With wifi turned off on the devices, and Bluetooth turned on, no connection is established. With wifi on and Bluetooth off, MC works and I presume either infrastructure wifi (if available) or peer-to-peer wifi are used. I'm trying to overcome two issues: Over time (since iOS 9.x), the radio transmit strength for MC over peer-to-peer wifi has decreased to the point that range is unacceptable for our use case. We need at least 150 feet range. We would like to extend this support to watchOS and the MC framework is not available. Regarding #1, I'd like to confirm that if infrastructure wifi is available, MC uses it. If infrastructure wifi is not available, MC uses peer-to-peer wifi. If this is true, then we can assure our customers that if infrastructure wifi is available at the venue, then with all devices connected to it, range will be adequate. If infrastructure wifi is not available at the venue, perhaps a mobile wifi router (battery operated) could be set up, devices connected to it, then range would be adequate. We are about to test this. Reasonable? Can we be assured that if infrastructure wifi is available, MC uses it? Regarding #2, given we are targeting minimum watchOS 7.0, would the available networking APIs and frameworks be adequate to implement our own equivalent of the MC framework so our app on iOS/iPadOS and watchOS devices could communicate? How much work? Where would I start? I'm new to implementing networking but experienced in using the MC framework. I'm assuming that I would write the networking code to use infrastructure wifi to achieve acceptable range. Many thanks! Tim
7
0
1.5k
Sep ’25
SSL certificate failure
This problem doesn’t appear to relate to the app as everything worked when using http (although an https setup issue may still be the problem). The problem appears to relate to the SSL server certificate on the Ubuntu server and the fact that apple does not accept that it is secure. However I have no problem with the equivalent Android app or web browser connections to the same rest API web services. There are numerous posts on these problems on Apple and other Forums, but none have helped me successfully address the issue. I ran an SSL server test on https://www.ssllabs.com/ssltest/ which gives ratings for SSL sites. The test gave an A rating although a number of minor issues were shown that may be crucial to the iOS failure. Some Sectigo certificates said self signed, which I couldn't understand. Error message from XCode log attached 2025-09-10 10:28:01.725091+0100 locateandclock[2291:1585213] ATS failed system trust 2025-09-10 10:28:01.725192+0100 locateandclock[2291:1585213] Connection 1: system TLS Trust evaluation failed(-9802) 2025-09-10 10:28:01.725291+0100 locateandclock[2291:1585213] Connection 1: TLS Trust encountered error 3:-9802 2025-09-10 10:28:01.725352+0100 locateandclock[2291:1585213] Connection 1: encountered error(3:-9802) 2025-09-10 10:28:01.726727+0100 locateandclock[2291:1585213] Task <4E41098F-6B71-4FB8-8753-78DD32961812>.<1> HTTP load failed, 0/0 bytes (error code: -1200 [3:-9802]) 2025-09-10 10:28:01.736504+0100 locateandclock[2291:1585213] Task <4E41098F-6B71-4FB8-8753-78DD32961812>.<1> finished with error [-1200] Error Domain=NSURLErrorDomain Code=-1200 "An SSL error has occurred and a secure connection to the server cannot be made." UserInfo={NSLocalizedRecoverySuggestion=Would you like to connect to the server anyway?, _kCFStreamErrorDomainKey=3, NSErrorPeerCertificateChainKey=( "<cert(0x10681be00) s: *.xxxxxxxxxxx.co.uk i: Sectigo Public Server Authentication CA DV R36>", "<cert(0x10681c800) s: Sectigo Public Server Authentication CA DV R36 i: Sectigo Public Server Authentication Root R46>", "<cert(0x10681d200) s: Sectigo Public Server Authentication Root R46 i: Sectigo Public Server Authentication Root R46>" ), NSErrorClientCertificateStateKey=0, NSErrorFailingURLKey=https://xxxxxxxxxxxx.co.uk/insertclocking, NSErrorFailingURLStringKey=https://xxxxxxxxxxxx.co.uk/insertclocking, NSUnderlyingError=0x282361650 {Error Domain=kCFErrorDomainCFNetwork Code=-1200 "(null)" UserInfo={_kCFStreamPropertySSLClientCertificateState=0, kCFStreamPropertySSLPeerTrust=<SecTrustRef: 0x281cf4460>, _kCFNetworkCFStreamSSLErrorOriginalValue=-9802, _kCFStreamErrorDomainKey=3, _kCFStreamErrorCodeKey=-9802, kCFStreamPropertySSLPeerCertificates=( "<cert(0x10681be00) s: *.xxxxxxxxxxxxxco.uk i: Sectigo Public Server Authentication CA DV R36>", "<cert(0x10681c800) s: Sectigo Public Server Authentication CA DV R36 i: Sectigo Public Server Authentication Root R46>", "<cert(0x10681d200) s: Sectigo Public Server Authentication Root R46 i: Sectigo Public Server Authentication Root R46>" )}}, _NSURLErrorRelatedURLSessionTaskErrorKey=( "LocalDataTask <4E41098F-6B71-4FB8-8753-78DD32961812>.<1>" ), _kCFStreamErrorCodeKey=-9802, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <4E41098F-6B71-4FB8-8753-78DD32961812>.<1>, NSURLErrorFailingURLPeerTrustErrorKey=<SecTrustRef: 0x281cf4460>, NSLocalizedDescription=An SSL error has occurred and a secure connection to the server cannot be made.}
5
0
236
Oct ’25
Autogenerated UI Test Runner Blocked By Local Network Permission Prompt
I've recently updated one of our CI mac mini's to Sequoia in preparation for the transition to Tahoe later this year. Most things seemed to work just fine, however I see this dialog whenever the UI Tests try to run. This application BoostBrowerUITest-Runner is auto-generated by Xcode to launch your application and then run your UI Tests. We do not have any control over it, which is why this is most surprising. I've checked the codesigning identity with codesign -d -vvvv as well as looked at it's Info.plist and indeed the usage descriptions for everything are present (again, this is autogenerated, so I'm not surprised, but just wanted to confirm the string from the dialog was coming from this app) &lt;?xml version="1.0" encoding="UTF-8"?&gt; &lt;!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"&gt; &lt;plist version="1.0"&gt; &lt;dict&gt; &lt;key&gt;BuildMachineOSBuild&lt;/key&gt; &lt;string&gt;22A380021&lt;/string&gt; &lt;key&gt;CFBundleAllowMixedLocalizations&lt;/key&gt; &lt;true/&gt; &lt;key&gt;CFBundleDevelopmentRegion&lt;/key&gt; &lt;string&gt;en&lt;/string&gt; &lt;key&gt;CFBundleExecutable&lt;/key&gt; &lt;string&gt;BoostBrowserUITests-Runner&lt;/string&gt; &lt;key&gt;CFBundleIdentifier&lt;/key&gt; &lt;string&gt;company.thebrowser.Browser2UITests.xctrunner&lt;/string&gt; &lt;key&gt;CFBundleInfoDictionaryVersion&lt;/key&gt; &lt;string&gt;6.0&lt;/string&gt; &lt;key&gt;CFBundleName&lt;/key&gt; &lt;string&gt;BoostBrowserUITests-Runner&lt;/string&gt; &lt;key&gt;CFBundlePackageType&lt;/key&gt; &lt;string&gt;APPL&lt;/string&gt; &lt;key&gt;CFBundleShortVersionString&lt;/key&gt; &lt;string&gt;1.0&lt;/string&gt; &lt;key&gt;CFBundleSignature&lt;/key&gt; &lt;string&gt;????&lt;/string&gt; &lt;key&gt;CFBundleSupportedPlatforms&lt;/key&gt; &lt;array&gt; &lt;string&gt;MacOSX&lt;/string&gt; &lt;/array&gt; &lt;key&gt;CFBundleVersion&lt;/key&gt; &lt;string&gt;1&lt;/string&gt; &lt;key&gt;DTCompiler&lt;/key&gt; &lt;string&gt;com.apple.compilers.llvm.clang.1_0&lt;/string&gt; &lt;key&gt;DTPlatformBuild&lt;/key&gt; &lt;string&gt;24A324&lt;/string&gt; &lt;key&gt;DTPlatformName&lt;/key&gt; &lt;string&gt;macosx&lt;/string&gt; &lt;key&gt;DTPlatformVersion&lt;/key&gt; &lt;string&gt;15.0&lt;/string&gt; &lt;key&gt;DTSDKBuild&lt;/key&gt; &lt;string&gt;24A324&lt;/string&gt; &lt;key&gt;DTSDKName&lt;/key&gt; &lt;string&gt;macosx15.0.internal&lt;/string&gt; &lt;key&gt;DTXcode&lt;/key&gt; &lt;string&gt;1620&lt;/string&gt; &lt;key&gt;DTXcodeBuild&lt;/key&gt; &lt;string&gt;16C5031c&lt;/string&gt; &lt;key&gt;LSBackgroundOnly&lt;/key&gt; &lt;true/&gt; &lt;key&gt;LSMinimumSystemVersion&lt;/key&gt; &lt;string&gt;13.0&lt;/string&gt; &lt;key&gt;NSAppTransportSecurity&lt;/key&gt; &lt;dict&gt; &lt;key&gt;NSAllowsArbitraryLoads&lt;/key&gt; &lt;true/&gt; &lt;/dict&gt; &lt;key&gt;NSAppleEventsUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSBluetoothAlwaysUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSCalendarsUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSCameraUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSContactsUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSDesktopFolderUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSDocumentsFolderUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSDownloadsFolderUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSFileProviderDomainUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSFileProviderPresenceUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSLocalNetworkUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSLocationUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSMicrophoneUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSMotionUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSNetworkVolumesUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSPhotoLibraryUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSRemindersUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSRemovableVolumesUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSSpeechRecognitionUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSSystemAdministrationUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSSystemExtensionUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;OSBundleUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;/dict&gt; &lt;/plist&gt; Additionally, spctl --assess --type execute BoostBrowserUITests-Runner.app return an exit code of 0 so I assume that means it can launch just fine, and applications are allowed to be run from "anywhere" in System Settings. I've found the XCUIProtectedResource.localNetwork value, but it seems to only be accessible on iOS for some reason (FB17829325). I'm trying to figure out why this is happening on this machine so I can either fix our code or fix the machine. I have an Apple script that will allow it, but it's fiddly and I'd prefer to fix this the correct way either with the machine or with fixing our testing code.
9
1
332
Jun ’25
Join Wi-Fi Network from QR Code
I was wondering if anybody knows if it's possible for an app to use a QR code to join a Wi-Fi network - the same functionality as the iOS 11 Camera app?I have some code reading a QR Code that looks something like - "WIFI:S:name-of-network;T:WPA;P:password;;"This QR code works perfectly in the native camera app - asking the user if they'd like to join the Wi-Fi network and successfully joining if they do.When I scan the QR code in my own code, I get the following error: canOpenURL: failed for URL: "WIFI:S:name-of-network;T:WPA;P:password;;" - error: "The operation couldn’t be completed. (OSStatus error -10814.)"In my app, I've got URL Schemes for "prefs" and have added "wifi" in LSApplicationQueriesSchemes.Am I doing something wrong, or is this simply not possible?If it's not possible, is there anyway to use the iOS native camera functionality within an app?
7
0
46k
Jan ’25
Automatic Background File Uploads
I have currently created an app which contains an upload button which when clicked upload health data using HealthKit to an AWS S3 bucket. Now I want to implement an automatic file upload mechanism which would mean that the app is installed and opened just once - and then the upload must happen on a schedule (once daily) from the background without ever having to open the app again. I've tried frameworks like NSURLSession and BackgroundTasks but nothing seems to work. Is this use case even possible to implement? Does iOS allow this? The file is just a few KBs in size. For reference, here is the Background Tasks code: import UIKit import BackgroundTasks import HealthKit class AppDelegate: NSObject, UIApplicationDelegate { let backgroundTaskIdentifier = "com.yourapp.healthdata.upload" func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -&gt; Bool { // Register the background task BGTaskScheduler.shared.register(forTaskWithIdentifier: backgroundTaskIdentifier, using: nil) { task in self.handleHealthDataUpload(task: task as! BGAppRefreshTask) } // Schedule the first upload task scheduleDailyUpload() return true } // Schedule the background task for daily execution func scheduleDailyUpload() { print("[AppDelegate] Scheduling daily background task.") let request = BGAppRefreshTaskRequest(identifier: backgroundTaskIdentifier) request.earliestBeginDate = Date(timeIntervalSinceNow: 24*60*60) do { try BGTaskScheduler.shared.submit(request) print("[AppDelegate] Daily background task scheduled.") } catch { print("[AppDelegate] Could not schedule daily background task: \(error.localizedDescription)") } } // Handle the background task when it's triggered by the system func handleHealthDataUpload(task: BGAppRefreshTask) { print("[AppDelegate] Background task triggered.") // Call your upload function with completion handler HealthStoreManager.shared.fetchAndUploadHealthData { success in if success { print("[AppDelegate] Upload completed successfully.") task.setTaskCompleted(success: true) // Schedule the next day's upload after a successful upload self.scheduleDailyUpload() } else { print("[AppDelegate] Upload failed.") task.setTaskCompleted(success: false) } } // Handle task expiration (e.g., if upload takes too long) task.expirationHandler = { print("[AppDelegate] Background task expired.") task.setTaskCompleted(success: false) } } }
4
0
456
Feb ’25
May be port leak when use handleNewUDPFlow in Network Extension
When handleNewUDPFlow in NETransparentProxyProvider is used to handle UDP data from port 53, at the same time, run the script continuously to execute nslookup or dig, about tens of thousands of times later, the nslookup shows the error "isc_socket_bind: address not available". So I check the system port status, and find all of the ports from 49152 to 65535 are occupied. The number of net.inet.udp.pcbcount is also very high. net.inet.udp.pcbcount: 91433 Then I made the following attempts: handleNewUDPFlow function return false directly, the nslookup script runs with no problems. I write a simple network extension that use handleNewUDPFlow to reply the mock data directly, and only hijack the UDP data from my test program (HelloWorld-5555). My network exntension code: override func handleNewUDPFlow(_ flow: NEAppProxyUDPFlow, initialRemoteEndpoint remoteEndpoint: NWEndpoint) -> Bool { guard let tokenData = flow.metaData.sourceAppAuditToken, tokenData.count == MemoryLayout<audit_token_t>.size else { return false } let audit_token = tokenData.withUnsafeBytes { buf in buf.baseAddress?.assumingMemoryBound(to: audit_token_t.self).pointee } let pid = audit_token_to_pid(audit_token ?? audit_token_t()) if (!flow.metaData.sourceAppSigningIdentifier.starts(with: "HelloWorld-5555")) { return false } Logger.statistics.log("handleNewUDPFlow \(remoteEndpoint.debugDescription, privacy: .public) \(flow.hash), pid:\(pid), \(flow.metaData.sourceAppSigningIdentifier, privacy: .public)") flow.open(withLocalEndpoint: nil) { error in if let error { os_log("flow open error: %@", error.localizedDescription) return } flow.readDatagrams { data_grams, remote_endpoints, read_err in guard let read_data_grams = data_grams, let read_endpoints = remote_endpoints, read_err == nil else { os_log("readDatagrams failed") flow.closeReadWithError(nil) flow.closeWriteWithError(nil) return } let mockData = Data([0x01,0x02,0x03]) let datagrams = [ mockData ] guard let remoteEnd = remoteEndpoint as? NWHostEndpoint else { os_log("Not the NWHostENdpoint") flow.closeReadWithError(nil) flow.closeWriteWithError(nil) return } let endpoints = [ NWHostEndpoint(hostname: remoteEnd.hostname, port: remoteEnd.port) ] flow.writeDatagrams(datagrams, sentBy: endpoints) { error in if let error { os_log("writeDatagrams error: %@", error.localizedDescription) } os_log("writeDatagrams close") flow.closeReadWithError(nil) flow.closeWriteWithError(nil) } } } return true } My test program code: void send_udp() { int sockfd; struct sockaddr_in server_addr; char buffer[BUFFER_SIZE]; int bytes_sent; // create socket if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { perror("socket create failed"); exit(EXIT_FAILURE); } struct sockaddr_in local_addr; memset(&local_addr, 0, sizeof(local_addr)); local_addr.sin_family = AF_INET; local_addr.sin_addr.s_addr = htonl(INADDR_ANY); local_addr.sin_port = htonl(0); // bind if (bind(sockfd, (struct sockaddr*)&local_addr, sizeof(local_addr)) < 0) { printf("IPV4 bind errno:%d\n", errno); close(sockfd); return; } // server addr memset(&server_addr, 0, sizeof(server_addr)); server_addr.sin_family = AF_INET; server_addr.sin_port = htons(SERVER_PORT); server_addr.sin_addr.s_addr = inet_addr(SERVER_IP); // send & recv strcpy(buffer, "Hello, UDP server!"); bytes_sent = sendto(sockfd, buffer, strlen(buffer), 0, (struct sockaddr *)&server_addr, sizeof(server_addr)); if (bytes_sent < 0) { perror("sendto failed"); close(sockfd); exit(EXIT_FAILURE); } printf("sendto ok\n"); char recvbuf[128] = {0}; socklen_t len = sizeof(server_addr); int sz = recvfrom(sockfd, recvbuf, sizeof(recvbuf), MSG_WAITALL, (struct sockaddr *) &server_addr, &len); printf("recv sz: %d\n", sz); close(sockfd); return; } int main() { send_udp(); return 0; } 2.1 When I use bind in my program, after the program running tens of thousands of times, the ports are exhausted, and nslookup return the error "isc_socket_bind: address not available". The case looks like running the nslookup script, because the nslookup will call the bind. 2.2 When I remove the bind from my program, all the tests are go. I have made the above experiments on different systems: 13.x, 14.x, 15.x, and read the kernel source code about bind and port assignment, bsd/netinet/in_pcb.c bsd/netinet/udp_usrreq.c and find kernel will do different action for network extension by call necp_socket_should_use_flow_divert I have checked my network extension process by lsof and netstat, its sockets or flows are all closed properly. I don't know how I can avoid this problem to ensure my network extension to work long time properly. Apparently, the port exhaustion is related to the use of bind function and network extension. I doubt there is a port leak problem in system when use network extension. Hope for your help.
3
0
885
Mar ’25
Don't fragment bit doesn't get set in Sequoia
Hi, I've noticed a weird behavior happening on Sequoia with DF bit: On machine where SIP is disabled, when I do /sbin/ping -D -s 1400 8.8.8.8 I do see the DF bit in wireshark On machine where SIP is enabled, when I do /sbin/ping -D -s 1400 8.8.8.8 I do not see the DF bit in wireshark The -D flag should set the DF bit but for some reason it doesn’t if the SIP is enabled. Perhaps there was any change in permission/entitlements mechanism in Sequoia that can explain it ? I'm using the built-in ping command so maybe it should be signed with more entitlements ?
3
0
357
Mar ’25
Can NETunnelProviderManager.protocolConfiguration be changed on the fly?
I am learning about layer 3 VPN implementations for MacOS, and am slowly making my way through docs and tutorials. I noticed that part of creating an instance of NETunnelProviderManager on the app side of the project requires the specification of protocolConfiguration via an instance of NETunnelProviderProtocol. One of the arguments for this class is serverAdress, which to my understanding, tells the OS where to route traffic towards at the end of the day. My question: many VPNs these days allow the option to specify the location for which you want your traffic to be routed through. I imagine this would necessitate changing this serverAddress field in the backend. However, setting this option (on a commercially available VPN) doesn't typically prompt the OS notification that you get when initially installing a VPN configuration for the first time. How is this functionality achieved? I could see one possible solution being that most VPN providers route through a main service beforehand (so the first IP in the chain never has to change), though I could see this being problematic for a number of other reasons. Assuming you have a valid NETunnelProviderManager object called manager, is this valid? self.manager?.protocolConfiguration?.serverAddress = "somewhereElse" Even if it compiles, will the traffic be properly re-routed? My understanding of the flow right now is that in order to "lock in" a new configuration, or modify it, you need to call manager.saveToPreferences, which triggers the OS notification I mentioned earlier.
1
0
290
Feb ’25
Content Filter Providers in unsupervised and unmanaged iOS devices
I'm looking at implementing an iOS app that has includes a Content Filter Provider to block access to certain domains when accessed on the device. This uses NEFilterManager, NEFilterDataProvider and NEFilterControlProvider to handle configuration and manage the network flows and block as necessary. My question is can you deploy this in an iOS 18+ app on the App Store to devices which are unmanaged, unsupervised and don't use Screen Time APIs? Although not 100% clear, this technote seems to say it is not possible: https://developer.apple.com/documentation/Technotes/tn3134-network-extension-provider-deployment Testing this on a Developer device and build works successfully without any MDM profiles installed. A similar approach using the same APIs also works on macOS once user permissions have been given. If it can't work on unsupervised, unmanaged iOS devices, is possible for the user to first manually install a MDM profile which includes the required 'Content Filter' details and then have it work? If not, how would you filter iOS network traffic on an unmanaged, unsupervised device? Is it necessary to use a VPN or DNS approach instead (which may be a lot less privacy compliant)?
6
0
408
Feb ’25
DNS not working when VPN is active on iOS/iPadOS 18.x
Our company has a VPN client that uses the Packet Tunnel Provider network extension and when 18 came out we noticed that we were no longer seeing DNS requests get sent to the VPNs TUN interface. Do a packet trace, once the VPN becomes active we see requests to _dns.resolver.arpa and 12-courier.push.apple.com, which both get resolved as expected. Also our main app that controls the VPN service and does authentication has to resolve a hostname to get to an authentication service and we see those requests just fine as well. However, when we try to resolve by going to a webpage in Safari we see no DNS request corresponding to that. What are we missing? At first I thought it was the RFC9461 stuff but from the packet traces I don't believe that is the case. I have also tried other networking tools to send the DNS requests and that failed as well.
4
0
388
Dec ’24
Will an iPhone reconnect automatically to a wifi network we connected to previously with joinOnce = false?
PLATFORM AND VERSION: iOS Development environment: Xcode 15.3, macOS 14.7.1 (23H222) Run-time configuration: iOS 18.3.1 DESCRIPTION OF PROBLEM: Our app uses NEHotspotConfigurationManager with joinOnce set to false to connect to an IoT device's Wi-Fi hotspot. Later, we programmatically disconnect from this hotspot. We are wondering if, after this programmatic disconnection, there is a possibility that the iPhone will automatically reconnect to the hotspot (even when our app is not running). Does it matter if the hotspot's SSID is hidden or not? This concern arises because the iPhone is already familiar with the hotspot's network configuration. Our testing indicates that this does not happen, but we want to be certain. This is a behavior we do NOT want to occur. We set joinOnce to false because we experience connectivity issues with the IoT device when joinOnce is true (there are several discussions in forums regarding issues with setting it to true). Thank you. Thanks.
5
0
366
Mar ’25