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. Moving to Fewer, Larger Transfers forums post Testing Background Session Code forums post 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 NWEndpoint History and Advice 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). WWDC 2017 Session 701 Your Apps and Evolving Network Security Standards [1] — This is generally interesting, but the section starting at 17:40 is, AFAIK, the best information from Apple about how certificate revocation works on modern systems. 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 forums post Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" [1] This video is no longer available from Apple, but the URL should help you locate other sources of this info.

I would like to test running some Thread Networking code on my MacOS machine: import ThreadNetwork let client = THClient() let bIsPreferredAvailable = await client.isPreferredAvailable() but I get some errors when trying to create an instance of the THClient class: Client: -[THClient connectToXPCService]_block_invoke - CTCS XPC Client is interrupted. Client: -[THClient getConnectionEntitlementValidity]_block_invoke - clientProxyWithErrorHandler Error: Error Domain=NSCocoaErrorDomain Code=4097 "connection to service named com.apple.ThreadNetwork.xpc" UserInfo={NSDebugDescription=connection to service named com.apple.ThreadNetwork.xpc} Client: -[THClient init] - XPC Client Init Failed Invalidating XPC connection. Client: -[THClient getConnectionEntitlementValidity]_block_invoke - clientProxyWithErrorHandler Error: Error Domain=NSCocoaErrorDomain Code=4097 "connection to service named com.apple.ThreadNetwork.xpc" UserInfo={NSDebugDescription=connection to service named com.apple.ThreadNetwork.xpc} How can I get the code to run?

I want to check if the device has a internet connection or not by pinging DNS "8.8.8.8". connection.send(content: content, completion: .contentProcessed {[weak self] error in send function is not returning any error even if the host is unreachable. I am checking if I can receive the data or not but connection.receiveMessage function never returns. This is the complete code which I am following: private let networkMonitor = NWPathMonitor() private var connection: NWConnection @MainActor var isConnectedToInternet = false init(host: NWEndpoint.Host = "8.8.8.8", port: NWEndpoint.Port = 53) { let endpoint = NWEndpoint.hostPort(host: host, port: port) connection = NWConnection(to: endpoint, using: .udp) startMonitoring() } private func startMonitoring() { networkMonitor.pathUpdateHandler = { [weak self] path in guard let self else { return } ping(callback: { isSuccess in print("***** ping status:", isSuccess) Task { @MainActor in self.isConnectedToInternet = isSuccess } }) } let queue = DispatchQueue(label: QueueLabel.networkMonitor) networkMonitor.start(queue: queue) } func ping( host: NWEndpoint.Host = "8.8.8.8", port: NWEndpoint.Port = 53, callback: @escaping ((Bool) -> Void) ) { var didSendState = false connection.stateUpdateHandler = {[weak self] state in guard let self = self else { return } guard !didSendState else { if state != .cancelled { cancel(connection) } return } switch state { case .ready: // State is ready now send data let content = "Ping".data(using: .utf8) let startTime = Date() connection.send(content: content, completion: .contentProcessed {[weak self] error in guard let self = self else { return } if error != nil { callback(false) didSendState = true cancel(connection) } else { print("Ping sent, waiting for response...") connection.receiveMessage { [weak self] content, _, _, receiveError in guard let self = self else { return } if let receiveError { print("Error receiving ping: \(receiveError.localizedDescription)") callback(false) } else if let content = content, String(data: content, encoding: .utf8) == "Ping" { let roundTripTime = Date().timeIntervalSince(startTime) print("Ping received! Round-trip time: \(roundTripTime) seconds") callback(true) } else { print("Invalid response received") callback(true) } didSendState = true cancel(connection) } } }) case .failed( _), .waiting( _), .cancelled: didSendState = true callback(false) case .setup, .preparing: // No callback because the ping has not yet succeeded or failed break @unknown default: didSendState = true callback(false) // We don't know what this unknown default means, so cancel pings to be safe cancel(connection) } } connection.start(queue: .main) } func cancel(_ connection: NWConnection) { connection.cancel() } } Can anyone please help what I am doing wrong.

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

on MacOS I am using raw socket and PF_Route options to monitor the routing table changes but looks like that is not supported in iOS what are the other ways to achieve real time monitoring in iOS ?

At WWDC 2015 Apple announced two major enhancements to the Network Extension framework: Network Extension providers — These are app extensions that let you insert your code at various points within the networking stack, including: Packet tunnels via NEPacketTunnelProvider App proxies via NEAppProxyProvider Content filters via NEFilterDataProvider and NEFilterControlProvider Hotspot Helper (NEHotspotHelper) — This allows you to create an app that assists the user in navigating a hotspot (a Wi-Fi network where the user must interact with the network in order to get access to the wider Internet). Originally, using any of these facilities required authorisation from Apple. Specifically, you had to apply for, and be granted access to, a managed capability. In Nov 2016 this policy changed for Network Extension providers. Any developer can now use the Network Extension provider capability like they would any other capability. There is one exception to this rule: Network Extension app push providers, introduced by iOS 14 in 2020, still requires that Apple authorise the use of a managed capability. To apply for that, follow the link in Local push connectivity. Also, the situation with Hotspot Helpers remains the same: Using a Hotspot Helper, requires that Apple authorise that use via a managed capability. To apply for that, follow the link in Hotspot helper. IMPORTANT Pay attention to this quote from the documentation: NEHotspotHelper is only useful for hotspot integration. There are both technical and business restrictions that prevent it from being used for other tasks, such as accessory integration or Wi-Fi based location. The rest of this document answers some frequently asked questions about the Nov 2016 change. #1 — Has there been any change to the OS itself? No, this change only affects the process by which you get the capabilities you need in order to use existing Network Extension framework facilities. Previously these were managed capabilities, meaning their use was authorised by Apple. Now, except for app push providers and Hotspot Helper, you can enable the necessary capabilities using Xcode’s Signing & Capabilities editor or the Developer website. IMPORTANT Some Network Extension providers have other restrictions on their use. For example, a content filter can only be used on a supervised device. These restrictions are unchanged. See TN3134 Network Extension provider deployment for the details. #2 — How exactly do I enable the Network Extension provider capability? In the Signing & Capabilities editor, add the Network Extensions capability and then check the box that matches the provider you’re creating. In the Certificates, Identifiers & Profiles section of the Developer website, when you add or edit an App ID, you’ll see a new capability listed, Network Extensions. Enable that capability in your App ID and then regenerate the provisioning profiles based on that App ID. A newly generated profile will include the com.apple.developer.networking.networkextension entitlement in its allowlist; this is an array with an entry for each of the supported Network Extension providers. To confirm that this is present, dump the profile as shown below. $ security cms -D -i NETest.mobileprovision … <plist version="1.0"> <dict> … <key>Entitlements</key> <dict> <key>com.apple.developer.networking.networkextension</key> <array> <string>packet-tunnel-provider</string> <string>content-filter-provider</string> <string>app-proxy-provider</string> … and so on … </array> … </dict> … </dict> </plist> #3 — I normally use Xcode’s Signing & Capabilities editor to manage my entitlements. Do I have to use the Developer website for this? No. Xcode 11 and later support this capability in the Signing & Capabilities tab of the target editor (r. 28568128 ). #4 — Can I still use Xcode’s “Automatically manage signing” option? Yes. Once you modify your App ID to add the Network Extension provider capability, Xcode’s automatic code signing support will include the entitlement in the allowlist of any profiles that it generates based on that App ID. #5 — What should I do if I previously applied for the Network Extension provider managed capability and I’m still waiting for a reply? Consider your current application cancelled, and use the new process described above. #6 — What should I do if I previously applied for the Hotspot Helper managed capability and I’m still waiting for a reply? Apple will continue to process Hotspot Helper managed capability requests and respond to you in due course. #7 — What if I previously applied for both Network Extension provider and Hotspot Helper managed capabilities? Apple will ignore your request for the Network Extension provider managed capability and process it as if you’d only asked for the Hotspot Helper managed capability. #8 — On the Mac, can Developer ID apps host Network Extension providers? Yes, but there are some caveats: This only works on macOS 10.15 or later. Your Network Extension provider must be packaged as a system extension, not an app extension. You must use the *-systemextension values for the Network Extension entitlement (com.apple.developer.networking.networkextension). For more on this, see Exporting a Developer ID Network Extension. #9 — After moving to the new process, my app no longer has access to the com.apple.managed.vpn.shared keychain access group. How can I regain that access? Access to this keychain access group requires another managed capability. If you need that, please open a DTS code-level support request and we’ll take things from there. IMPORTANT This capability is only necessary if your VPN supports configuration via a configuration profile and needs to access credentials from that profile (as discussed in the Profile Configuration section of the NETunnelProviderManager Reference). Many VPN apps don’t need this facility. If you were previously granted the Network Extension managed capability (via the process in place before Nov 2016), make sure you mention that; restoring your access to the com.apple.managed.vpn.shared keychain access group should be straightforward in that case. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" Revision History 2025-11-11 Removed the discussion of TSI assets because those are no longer a thing. 2025-09-12 Adopted the code-level support request terminology. Made other minor editorial changes. 2023-01-11 Added a discussion of Network Extension app push providers. Added a link to Exporting a Developer ID Network Extension. Added a link to TN3134. Made significant editorial changes. 2020-02-27 Fixed the formatting. Updated FAQ#3. Made minor editorial changes. 2020-02-16 Updated FAQ#8 to account for recent changes. Updated FAQ#3 to account for recent Xcode changes. Made other editorial changes. 2016-01-25 Added FAQ#9. 2016-01-6 Added FAQ#8. 2016-11-11 Added FAQ#5, FAQ#6 and FAQ#7. 2016-11-11 First posted.

Problem description Since macOS Sequoia, our users have experienced issues with multicast traffic in our macOS app. Regularly, the app starts but cannot receive multicast, or multicast eventually stops mid-execution. The app sometimes asks again for Local Network permission, while it was already allowed so. Several versions of our app on a single machine are sometimes (but not always) shown as different instances in the System Settings > Privacy & Security > Local Network list. And when several instances are shown in that list, disabling one disables all of them, but it does not actually forbids the app from receiving multicast traffic. All of those issues are experienced by an increasing number of users after they update their system from macOS 14 to macOS 15 or 26, and many of them have reported networking issues during production-critical moments. We haven't been able to find the root cause of those issues, so we built a simple test app, called "FM Mac App Test", that can reproduce multicast issues. This app creates a GCDAsyncUdpSocket socket to receive multicast packets from a piece of hardware we also develop, and displays a simple UI showing if such packets are received. The app is entitled with "Custom Network Protocol", is built against x86_64 and arm64, and is archived (signed and notarized). We can share the source code if requested. Out of the many issues our main app exhibits, the test app showcases some: The app asks several times for Local Network permission, even after being allowed so previously. After allowing the app's Local Network and rebooting the machine, the System Settings > Privacy & Security > Local Network does not show the app, and the app asks again for Local Network access. The app shows a different Local Network Usage Description than in the project's plist. Several versions of the app appear as different instances in the Privacy list, and behave strangely. Toggling on or off one instance toggles the others. Only one version of the app seems affected by the setting, the other versions always seem to have access to Local Network even when the toggle is set to off. We even did see messages from different app versions in different user accounts. This seems to contradicts Apple's documentation that states user accounts have independent Privacy settings. Can you help us understand what we are missing (in terms of build settings, entitlements, proper archiving...) so our app conforms to what macOS expects for proper Local Network behavior? Related material Local Network Privacy breaks Application: this issue seemed related to ours, but the fix was to ensure different versions of the app have different UUIDs. We ensured that ourselves, to no improvement. Local Network FAQ Technote TN3179 Steps to Reproduce Test App is developed on Xcode 15.4 (15F31d) on macOS 14.5 (23F79), and runs on macOS 26.0.1 (25A362). We can share the source code if requested. On a clean install of macOS Tahoe (our test setup used macOS 26.0.1 on a Mac mini M2 8GB), we upload the app (version 5.1). We run the app, make sure the selected NIC is the proper one, and open the multicast socket. The app asks us to allow Local Network, we allow it. The alert shows a different Local Network Usage Description than the one we set in our project's plist. The app properly shows packets are received from the console on our LAN. We check the list in System Settings > Privacy & Security > Local Network, it includes our app properly allowed. We then reboot the machine. After reboot, the same list does not show the app anymore. We run the app, it asks again about Local Network access (still with incorrect Usage Description). We allow it again, but no console packet is received yet. Only after closing and reopening the socket are the console packets received. After a 2nd reboot, the System Settings > Privacy & Security > Local Network list shows correctly the app. The app seems to now run fine. We then upload an updated version of the same app (5.2), also built and notarized. The 2nd version is simulating when we send different versions of our main app to our users. The updated version has a different UUID than the 1st version. The updated version also asks for Local Network access, this time with proper Usage Description. A 3rd updated version of the app (5.3, also with unique UUID) behaves the same. The System Settings > Privacy & Security > Local Network list shows three instances of the app. We toggle off one of the app, all of them toggle off. The 1st version of the app (5.1) does not have local network access anymore, but both 2nd and 3rd versions do, while their toggle button seems off. We toggle on one of the app, all of them toggle on. All 3 versions have local network access.

We updated the apple-app-site-association file two weeks ago and we are only seeing the new content from Apple's CDN serving certain regions such as Texas and Canada. Regions such as Colorado intermittently sees the old content and California has been receiving the old content all the time. Is this a known issue? If yes, when can we expect this to be fixed and where to check the status? If not, can someone in charge of CDN please look into this? Let me know if there is a better place to report this issue and get the support ASAP though. Thank you in advance and happy new year!

When running my app with Xcode16.4, it crashed with the error: dyld[1045]: Symbol not found: ___res_9_state Referenced from: <8B329554-5BEF-38D0-BFCD-1731FA6120CB> /private/var/containers/Bundle/Application/00C941BA-E397-4D0B-B280-E75583FF2890/xxx.app/xxx.debug.dylib Expected in: <7D74C679-8F55-3A01-9AA2-C205A4A19D3E> /usr/lib/libresolv.9.dylib The ___res_9_state related code in my app is: let state = __res_9_state() res_9_ninit(state) var servers = [res_9_sockaddr_union](repeating: res_9_sockaddr_union(), count: Int(MAXNS)) let found = Int(res_9_getservers(state, &servers, Int32(MAXNS))) res_9_nclose(state) if found > 0 { return Array(servers[0..<found]).filter() { $0.sin.sin_len > 0 } } else { return [] } Previously, __res_9_state() could run normally in Xcode 16.1 How to fix this problem?

Hi, I have a problem with my OpenVPN connection on my app with iOS 14.4. I perform my VPN configuration from an oven file, with a NETunnelProviderManager protocol, but when I perform the startVPNTunnel, it starts connecting and immediately disconnects. The error I see in the logs is the following: NESMVPNSession[Primary Tunnel:OpenVPN Client: -----(null)]: status changed to disconnected, last stop reason Plugin was disabled This happens to me when running my app on a physical iPad. Regards import NetworkExtension import OpenVPNAdapter class VPNConnection {          var connectionStatus = "Disconnected"              var myProviderManager: NETunnelProviderManager?          func manageConnectionChanges( manager:NETunnelProviderManager ) - String {         NSLog("Waiting for changes");         var status = "Disconnected"                  NotificationCenter.default.addObserver(forName: NSNotification.Name.NEVPNStatusDidChange, object: manager.connection, queue: OperationQueue.main, using: { notification in                          let baseText = "VPN Status is "                          switch manager.connection.status {             case .connected:                 status = "Connected"             case .connecting:                 status = "Connecting"             case .disconnected:                 status = "Disconnected"             case .disconnecting:                 status = "Disconnecting"             case .invalid:                 status = "Invalid"             case .reasserting:                 status = "Reasserting"             default:                 status = "Connected"             }                          self.connectionStatus = status                          NSLog(baseText+status)                      });         return status     }          func createProtocolConfiguration() - NETunnelProviderProtocol {         guard             let configurationFileURL = Bundle.main.url(forResource: "app-vpn", withExtension: "ovpn"),             let configurationFileContent = try? Data(contentsOf: configurationFileURL)         else {             fatalError()         }                  let tunnelProtocol = NETunnelProviderProtocol()         tunnelProtocol.serverAddress = ""         tunnelProtocol.providerBundleIdentifier = "com.app.ios"                  tunnelProtocol.providerConfiguration = ["ovpn": String(data: configurationFileContent, encoding: .utf8)! as Any]         tunnelProtocol.disconnectOnSleep = false                  return tunnelProtocol     }          func startConnection(completion:@escaping () - Void){         self.myProviderManager?.loadFromPreferences(completionHandler: { (error) in             guard error == nil else {                 // Handle an occurred error                 return             }                          do {                 try self.myProviderManager?.connection.startVPNTunnel()                 print("Tunnel started")             } catch {                 fatalError()             }         })     }          func loadProviderManager(completion:@escaping () - Void) {                           NETunnelProviderManager.loadAllFromPreferences { (managers, error) in             guard error == nil else {                 fatalError()                 return             }                          self.myProviderManager = managers?.first ?? NETunnelProviderManager()             self.manageConnectionChanges(manager: self.myProviderManager!)                          self.myProviderManager?.loadFromPreferences(completionHandler: { (error) in                 guard error == nil else {                     fatalError()                     return                 }                                  let tunnelProtocol = self.createProtocolConfiguration()                                  self.myProviderManager?.protocolConfiguration = tunnelProtocol                 self.myProviderManager?.localizedDescription = "OpenVPN Client Ubic"                                  self.myProviderManager?.isEnabled = true                                  self.myProviderManager?.isOnDemandEnabled = false                                  self.myProviderManager?.saveToPreferences(completionHandler: { (error) in                     if error != nil  {                         // Handle an occurred error                         fatalError()                     }                     self.startConnection {                         print("VPN loaded")                     }                 })             })         }     } }

Apple multi-peer with 12 devices is unstable. Dear All, Has anyone tried Apple multi-peer with 12 devices connected? We are building an application relying on multi-peer where 12 Ipads will be updating data and each device needs to share data between. Can anyone tell me if we can use multi-peer framework for connecting 12 devices in the multi-peer network? We are facing stability problems in the connection when we connect 12 devices in the network.

Hi Team, I have a Network Extension application and UI frontend for it. The UI frontend talks to the Network Extension using XPC, as provided by NEMachServiceName. On M2 machine, The application and XPC connection works fine on clean installation. But, when the application is upgraded, the XPC connection keeps failing. Upgrade steps: PreInstall script kills the running processes, both UI and Network Extension Let installation continue PostInstall script to launch the application after installation complete. Following code is successful to the point of resume from UI application NSXPCInterface *exportedInterface = [NSXPCInterface interfaceWithProtocol:@protocol(IPCUIObject)]; newConnection.exportedInterface = exportedInterface; newConnection.exportedObject = delegate; NSXPCInterface *remoteObjectInterface = [NSXPCInterface interfaceWithProtocol:@protocol(IPCExtObject)]; newConnection.remoteObjectInterface = remoteObjectInterface; self.currentConnection = newConnection; [newConnection resume]; But it fails to get the object id<IPCExtObject> providerProxy = [self.currentConnection remoteObjectProxyWithErrorHandler:^(NSError *registerError) { }]; Please note, this only fails for M2. For M1, this exact code is running fine. Additionally, if I uninstall the application by dropping it in Trash and then installing the newer version, then too, the application works fine.

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

Transport Layer Security (TLS) is the most important security protocol on the Internet today. Most notably, TLS puts the S into HTTPS, adding security to the otherwise insecure HTTP protocol. IMPORTANT TLS is the successor to the Secure Sockets Layer (SSL) protocol. SSL is no longer considered secure and it’s now rarely used in practice, although many folks still say SSL when they mean TLS. TLS is a complex protocol. Much of that complexity is hidden from app developers but there are places where it’s important to understand specific details of the protocol in order to meet your requirements. This post explains the fundamentals of TLS, concentrating on the issues that most often confuse app developers. Note The focus of this is TLS-PKI, where PKI stands for public key infrastructure. This is the standard TLS as deployed on the wider Internet. There’s another flavour of TLS, TLS-PSK, where PSK stands for pre-shared key. This has a variety of uses, but an Apple platforms we most commonly see it with local traffic, for example, to talk to a Wi-Fi based accessory. For more on how to use TLS, both TLS-PKI and TLS-PSK, in a local context, see TLS For Accessory Developers. Server Certificates For standard TLS to work the server must have a digital identity, that is, the combination of a certificate and the private key matching the public key embedded in that certificate. TLS Crypto Magic™ ensures that: The client gets a copy of the server’s certificate. The client knows that the server holds the private key matching the public key in that certificate. In a typical TLS handshake the server passes the client a list of certificates, where item 0 is the server’s certificate (the leaf certificate), item N is (optionally) the certificate of the certificate authority that ultimately issued that certificate (the root certificate), and items 1 through N-1 are any intermediate certificates required to build a cryptographic chain of trust from 0 to N. Note The cryptographic chain of trust is established by means of digital signatures. Certificate X in the chain is issued by certificate X+1. The owner of certificate X+1 uses their private key to digitally sign certificate X. The client verifies this signature using the public key embedded in certificate X+1. Eventually this chain terminates in a trusted anchor, that is, a certificate that the client trusts by default. Typically this anchor is a self-signed root certificate from a certificate authority. Note Item N is optional for reasons I’ll explain below. Also, the list of intermediate certificates may be empty (in the case where the root certificate directly issued the leaf certificate) but that’s uncommon for servers in the real world. Once the client gets the server’s certificate, it evaluates trust on that certificate to confirm that it’s talking to the right server. There are three levels of trust evaluation here: Basic X.509 trust evaluation checks that there’s a cryptographic chain of trust from the leaf through the intermediates to a trusted root certificate. The client has a set of trusted root certificates built in (these are from well-known certificate authorities, or CAs), and a site admin can add more via a configuration profile. This step also checks that none of the certificates have expired, and various other more technical criteria (like the Basic Constraints extension). Note This explains why the server does not have to include the root certificate in the list of certificates it passes to the client; the client has to have the root certificate installed if trust evaluation is to succeed. In addition, TLS trust evaluation (per RFC 2818) checks that the DNS name that you connected to matches the DNS name in the certificate. Specifically, the DNS name must be listed in the Subject Alternative Name extension. Note The Subject Alternative Name extension can also contain IP addresses, although that’s a much less well-trodden path. Also, historically it was common to accept DNS names in the Common Name element of the Subject but that is no longer the case on Apple platforms. App Transport Security (ATS) adds its own security checks. Basic X.509 and TLS trust evaluation are done for all TLS connections. ATS is only done on TLS connections made by URLSession and things layered on top URLSession (like WKWebView). In many situations you can override trust evaluation; for details, see Technote 2232 HTTPS Server Trust Evaluation). Such overrides can either tighten or loosen security. For example: You might tighten security by checking that the server certificate was issued by a specific CA. That way, if someone manages to convince a poorly-managed CA to issue them a certificate for your server, you can detect that and fail. You might loosen security by adding your own CA’s root certificate as a trusted anchor. IMPORTANT If you rely on loosened security you have to disable ATS. If you leave ATS enabled, it requires that the default server trust evaluation succeeds regardless of any customisations you do. Mutual TLS The previous section discusses server trust evaluation, which is required for all standard TLS connections. That process describes how the client decides whether to trust the server. Mutual TLS (mTLS) is the opposite of that, that is, it’s the process by which the server decides whether to trust the client. Note mTLS is commonly called client certificate authentication. I avoid that term because of the ongoing industry-wide confusion between certificates and digital identities. While it’s true that, in mTLS, the server authenticates the client certificate, to set this up on the client you need a digital identity, not a certificate. mTLS authentication is optional. The server must request a certificate from the client and the client may choose to supply one or not (although if the server requests a certificate and the client doesn’t supply one it’s likely that the server will then fail the connection). At the TLS protocol level this works much like it does with the server certificate. For the client to provide this certificate it must apply a digital identity, known as the client identity, to the connection. TLS Crypto Magic™ assures the server that, if it gets a certificate from the client, the client holds the private key associated with that certificate. Where things diverge is in trust evaluation. Trust evaluation of the client certificate is done on the server, and the server uses its own rules to decided whether to trust a specific client certificate. For example: Some servers do basic X.509 trust evaluation and then check that the chain of trust leads to one specific root certificate; that is, a client is trusted if it holds a digital identity whose certificate was issued by a specific CA. Some servers just check the certificate against a list of known trusted client certificates. When the client sends its certificate to the server it actually sends a list of certificates, much as I’ve described above for the server’s certificates. In many cases the client only needs to send item 0, that is, its leaf certificate. That’s because: The server already has the intermediate certificates required to build a chain of trust from that leaf to its root. There’s no point sending the root, as I discussed above in the context of server trust evaluation. However, there are no hard and fast rules here; the server does its client trust evaluation using its own internal logic, and it’s possible that this logic might require the client to present intermediates, or indeed present the root certificate even though it’s typically redundant. If you have problems with this, you’ll have to ask the folks running the server to explain its requirements. Note If you need to send additional certificates to the server, pass them to the certificates parameter of the method you use to create your URLCredential (typically init(identity:certificates:persistence:)). One thing that bears repeating is that trust evaluation of the client certificate is done on the server, not the client. The client doesn’t care whether the client certificate is trusted or not. Rather, it simply passes that certificate the server and it’s up to the server to make that decision. When a server requests a certificate from the client, it may supply a list of acceptable certificate authorities [1]. Safari uses this to filter the list of client identities it presents to the user. If you are building an HTTPS server and find that Safari doesn’t show the expected client identity, make sure you have this configured correctly. If you’re building an iOS app and want to implement a filter like Safari’s, get this list using: The distinguishedNames property, if you’re using URLSession The sec_protocol_metadata_access_distinguished_names routine, if you’re using Network framework [1] See the certificate_authorities field in Section 7.4.4 of RFC 5246, and equivalent features in other TLS versions. Self-Signed Certificates Self-signed certificates are an ongoing source of problems with TLS. There’s only one unequivocally correct place to use a self-signed certificate: the trusted anchor provided by a certificate authority. One place where a self-signed certificate might make sense is in a local environment, that is, securing a connection between peers without any centralised infrastructure. However, depending on the specific circumstances there may be a better option. TLS For Accessory Developers discusses this topic in detail. Finally, it’s common for folks to use self-signed certificates for testing. I’m not a fan of that approach. Rather, I recommend the approach described in QA1948 HTTPS and Test Servers. For advice on how to set that up using just your Mac, see TN2326 Creating Certificates for TLS Testing. TLS Standards RFC 6101 The Secure Sockets Layer (SSL) Protocol Version 3.0 (historic) RFC 2246 The TLS Protocol Version 1.0 RFC 4346 The Transport Layer Security (TLS) Protocol Version 1.1 RFC 5246 The Transport Layer Security (TLS) Protocol Version 1.2 RFC 8446 The Transport Layer Security (TLS) Protocol Version 1.3 RFC 4347 Datagram Transport Layer Security RFC 6347 Datagram Transport Layer Security Version 1.2 RFC 9147 The Datagram Transport Layer Security (DTLS) Protocol Version 1.3 Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" Revision History: 2025-11-21 Clearly defined the terms TLS-PKI and TLS-PSK. 2024-03-19 Adopted the term mutual TLS in preference to client certificate authentication throughout, because the latter feeds into the ongoing certificate versus digital identity confusion. Defined the term client identity. Added the Self-Signed Certificates section. Made other minor editorial changes. 2023-02-28 Added an explanation mTLS acceptable certificate authorities. 2022-12-02 Added links to the DTLS RFCs. 2022-08-24 Added links to the TLS RFCs. Made other minor editorial changes. 2022-06-03 Added a link to TLS For Accessory Developers. 2021-02-26 Fixed the formatting. Clarified that ATS only applies to URLSession. Minor editorial changes. 2020-04-17 Updated the discussion of Subject Alternative Name to account for changes in the 2019 OS releases. Minor editorial updates. 2018-10-29 Minor editorial updates. 2016-11-11 First posted.

I have an issue that causes multiple instances of the push provider to be initialized. And I'd like to ask you what could trigger the instantiation NEAppPushProvider subclass. It seems like it's being triggered excessively. If there's documentation that I have overlooked then just show it to me and I'll be on my way. Here's the details. But really all I want to know is why is my subclass for NEAppPushProvider keeps getting initialized. If you can answer me that than maybe all these details don't really matter but here they are. Here's why I believe there's multiple push provider. I see logs for my push provider initializing but I don't see it de-initializing. I also see redundant logs showing multiple instances trying to log into my server. Each time it initializes, an additional log is added for trying to log into my server. In the app, the system saves it's configuration shortly after initialization, after saving and loading the push configuration, the app doesn't touch config. Meanwhile in the extension, after 8 or so hours, the extension starts creating a new instance of the push provider. Then a few hours later it does it again. And again. Until the watch dog kills us for wasting too much CPU. Normally on a fresh install, I'll observe turning off the wifi to call stop on the push provider and later have the push provider de-initialize. The extension maintains a socket connection to the server, the server can send it messages to display push notifications. The software runs on hospital networks, which will not have access to the internet. It seems like the connection to the server is stable from the logs. I don't detect any disconnections. I'll check with the server to confirm. In the app I call removeFromPreferences to clear out any extensions before logging in/saving push configurations. And I call saveToPreferences on the NEAppPushManager. I do this to make sure I don't have more than one push configuration saved at one time. I also have many logs looking out for this. I used the sample code from apple as the basis of the my own Push Manager. I can post code if you deem it necessary. Hope to here from you soon. Thank you.

Hello, I’m reviewing the open-source mDNSResponder repository and have a question regarding licensing/provenance in mDNSCore/DNSDigest.c file. That file contains an embedded notice stating that parts of the MD5/digest implementation were derived from older OpenSSL sources and therefore include the legacy OpenSSL/SSLeay license text, even though OpenSSL itself is now Apache-2.0 starting from version 3.0. The legacy OpenSSL/SSLeay license is widely understood to impose additional attribution and notice requirements compared to Apache-2.0, and some downstream projects prefer to avoid it when a permissively licensed alternative is available. Repository: https://github.com/apple-oss-distributions/mDNSResponder File: https://github.com/apple-oss-distributions/mDNSResponder/blob/main/mDNSCore/DNSDigest.c#L66 I’d like to clarify a few points: Is the MD5/digest code in DNSDigest.c still based on pre–OpenSSL-3.0 sources, such that retaining the legacy OpenSSL/SSLeay license block is intentional and required? If the goal were to simplify licensing (Apache-2.0 only), would Apple consider replacing this MD5 implementation with an Apache-2.0–licensed alternative (for example, code derived from OpenSSL 3.x or another permissive implementation)? Are there any technical or policy reasons (compatibility, crypto policy, platform APIs) that make such a replacement undesirable? Since GitHub issues and PRs are restricted for this repository, I’m asking here for guidance. If maintainers agree that such an update would be useful, I’d be happy to help by preparing a PR for review. I've also created a feedback report for this topic, the reference ID is FB21269078. Thanks for any clarification.

Our app receives real-time GPS and aircraft data from devices via UDP broadcast and/or multicast on a WiFi network created by the device. We have identified that the iPhone or iPad will just stop receiving UDP broadcast/multicast data for an interval of time. In general, it appears after roughly every 128KB of data is received. In the attached screenshot from Xcode instruments, you can see the data reception alternating on/off. We have verified with Wireshark that the data is still flowing during that entire time period. And by tracking bytes received the app ultimately receives about 55% of the bytes, which tracks with the Network graph. We have used different approaches to the network code, including GCDAsyncUdpSocket, BSD Sockets, and the Network framework. We've tried it on background threads and the main thread. Tested it on iPads and iPhones. All produce the same result. The data is just never reaching the app code. Any insight on what may be temporarily disabling data reception?

Hi there, can some one help how to debug this crashes? where I can start to find root causes of this crashes. I've got lot of these NSInvalidArgumentException crashes in myapp last version I have no idea how to reproduce these issues since it doesn't point to any specific code on myapp, so I don't know how to start Fatal Exception: NSInvalidArgumentException -[NWConcrete_nw_protocol_options copyWithZone:]: unrecognized selector sent to instance 0x283391d60 Fatal Exception: NSInvalidArgumentException -[NSConcreteHashTable lengthOfBytesUsingEncoding:]: unrecognized selector sent to instance 0x281d4cbe0 Fatal Exception: NSInvalidArgumentException -[_NSXPCConnectionExportedObjectTable lengthOfBytesUsingEncoding:]: unrecognized selector sent to instance 0x2829d11d0 Fatal Exception: NSInvalidArgumentException -[OS_dispatch_group lengthOfBytesUsingEncoding:]: unrecognized selector sent to instance 0x281a11900 Fatal Exception: NSInvalidArgumentException -[__NSCFData getBytes:maxLength:usedLength:encoding:options:range:remainingRange:]: unrecognized selector sent to instance 0x28210e440 Fatal Exception: NSInvalidArgumentException -[_NSCoreTypesetterLayoutCache copyWithZone:]: unrecognized selector sent to instance 0x283bbc730 Thanks com.kitabisa.ios_issue_dd3c71c96cddb5bb99874640746439d6_crash_session_de9bb41c2b7e43fa9ccfc42e0f649aa3_DNE_0_v2_stacktrace.txt

Hi everyone, I’m currently developing a macOS app that is distributed via a DMG file on our website. The app includes an App Extension (appex) for Network Extension functionality. I’m wondering if distributing via DMG on the web requires the app extension to be implemented as a System Extension instead of an App Extension. Is it necessary to migrate to System Extension for web-based DMG distribution, or can I continue using App Extension as is? Any insights or recommendations would be greatly appreciated. Thank you!

Is Apple's Wi-Fi Aware certified by the Wi-Fi Alliance? Is there any non-compliance of Apple's Wi-Fi Aware with the Wi-Fi Alliance standards? Does Apple have a roadmap to switch AWDL to Wi-Fi Aware? Does Apple have plans to adopt Wi-Fi Aware in Mac computers?

I need to know the https address of a certain page within my app. This is going to be used as a redirect URL. I don't think it is a good idea to use deep links because it has to be an https address. I don't think Universal Links will work because it is not my website that I will be communicating with.