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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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Reduced certificate lifespan: CA root
I have some concerns related to shortening the lifetime of certificates, as per https://support.apple.com/en-gb/102028 Does this apply to Private CA root certificates? And if yes: does it apply if I use ATS and higher level API like URLSession does it apply it I carry my root CA cert in my app payload and use low level libraries without ATS support?
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Feb ’25
Expected behavior of searchDomains
Based on https://developer.apple.com/documentation/networkextension/nednssettings/searchdomains , we expect the values mentioned in searchDomains to be appended to a single label DNS query. However, we are not seeing this behavior. We have a packetTunnelProvider VPN, where we set searchDomains to a dns suffix (for ex: test.com) and we set matchDomains to applications and suffix (for ex: abc.com and test.com) . When a user tries to access https://myapp , we expect to see a DNS query packet for myapp.test.com . However, this is not happening when matchDomainsNoSearch is set to true. https://developer.apple.com/documentation/networkextension/nednssettings/matchdomainsnosearch When matchDomainsNoSearch is set to false, we see dns queries for myapp.test.com and myapp.abc.com. What is the expected behavior of searchDomains?
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8h
Apps do not trigger pop-up asking for permission to access local network on macOS Sequoia/Tahoe
We are having an issue with the Local Network permission pop-up not getting triggered for our apps that need to communicate with devices via local network interfaces/addresses. As we understand, apps using UDP should trigger this, causing macOS to prompt for access, or, if denied, fail to connect. However, we are facing issues with macOS not prompting this popup at all. Here are important and related points: Our application is packaged as a .app package and distributed independently (not on the App Store). The application controls hardware that we manufacture. In order to find the hardware on the network, we send a UDP broadcast with a message for our hardware on the local network, and the hardware responds with a message back. However, the popup (to ask for permission) never shows up. The application is not able to find the hardware device. It is interesting to note that data is still sent out to the network (without the popup) but we receive back the wrong data. The behaviour is consistent macOS Sequoia (and above) with both Apple And Intel silicon. Workarounds that have been tried: Manual Authorization: One solution suggested in various blogs was to go to "Settings → Privacy and Security-> Local network", find your application and grant access. However, the application never shows up in the list here. Firewall: No difference is seen in behaviour with firewall being ON OR OFF. Setting NSLocalNetworkUsageDescription: We have also tried setting the Info.plist adding the NSLocalNetworkUsageDescription with a meaningful string and updating the NSBonjourServices. Running Via terminal (WORKS): Running the application via terminal sees no issues. The application runs correctly and is able to send UDP and receive correct data (and find the devices on the network). But this is not an appropriate solution. How can we get this bug/issue fixed in macOS Sequoia (and above)? Are there any other solutions/workarounds that we can try on our end?
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13h
Replacing Packet Filter (pf) with Content Filter for VPN Firewall Use Case
Hi, We're in the process of following Apple’s guidance on transitioning away from Packet Filter (pf) and migrating to a Network Extension-based solution that functions as a firewall. During this transition, we've encountered several limitations with the current Content Filter API and wanted to share our findings. Our VPN client relies on firewall functionality to enforce strict adherence to split tunneling rules defined via the routing table. This ensures that no traffic leaks outside the VPN tunnel, which is critical for our users for a variety of reasons. To enforce this, our product currently uses interface-scoped rules to block all non-VPN traffic outside the tunnel. Replicating this behavior with the Content Filter API (NEFilterDataProvider) appears to be infeasible today. The key limitation we've encountered is that the current Content Filter API does not expose information about the network interface associated with a flow. As a workaround, we considered using the flow’s local endpoint IP to infer the interface, but this data is not available until after returning a verdict to peek into the flow’s data—at which point the connection has already been established. This can result in connection metadata leaking outside the tunnel, which may contain sensitive information depending on the connection. What is the recommended approach for this use case? NEFilterPacketProvider? This may work, but it has a negative impact on network performance. Using a Packet Tunnel Provider and purely relying on enforceRoutes? Would this indeed ensure that no traffic can leak by targeting a specific interface or by using a second VPN extension? And more broadly—especially if no such approach is currently feasible with the existing APIs—we're interpreting TN3165 as a signal that pf should be considered deprecated and may not be available in the next major macOS release. Is that a reasonable interpretation?
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May ’25
URLSessionDownloadTaskDelegate functions not called when using URLSession.download(for:), but works when using URLSession.downloadTask(with:)
I'm struggling to understand why the async-await version of URLSession download task APIs do not call the delegate functions, whereas the old non-async version that returns a reference to the download task works just fine. Here is my sample code: class DownloadDelegate: NSObject, URLSessionDownloadDelegate { func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) { // This only prints the percentage of the download progress. let calculatedProgress = Float(totalBytesWritten) / Float(totalBytesExpectedToWrite) let formatter = NumberFormatter() formatter.numberStyle = .percent print(formatter.string(from: NSNumber(value: calculatedProgress))!) } } // Here's the VC. final class DownloadsViewController: UIViewController { private let url = URL(string: "https://pixabay.com/get/g0b9fa2936ff6a5078ea607398665e8151fc0c10df7db5c093e543314b883755ecd43eda2b7b5178a7e613a35541be6486885fb4a55d0777ba949aedccc807d8c_1280.jpg")! private let delegate = DownloadDelegate() private lazy var session = URLSession(configuration: .default, delegate: delegate, delegateQueue: nil) // for the async-await version private var task: Task<Void, Never>? // for the old version private var downloadTask: URLSessionDownloadTask? override func viewWillAppear(_ animated: Bool) { super.viewWillAppear(animated) task?.cancel() task = nil task = Task { let (_, _) = try! await session.download(for: URLRequest(url: url)) self.task = nil } // If I uncomment this, the progress listener delegate function above is called. // downloadTask?.cancel() // downloadTask = nil // downloadTask = session.downloadTask(with: URLRequest(url: url)) // downloadTask?.resume() } } What am I missing here?
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2.1k
May ’25
Network System Extension cannot use network interface of another VPN
Hi, Our project is a MacOS SwiftUI GUI application that bundles a (Sandboxed) System Network Extension, signed with a Developer ID certificate for distribution outside of the app store. The system network extension is used to write a packet tunnel provider (NEPacketTunnelProvider), as our project requires the creation of a TUN device. In order for our System VPN to function, it must reach out to a (self-hosted) server (i.e. to discover a list of peers). Being self-hosted, this server is typically not accessible via the public web, and may only be accessible from within a VPN (such as those also implemented using NEPacketTunnelProvider, e.g. Tailscale, Cloudflare WARP). What we've discovered is that the networking code of the System Network Extension process does not attempt to use the other VPN network interfaces (utunX) on the system. In practice, this means requests to IPs and hostnames that should be routed to those interfaces time out. Identical requests made outside of the Network System Extension process use those interfaces and succeed. The simplest example is where we create a URLSession.downloadTask for a resource on the server. A more complicated example is where we execute a Go .dylib that continues to communicate with that server. Both types of requests time out. Two noteworthy logs appear when packets fail to send, both from the kernel 'process': cfil_hash_entry_log:6088 <CFIL: Error: sosend_reinject() failed>: [30685 com.coder.Coder-Desktop.VPN] <UDP(17) out so b795d11aca7c26bf 57728068503033955 57728068503033955 age 0> lport 3001 fport 3001 laddr 100.108.7.40 faddr 100.112.177.88 hash 58B15863 cfil_service_inject_queue:4472 CFIL: sosend() failed 49 I also wrote some test code that probes using a UDP NWConnection and NWPath availableInterfaces. When run from the GUI App, multiple interfaces are returned, including the one that routes the address, utun5. When ran from within the sysex, only en0 is returned. I understand routing a VPN through another is unconventional, but we unfortunately do need this functionality one way or another. Is there any way to modify which interfaces are exposed to the sysex? Additionally, are these limitations of networking within a Network System Extension documented anywhere? Do you have any ideas why this specific limitation might exist?
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Jul ’25
Need Inputs on Which Extension to Use
Hi all, I have a working macOS (Intel) system extension app that currently uses only a Content Filter (NEFilterDataProvider). I need to capture/log HTTP and HTTPS traffic in plain text, and I understand NETransparentProxyProvider is the right extension type for that. For HTTPS I will need TLS inspection / a MITM proxy — I’m new to that and unsure how complex it will be. For DNS data (in plain text), can I use the same extension, or do I need a separate extension type such as NEPacketTunnelProvider, NEFilterPacketProvider, or NEDNSProxyProvider? Current architecture: Two Xcode targets: MainApp and a SystemExtension target. The SystemExtension target contains multiple network extension types. MainApp ↔ SystemExtension communicate via a bidirectional NSXPC connection. I can already enable two extensions (Content Filter and TransparentProxy). With the NETransparentProxy, I still need to implement HTTPS capture. Questions I’d appreciate help with: Can NETransparentProxy capture the DNS fields I need (dns_hostname, dns_query_type, dns_response_code, dns_answer_number, etc.), or do I need an additional extension type to capture DNS in plain text? If a separate extension is required, is it possible or problematic to include that extension type (Packet Tunnel / DNS Proxy / etc.) in the same SystemExtension Xcode target as the TransparentProxy? Any recommended resources or guidance on TLS inspection / MITM proxy setup for capturing HTTPS logs? There are multiple DNS transport types — am I correct that capturing DNS over UDP (port 53) is not necessarily sufficient? Which DNS types should I plan to handle? I’ve read that TransparentProxy and other extension types (e.g., Packet Tunnel) cannot coexist in the same Xcode target. Is that true? Best approach for delivering logs from multiple extensions to the main app (is it feasible)? Or what’s the best way to capture logs so an external/independent process (or C/C++ daemon) can consume them? Required data to capture (not limited to): All HTTP/HTTPS (request, body, URL, response, etc.) DNS fields: dns_hostname, dns_query_type, dns_response_code, dns_answer_number, and other DNS data — all in plain text. I’ve read various resources but remain unclear which extension(s) to use and whether multiple extension types can be combined in one Xcode target. Please ask if you need more details. Thank you.
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Network Extension - On shutdown Xsan can't unmount and cause a crash when NEFilterProvider is enabled
Hey, We also opened a feedback assistant request, and also opened a ticket with Apple Developer Technical Support a while ago that notice the unmount problem also but it was before we pin point the problem to the Network Extension. After a further investigation, we've found out that the root cause of this problem is cause by having a network filter from the NetworkExtension provider on (Specifically we have tested with the NEFilterDataProvider) while having a Xsan volume. The NEFilterDataProvider causing problems for the Xsan, and is stalling the shutdown until we get a panic from watchdog timeout, and only then the mac is fully shutdown. The problem from what we investigated and also talked with you, is that the Xsan process can't unmount the volume and stuck. We have also noticed that if we install a network extension and allow the popup of the network filters, i.e enabled the NEFilterDataProvider the computer is stuck, and the finder is in a non responsive state until a reboot (Also probably due to the fact the Xsan is now in a problematic state). This tests was done on latest versions of MacOs 13 & 14. We have taken a sysdiagnose from the computer while we have tested. Do you familiar with the problem (We got no answer on the feedback assistant)? Thank you, Idan
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Sep ’25
IOS App tcp connect and local network permission
Recently, my application was having trouble connecting socket using TCP protocol after it was reinstalled. The cause of the problem was initially that I did not grant local network permissions when I reinstalled, I was aware of the problem, so socket connect interface worked fine after I granted permissions. However, the next time I repeat the previous operation, I also do not grant local network permissions, and then turn it back on in the Settings, and socket connect interfcae does not work properly (connect interface return errno 65, the system version and code have not changed). Fortunately, socket connect success after rebooting the phone, and more importantly, I was able to repeat the problem many times. So I want to know if the process between when I re-uninstall the app and deny local network permissions, and when I turn it back on in Settings, is that permissions have been granted normally, and not fake, and not required a reboot to reset something for socket coonnect to take effect.
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Jun ’25
[networkextesion] dnsproxy
hello I am testing the use of network extension. When we use dnsproxy to proxy DNS requests, we will send you a message that the udp pcbcount of your system continues to increase. For example for ((i=1; i<=99999; i++));do echo "Attempt $i:" dig google.com done when the dig command is used continuously, the dig command will show the following errors when pcbcount reaches a certain number. isc_socket_bind: address not available Can you help us determine what the problem might be? thank you
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Feb ’25
Network extension doesn't get the updated preferred language after changing phone language
We’ve noticed an issue where after running a network extension, if the phone’s language is changed the Locale.preferredLanguages array is not updated and still returns the old array. It only returns the updated array when the app is reinstalled or the phone is restarted. This is unlike the app itself where using the same Locale.preferredLanguages API immediately returns the updated array. We think this issue is also the cause of notifications that are sent by the network extension being in the previous language as long as the app isn’t reinstalled or the phone is restarted, despite our Localizable file having localised strings for the new language. Feedback ID: FB20086051 The feedback report includes a sample project with steps on how to reproduce the issue.
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Sep ’25
iOS App udp and local network permission
Recently, my application was having trouble sending udp messages after it was reinstalled. The cause of the problem was initially that I did not grant local network permissions when I reinstalled, I was aware of the problem, so udp worked fine after I granted permissions. However, the next time I repeat the previous operation, I also do not grant local network permissions, and then turn it back on in the Settings, and udp does not work properly (no messages can be sent, the system version and code have not changed). Fortunately, udp worked after rebooting the phone, and more importantly, I was able to repeat the problem many times. So I want to know if the process between when I re-uninstall the app and deny local network permissions, and when I turn it back on in Settings, is that permissions have been granted normally, and not fake, and not required a reboot to reset something for udp to take effect. I'm not sure if it's the system, or if it's a similar situation as described here, hopefully that will help me find out
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1.4k
Jun ’25
DNSServiceBrowse() callback receives error code -65570
Hi, I am trying to update an old prototype I made for tvOS using DNSServiceBrowse(). The target was tvOS 17. My old build from September 2023 still works fine: It can discover computers on the same local network as the Apple TV (simulator). However, now that I am using Xcode 16, the DNSServiceBrowse() callback (of type DNSServiceBrowseReply) receives the error code: -65570. The call to DNSServiceBrowse() itself returns no error, neither does the following call to DNSServiceProcessResult() — which actually triggers the call of the callback. I found nowhere in the Internet any list of possible error codes received by the callback, so I have no idea what it means. So, my first question is: What does this error code mean? (And is there any list of the possible errors somewehere, with their meaning?) Since it was a prototype, I have no provisioning profile defined for it. Could that be related to the issue? Since I will make a real app out that prototype (targeting tvOS 18), I will have to define a provisioning profile for it. Would a provisioning profile for the app solve the issue? If yes, are there any requirements for that profile that I should take into account to solve the issue? Thank you in advance for any help, Marc
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Jun ’25
adhoc ipa, installed on iOS 18 devices, udp and tcp cannot access the local network, such as 17.25.11.128
I have read all the information and forum posts about local network, such as TN3179, etc., and have added NSLocalNetworkUsageDescription, but it does not solve my problem. The problem I encountered is described as follows: Device: iOS18.1.1 Signing method: automatic Xcode debug directly runs, and the app can access 17.25.11.128 normally. However, relase run or packaged into adhoc installation, this IP cannot be accessed. There is a phenomenon that the app package of the App Store can also be used. Our test team has few iOS18+ devices, and internal testing is not possible. Please contact us as soon as possible, thank you. ======= 我已经了解了所有关于local network 相关的资料和论坛帖子,比如TN3179 等等, 已经添加了 NSLocalNetworkUsageDescription, 但是不解决我的问题。 我遇到的问题描述如下: 设备:iOS18.1.1 签名方式:自动 xcode debug 直接运行,app是可以正常访问17.25.11.128的。 但是 relase run 或者 打包成 adhoc 安装,就无法访问这个IP了。 有一个现象, App Store 的app包 也是可以的。 我们的测试团队,iOS18+的设备就没几个,还不能内部测试了。请尽快联系我们,谢谢。
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May ’25
URLSession downloadTask(with:) TimeOut Error NSURLErrorDomain Code=-1001, _kCFStreamErrorCodeKey=-2103
I have been battling this intermittent error for some time. It is generally random and has been difficult to reproduce until yesterday when I stumbled across a way to reproduce it each time. I can cause the code to throw this error: Task <70E3909F-8C30-4F34-A8B0-4AF3B41DD81B>.<1> finished with error [-1001] Error Domain=NSURLErrorDomain Code=-1001 "The request timed out." UserInfo={_kCFStreamErrorCodeKey=-2103, _NSURLErrorFailingURLSessionTaskErrorKey=BackgroundDownloadTask <70E3909F-8C30-4F34-A8B0-4AF3B41DD81B>.<1>, _NSURLErrorRelatedURLSessionTaskErrorKey=( "BackgroundDownloadTask <70E3909F-8C30-4F34-A8B0-4AF3B41DD81B>.<1>", "LocalDownloadTask <70E3909F-8C30-4F34-A8B0-4AF3B41DD81B>.<1>" ), NSLocalizedDescription=The request timed out., _kCFStreamErrorDomainKey=4, NSErrorFailingURLStringKey=https://redacted*, NSErrorFailingURLKey=https://redacted*} *"redacted" is the backend URL, and it is the correct and same path for each immediately after restarting an actual device. I have been over the following threads with no results: What is kCFStreamErrorCodeKey=-4 (kCFStreamErrorDomainKey=4) Request timed out with _kCFStreamErrorCodeKey=60 How to better diagnose -1001 "The request timed out." URLSession errors Random timed out error on app start Because I was able to reproduce it, I have been able to get the following logs: Console Logs.txt Last bit of information is that I had Network Instruments running, and when this error occurred, I found that the Connection ID was "No Connection" and it appears the request was never actually sent, though it waited the full time out for a backend response. Any help would be appreciated. This data request is being used after sending a certain APNs to update necessary data in the background, and has been the source of many user complaints.
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998
Feb ’25
macOS VPN apps outside of the App Store
Apple is encouraging VPN apps on macOS to transition to Network Extension APIs, if they haven't done so yet, see: TN3165: Packet Filter is not API WWDC25: Filter and tunnel network traffic with NetworkExtension Using Network Extension is fine for VPN apps that are distributed via the Mac App Store. Users get one pop-up requesting permission to add VPN configurations and that's it. However, VPN apps that are distributed outside of the App Store (using Developer ID) cannot use Network Extension in the same way, such apps need to install a System Extension first (see TN3134: Network Extension provider deployment). Installing a System Extension is a very poor user experience. There is a pop-up informing about a system extension, which the user has to manually enable. The main button is "OK", which only dismisses the pop-up and in such case there is little chance that the user will be able to find the correct place to enable the extension. The other button in that pop-up navigates to the correct screen in System Settings, where the user has to enable a toggle. Then there is a password prompt. Then the user has to close the System Settings and return to the app. This whole dance is not necessary for VPN apps on the Mac App Store, because they work with "app extensions" rather than "system extensions". As a developer of a VPN app that is distributed outside of the App Store, my options are: Implement VPN functionality in an alternative way, without Network Extension. This is discouraged by Apple. Use a System Extension with Network Extension. This is going to discourage my users. I have submitted feedback to Apple: FB19631390. But I wonder, why did Apple create this difference in the first place? Is there a chance that they will either improve the System Extension installation process or even allow "app extensions" outside of the Mac App Store?
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241
Aug ’25
Choosing interface for multicast UDP
Hi all. Title says it all really. I have an app on MacOS that sends multicast UDP to multiple iOS devices. It shows realtime bar numbers of music played back by a playback software. It was all working until I tried a direct ethernet connection between Mac and phone - a scenario that would be quite common in the theatre world where machines dont have internet connection and people dont rely on wifi. How can I choose which interface my app sends the data through? Here is my connection function: func openConnection() { let params = NWParameters.udp params.allowLocalEndpointReuse = true params.includePeerToPeer = true let endpoint = NWEndpoint.hostPort(host: host, port: port) let conn = NWConnection(to: endpoint, using: params) self.connection = conn conn.stateUpdateHandler = { state in switch state { case .ready: print("Multicast connection ready to \(self.host)") UDPClient.console.log("Multicast connection ready to \(self.host)") case .failed(let error): print("Multicast connection failed: \(error)") default: break } } let udpQueue = DispatchQueue(label: "UDPClientQueue") conn.start(queue: udpQueue) } Thanks for any help in advance!
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Jun ’25
How to use Network.framework
It doesn’t seem like there’s any high level, first-party documentation on how to use what is the recommended API for executing networking logic that you otherwise wouldn’t use URLSession for; which is a lot of things. There’s a sample app, and docs on how to choose the right network API in general, but apparently no high level API docs for Network.framework itself. Am I missing something? How do people learn to use this? Know which classes to use? Know the various ways it can be configured?
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216
Mar ’25
Why is localEndpoint not available for NEAppProxyTCPFlow?
NEAppProxyUDPFlow contains below property: open var localEndpoint: NWEndpoint? { get } Why is localEndpoint not available for NEAppProxyTCPFlow? Is there a way to determine the source port of a flow of type NEAppProxyTCPFlow within the following method of NETransparentProxyProvider? override func handleNewFlow(_ flow: NEAppProxyFlow) -> Bool {
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212
Jan ’26