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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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Wi-Fi Aware Sample doesn't build in Xcode 26.0 beta
Hello, I'm trying to build the sample app from Building peer-to-peer apps that demonstrates Wi-Fi Aware. Upon downloading the example source code, opening it in Xcode 26.0 beta, and building the app, the compiler fails with: DeviceDiscoveryPairingView.swift:8:8 No such module 'DeviceDiscoveryUI' Is this a known issue? I know that DeviceDiscoveryUI was previously only a tvOS capability. Thanks
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135
Jun ’25
macOS 26 (Tahoe) lacks Wi‑Fi Aware support — any roadmap or plans?
Hello all, WWDC 2025 introduced Wi‑Fi Aware (NAN) support on iOS 26 for peer-to-peer discovery and direct connections, but I noticed macOS Tahoe doesn’t include it. I couldn’t find any references to Wi‑Fi Aware APIs or framework support in the macOS SDK. Is Apple planning to bring Wi‑Fi Aware to macOS? If so, will this come in a future update to macOS 26 (e.g., 26.x), or is it deferred to macOS 27 or beyond? Thanks for any insights!
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279
Aug ’25
URLCache behavior for request with different header values
Greetings, I would like to understand this URLCache behavior for two different requests to the same end point but with a different header value. Here is a code with comment explaining the behavior. // Create a request to for a url. let url = URL(string: "https://<my url>?f=json")! var request = URLRequest(url: url) // Set custom header with a value. request.setValue("myvalue", forHTTPHeaderField: "CustomField") // Send request to get the response. let (data, response) = try await URLSession.shared.data(for: request) print("data: \(String(describing: String(data: data, encoding: .utf8)))") print("response: \(response)") // Create second request to the same url but with different value of custom header field. var request2 = URLRequest(url: url) request2.setValue("newvalue", forHTTPHeaderField: "CustomField") // Check the URL cache for second request and it returns the response // of the first request even though the second request has different header value. let cachedResponse = URLCache.shared.cachedResponse(for: request2) print("cachedResponse: \(cachedResponse?.response)") Is this a bug in URLCache that request headers are not matched while returning the response? Is this an expected behavior? If yes, why?
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1.6k
Aug ’25
Local network access disabled after macOS restart
My application needs local network access. When it is started for the first time, the user gets a prompt to enable local network access (as expected). The application is then shown as enabled in Privacy & Security / Local Network and local network access is working. If macOS is then shutdown and restarted, local network access is blocked for the application even though it is still shown as enabled in Privacy & Security / Local Network. Local network access can be restored either by toggling permission off and on in Privacy & Security / Local Network or by disabling and enabling Wi-Fi. This behaviour is consistent on Sequoia 15.1. It happens sometimes on 15.0 and 15.0.1 but not every time. Is my application doing something wrong or is this a Sequoia issue? If it is a Sequoia issue, is there some change I can make to my application to work around it?
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3.1k
Jul ’25
Enabling content filter on macOS through MDM
Hi, I'm adding a Content Filtering (FilterDataProvider) on macOS to an existing app and using MDM to avoid user interaction. I start by pushing the following payloads to my machine: com.apple.system-extension-policy com.apple.webcontent-filter And then installing notarized pkg containing my app and the NE. Inspecting the system logs shows the following error: neagent Failed to find a com.apple.networkextension.filter-data extension inside of app com.company_name.app_name.daemon And calling submit(request: .activationRequest(forExtensionWithIdentifier: bundleId, queue: queue)) results in: Missing entitlement com.apple.developer.system-extension.install Installing from Xcode on a SIP disabled machine works fine and both NE and CF are working as expected. I followed the steps mentioned here https://developer.apple.com/forums/thread/737894 however the embedded entitlements already contained -systemextension suffix so I'm not sure if re signing and the subsequent steps are needed. I also double checked that com.apple.developer.system-extension.install is present, certificates are not expired and that get-task-allow is not present in the embedded profile. Here is what my release entitlement file looks like: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>com.apple.developer.networking.networkextension</key> <array> <string>content-filter-provider-systemextension</string> </array> <key>com.apple.security.application-groups</key> <array> <string>com.company_name.app_name.network-extension.content-filter</string> </array> </dict> and my release app entitlement: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>com.apple.developer.endpoint-security.client</key> <true/> <key>com.apple.developer.networking.networkextension</key> <array> <string>content-filter-provider-systemextension</string> </array> <key>com.apple.developer.system-extension.install</key> <true/> </dict> </plist> redacted logs @eskimo may I ask for your help here!
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1k
Jan ’25
How to avoid my local server flows in Transparent App Proxy
I have written the Transparent App Proxy and can capture the network flow and send it to my local server. I want to avoid any processing on the traffic outgoing from my server and establish a connection with a remote server, but instead of connecting to the remote server, it again gets captured and sent back to my local server. I am not getting any clue on how to ignore these flows originating from my server. Any pointers, API, or mechanisms that will help me?
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257
Apr ’25
First update to NWBrowser is always ready, irrespective of Local Networking privacy status
I'm trying to detect the state of Local Network privacy on macOS Sequoia via NWBrowser, as recommended in https://developer.apple.com/documentation/technotes/tn3179-understanding-local-network-privacy Regardless of the state of Local Network privacy - undetermined, allowed or denied, NWBrowser receives an update indicating that its in the ready state. Scanning does not seem to trigger the Local Network privacy alert for me - I have to use the other recommended method to trigger the prompt. Enabling or disabling Local Network privacy does not seem to send any updates for NWBrowser. https://developer.apple.com/forums/thread/666431 seems related, and implies that they did receive further updates to NWBrowser. Filed as FB16077972
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817
Jan ’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.
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445
Mar ’25
Issue with Multicast Response via NWConnectionGroup Behind a Firewall
Hello Everyone, I’m working on a project that involves multicast communication between processes running on different devices within the same network. For all my Apple devices (macOS, iOS, etc.), I am using NWConnectionGroup, which listens on a multicast address "XX.XX.XX.XX" and a specific multicast port. The issue occurs when a requestor (such as a non-Apple process) sends a multicast request, and the server, which is a process running on an Apple device using NWConnectionGroup (the responder), attempts to reply. The problem is that the response is sent from a different ephemeral port rather than the port on which the multicast request was received. If the client is behind a firewall that blocks unsolicited traffic, the firewall only allows incoming packets on the same multicast port used for the initial request. Since the multicast response is sent from a different ephemeral port, the firewall blocks this response, preventing the requestor from receiving it. Questions: Is there a recommended approach within the NWConnectionGroup or Network.framework to ensure that responses to multicast requests are sent from the same port used for the request? Are there any best practices for handling multicast responses in scenarios where the requestor is behind a restrictive firewall? Any insights or suggestions on how to account for this behavior and ensure reliable multicast communication in such environments would be greatly appreciated. Thanks, Harshal
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640
May ’25
No internet connection on wireguard per-app vpn in ios
I am integrating per-app VPN functionality into an iOS app using Wireguard. Chrome is designated as a per-app application for this purpose. However, upon opening Chrome, the VPN icon appears in the notification bar, but there is no internet connection within the Chrome browser. I have verified this behavior with OpenVPN, and it works correctly. While I am familiar with the MDM payload and how to implement per-app VPN, my primary concern is understanding why per-app VPN functionality is not functioning as expected with WireGuard. An observation we made in the server-side logs is the message: "wireguard: wg0: Packet has incorrect size from peer 1"
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1.1k
Feb ’25
Characteristics of a service are lost after successful discovery
My code makes an iPhone use the CBCentralManager to talk to devices peripherals over core bluetooth. After attempting a connect to a peripheral device, I get a didConnect callback on CBCentralManagerDelegate. After this I initiate discovery of services using: peripheral.discoverServices([CBUUID(nsuuid: serviceUUID)]) Since I am only interested in discovering my service of interest and not the others to speed up time to the actual sending of data. This also gives me the didDiscoverServices callback without error prints in which I do the following: guard let services = peripheral.services, !services.isEmpty else { print("Empty services") centralManager.cancelPeripheralConnection(peripheral) return } And for next steps if let serviceOfInterest = services.first(where: {$0.uuid == CBUUID(nsuuid: serviceUUID)}) { //double check for service we want initiateDiscoverCharacteristics(peripheral: peripheral, service: serviceOfInterest) } Below is what initiateDiscoverCharacteristics() does. I basically only tries to discover certain characteristics of the selected service: peripheral.discoverCharacteristics( [CBUUID(nsuuid: readUUID), CBUUID(nsuuid: writeUUID)], for: serviceOfInterest) For this also we get the didDiscoverCharacteristicsFor callback without error prints. Here in this callback however we were not doing the serviceOfInterest check to see that we are getting the callback for the service we expect, since our understanding was that we will get didDiscoverCharacteristicsFor callback for the characteristics on the serviceOfInterest because that is what peripheral.discoverCharacteristics() was initiated for. When we go ahead to write some data/subscribe for notify/read data we have 2 guard statements for services and characteristics of a particular service. The first guard below passes: if(peripheral.services == nil) { print("services yet to be discovered \(peripheral.identifier.uuidString)") return } However the second guard below fails: let serviceOfInterest = peripheral.services?.first(where: {$0.uuid == CBUUID(nsuuid: serviceUUID}) if((serviceOfInterest?.characteristics == nil) || (serviceOfInterest?.characteristics == [])) { print("characteristics yet to be discovered \(peripheral.identifier.uuidString)") return } First of all, does the iPhone go ahead and discover other characteristics and services separately even when we explicitly mention the service and the characteristics it should discover? Now if you say yes and that it maybe the reason of our bug because we didn't do a check for serviceOfInterest in didDiscoverCharacteristicsFor callback, then I have another question. Why don't we get a second/third print in didDiscoverCharacteristicsFor callback signifying that more characteristics were discovered? The peripheral device just disconnects after a set timeout (peripheral device used in our testing does this if we are not communicating with it for a certain amount of time). This issue is extremely rare. We have seen it only twice in our customer base. Both the instances were on the same iPhone 15 Pro. Once a few months back and once recently. Currently, this iPhone is having iOS version 18.1.1 running on it.
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269
Feb ’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&lt;Void, Never&gt;? // 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
Packet Tunnel Provider - sleep
I've implemented a VPN app with Packet Tunnel Provider for MacOS and iOS.I have two questions regarding the Extension's sleep/wake functions:1. If the VPN configuration is set with disconnectOnSleep = false, and at the extension I'm sending keep-alives every X seconds, What would happen when the device enters sleep mode? Will it keep sending keep-alive (because the VPN is configured with disconnectOnSleep=false) ?2. If the VPN configuration is set with disconnectOnSleep = true, and also isOnDemandEnabled = true. When the device enters sleep mode, do I need to disconnect the VPN myself? Or the OS would take care of it? And if I should disconnect it myself, the on-demand won't try to turn it on again (because the on-demand) ?
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5.4k
Feb ’25
URL filter app with multiple configurations
Hello, We've been working on an app that uses the new NEUrlFilter API and we've got a question. Currently, the system is designed with the assumption that a single app == usecase == single remote database. But what if we would like to give the user the ability to use different blocklists? For example, the user may want to: Block scam domains Block tracking domains Block adult domains Or any composition of these 3 What should we do to give the user this option? It seems that we could differentiate different databases by using different PIR service hostnames, but that would also mean that we'll have to send several requests for the same usecase but with different PIR service hostnames (and they'll all share the same app bundle ID). Will these requests be accepted then? If not, is there an alternative? PS: By sending a request I mean submitting this form
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121
Oct ’25
How can implement iOS esim in-app activation
Esim activation. Assuming I already have card data, I use the universal link https://esimsetup.apple.com/esim_qrcode_provisioning?carddata= to install it. However, it always ends up in the system Settings app. The flow: 1. Click the link -&gt; 2. Redirect to Settings -&gt; 3. Show activation dialog. Is there anyway to make the activation flow stay within the app? I couldn't find any documentation for that. This is an example from Revolut app, where the whole flow above happens without leaving the app.
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402
Feb ’25
Get grpc trailer fields through NSURLSession
I'm trying to implement support for grpc http/2 streams using NSURLSession. Almost everything works fine, data streaming is flowing from the server and from the client and responses are coming through my NSURLSessionTaskDelegate. I'm getting the responses and streamed data through the appropriate handlers (didReceiveData, didReceiveResponse). However, I cannot seem to find an API to access the trailers expected by grpc. Specifically, the expected trailer "grpc-status: 0" is in the response, but after the data. Is there no way to gain access to trailers in the NSURLSession Framework?
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161
Oct ’25
Safari block the access to some port of an IP on the whole system
Hi, Since iOS 26 (and any other apple system with a 26 version) there is a very weird behavior in the whole apple ecosystem (iOS, iPadOS, macOS and visionOS). I'm self-hosting a web project called mempool (https://github.com/Retropex/mempool). This project is entirely self-hosted on my own infrastructure, so I have advanced control to be sure it's just not an anti-DDoS feature that makes the bug happen. So the bug is once I visit my website, for example this page (https://mempool.guide/tx/d86192252a6631831e55f814aea901e65407b6dbda77e1abdea8ec27861e9682) the OS will lose the ability to connect to the underlying IP of the domain (mempool.guide) but the issue seems to affect only the HTTPS/HTTP port (443/80). The issue is system wide, not only is Safari. For exemple I have another domain that resolve to the same IP (haf.ovh) and if this link above trigger the bug then I will also lose the ability to connect to https://haf.ovh A temporary fix that I have is that if I turn off wifi/cellular then I turn it on again I can connect again to my server again until the bug is triggered again. I have done test with tcpdump on my server and the connection isn't making it to my server that's why I think it's an OS issue, especially given the fix above. This issue can be reproduced on any apple device out of the box with a system with >v26. All device (Mac, iPad, iPhone, vision) with version pre-26 are completely unaffected by the bug and can freely explore the website without loosing the connection macOS is less affected by this bug, it can be random with it. With iOS/iPadOS it's systematic. Another thing to note is that the same URL on firefox/chrome for iOS doesn't trigger the bug. Let me know if anyone has an idea on what's going on. Thanks, Léo.
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155
Oct ’25
XPC doesn't work with network extension on app upgrade
Our app has a network extension (as I've mentioned lots 😄). We do an upgrade by downloading the new package, stopping & removing all of our components except for the network extension, and then installing the new package, which then loads a LaunchAgent causing the containing app to run. (The only difference between a new install and upgrade is the old extension is left running, but not having anything to tell it what to do, just logs and continues.) On some (but not all) upgrades... nothing ends up able to communicate via XPC with the Network Extension. My simplest cli program to talk to it gets Could not create proxy: Error Domain=NSCocoaErrorDomain Code=4099 "The connection to service named blah was invalidated: failed at lookup with error 3 - No such process." UserInfo={NSDebugDescription=The connection to service named bla was invalidated: failed at lookup with error 3 - No such process.} Could not communicate with blah Restarting the extension by doing a kill -9 doesn't fix it; neither does restarting the control daemon. The only solution we've come across so far is rebooting. I filed FB11086599 about this, but has anyone thoughts about this?
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4.0k
Apr ’25
Failed to enable the Network Extension
In my application, there is a Network Extension with the bundle ID com.xxx.agent.yyy.zzz.ne. There is a user upgraded their system to macOS Sequoia 15.3, they faced an issue where enabling this Network Extension failed. Even after uninstalling the application and the Network Extension, restarting the system, and reinstalling multiple times, the enabling process still failed. it alert: Failed to enable the Network Extension. When checking the status via "systemextension list", it always shows "activated waiting for user". This shows the normal enabling process log: This shows the log when the enabling fails upon clicking. Strangely enough, there is no activation operation log when it fails. What could be the problem?
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698
Feb ’25