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 Wi-Fi (general): How to modernize your captive network developer news post Wi-Fi Fundamentals forums post Filing a Wi-Fi Bug Report forums post Working with a Wi-Fi Accessory forums post — This is part of the Extra-ordinary Networking series. Wi-Fi (iOS): TN3111 iOS Wi-Fi API overview technote Wi-Fi Aware framework documentation WirelessInsights framework documentation iOS Network Signal Strength forums post Network Extension Resources Wi-Fi on macOS: Forums tag: Core WLAN Core WLAN framework documentation 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 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.

1、已经检查过手机的存储空间，还有一百多G的空间。app端进行网络接口情况的时候报错了，报错信息如下： Error : Error Domain=NSPOSIXErrorDomain Code=28 "No space left on device" UserInfo={_NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <7DB1CBFD-B9BE-422D-9C9A-78D8FC04DC1B>.<76>, _kCFStreamErrorDomainKey=1, _kCFStreamErrorCodeKey=28, _NSURLErrorRelatedURLSessionTaskErrorKey=( "LocalDataTask <7DB1CBFD-B9BE-422D-9C9A-78D8FC04DC1B>.<76>" ), _NSURLErrorNWPathKey=satisfied (Path is satisfied), interface: pdp_ip0[lte], ipv4, ipv6, dns, expensive, estimated upload: 65536Bps, uses cell} 2、手机型号是iPhone 15 Plus，iOS 17.6.1

Hi, I'm very new to everything related to networking and I've been trying to make some sort of "parental control" app for macOS where if the user tries to access some website domain (e.g youtube.com) the request is denied and the user can't access the website. Turns out I used NEFilterDataProvider and NEDNSProxyProvider to achieve that but it's not 100% bullet proof. First problem I had is that most of the time I can't access the hostname in the NEFilterDataProvider when trying to extract it from the socketFlow.remoteEndpoint. Most of the time I get the ipv4. And the problem is : I don't know the IPV4 behind the domains, specially when they're changing frequently. if let socketFlow = flow as? NEFilterSocketFlow { let remoteEndpoint = socketFlow.remoteFlowEndpoint switch remoteEndpoint { case .hostPort(let host, _): switch host { case .name(let hostname, _): log.info("🌿 Intercepted hostname: \(hostname, privacy: .public)") case .ipv4(let ipv4): let ipv4String = ipv4.rawValue.map { String($0) }.joined(separator: ".") log.info("🌿 Intercepted IPV4: \(ipv4String, privacy: .public)") So that's why I used the DNSProxyProvider. With it I can get the domains. I succeeded to drop some of the flows by not writing the datagrams when I see a domain to block, but that does not work 100% of the time and sometimes, for youtube.com for example then the website is still reachable (and sometimes it works successfully and I can't access it). I guess because the IP behind the domain has already been resolved and so it's cached somewhere and the browser does not need to send an UDP request anymore to know the IP behind the domain? Is there a 100% bullet proof way to block traffic to specific domains? Ideally I would like to get rid of the DNSProxyProvider and use only the NEFilterDataProvider but if I can't access the hostnames then I don't see how to do it.

Hello, I am in a very similar situation as described in the thread: https://developer.apple.com/forums/thread/655183 Context: I am working on an app that receives data from a hardware device through its Wifi network, and the hardware is not connected to the internet. Now, I would need to call some API while still connected to hardware so I would need to use the cellular data. As mentioned on the thread, I can achieve this via Network framework, using the requiredInterfaceType property. But Is there any other way I can achieve this? I can also do some suggestion on the hardware if that's helpful. Thank you!

Hi! I recently had an idea to build an iOS app that allows users to create a system-level block of specified web domains by curating a "blacklist" on their device. If the user, for instance, inputs "*example.com" to their list, their iPhone would be blocked from relaying that network traffic to their ISP/DNS, and hence return an error message ("iPhone can't open the page because the address is invalid") instead of successfully fetching the response from example.com's servers. The overarching goal of this app would be to allow users to time-block their use of specified websites/apps and grant them greater agency over their technology consumption, and I thought that an app that blocks traffic at the network level, combined with the ability to control when to/not to allow access, would be a powerful alternative to the existing implementations out there that work more on the browser-level (eg. via Safari extension, which is isolated to the scope of user's Safari browser) or via Screen Time (which can be easy to bypass by inputting one's passcode). Another thing to mention is that since the app would serve as a local DNS proxy (instead of relying on a third party DNS resolver), none of their internet activity will be collected/transmitted off-device and be used for commercial purposes. I feel particularly driven to create a privacy-centered app in this way, since no user data needs to be harvested to implement this kind of filtering. I'd also love to get suggestions for a transparent privacy policy that respects users control over their device. With all this said, I found that the Network Extension APIs may be the only way that an app like this could be built on iOS and, I wanted to ask if the above-mentioned use case of Network Extension would be eligible to be granted access to its entitlement before I go ahead and purchase the $99/year Apple Developer Program membership. Happy to provide further information, and I'd also particularly be open to any mentions of existing solutions out there (since I might have missed some in my search). Maybe something like this already exists, in which case it'd be great to know in any case! :). Thank you so much in advance!

For our outdoor power supply company that builds public WiFi networks at camping sites, we want to implement the following features in our app: Scan surrounding WiFi networks When detecting specific public WiFi SSIDs, provide users with corresponding passwords Automatically connect to those WiFi networks Regarding the NEHotspotHelper API permission application, when I clicked on https://developer.apple.com/contact/request/network-extension, it redirected me to https://developer.apple.com/unauthorized/. I'm not sure where to properly apply for this permission now.

I am using a URLSessionWebSocketTask. When trying to receive messages while the app is backgrounded, the receive() method fails with an NSError where the domain is NSPOSIXErrorDomain and the code is ECONNABORTED. That behavior is good. However, when this happens, the URLSessionWebSocketTask reports a closeCode of invalid, which is supposed to denote that the connection is still open. However, the connection state property is reporting completed. I feel that the closeCode property should be reporting something like abnormalClosure in this case. Either way, this seems like a bug or the documentation is incorrect.

I've recently updated one of our CI mac mini's to Sequoia in preparation for the transition to Tahoe later this year. Most things seemed to work just fine, however I see this dialog whenever the UI Tests try to run. This application BoostBrowerUITest-Runner is auto-generated by Xcode to launch your application and then run your UI Tests. We do not have any control over it, which is why this is most surprising. I've checked the codesigning identity with codesign -d -vvvv as well as looked at it's Info.plist and indeed the usage descriptions for everything are present (again, this is autogenerated, so I'm not surprised, but just wanted to confirm the string from the dialog was coming from this app) &lt;?xml version="1.0" encoding="UTF-8"?&gt; &lt;!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"&gt; &lt;plist version="1.0"&gt; &lt;dict&gt; &lt;key&gt;BuildMachineOSBuild&lt;/key&gt; &lt;string&gt;22A380021&lt;/string&gt; &lt;key&gt;CFBundleAllowMixedLocalizations&lt;/key&gt; &lt;true/&gt; &lt;key&gt;CFBundleDevelopmentRegion&lt;/key&gt; &lt;string&gt;en&lt;/string&gt; &lt;key&gt;CFBundleExecutable&lt;/key&gt; &lt;string&gt;BoostBrowserUITests-Runner&lt;/string&gt; &lt;key&gt;CFBundleIdentifier&lt;/key&gt; &lt;string&gt;company.thebrowser.Browser2UITests.xctrunner&lt;/string&gt; &lt;key&gt;CFBundleInfoDictionaryVersion&lt;/key&gt; &lt;string&gt;6.0&lt;/string&gt; &lt;key&gt;CFBundleName&lt;/key&gt; &lt;string&gt;BoostBrowserUITests-Runner&lt;/string&gt; &lt;key&gt;CFBundlePackageType&lt;/key&gt; &lt;string&gt;APPL&lt;/string&gt; &lt;key&gt;CFBundleShortVersionString&lt;/key&gt; &lt;string&gt;1.0&lt;/string&gt; &lt;key&gt;CFBundleSignature&lt;/key&gt; &lt;string&gt;????&lt;/string&gt; &lt;key&gt;CFBundleSupportedPlatforms&lt;/key&gt; &lt;array&gt; &lt;string&gt;MacOSX&lt;/string&gt; &lt;/array&gt; &lt;key&gt;CFBundleVersion&lt;/key&gt; &lt;string&gt;1&lt;/string&gt; &lt;key&gt;DTCompiler&lt;/key&gt; &lt;string&gt;com.apple.compilers.llvm.clang.1_0&lt;/string&gt; &lt;key&gt;DTPlatformBuild&lt;/key&gt; &lt;string&gt;24A324&lt;/string&gt; &lt;key&gt;DTPlatformName&lt;/key&gt; &lt;string&gt;macosx&lt;/string&gt; &lt;key&gt;DTPlatformVersion&lt;/key&gt; &lt;string&gt;15.0&lt;/string&gt; &lt;key&gt;DTSDKBuild&lt;/key&gt; &lt;string&gt;24A324&lt;/string&gt; &lt;key&gt;DTSDKName&lt;/key&gt; &lt;string&gt;macosx15.0.internal&lt;/string&gt; &lt;key&gt;DTXcode&lt;/key&gt; &lt;string&gt;1620&lt;/string&gt; &lt;key&gt;DTXcodeBuild&lt;/key&gt; &lt;string&gt;16C5031c&lt;/string&gt; &lt;key&gt;LSBackgroundOnly&lt;/key&gt; &lt;true/&gt; &lt;key&gt;LSMinimumSystemVersion&lt;/key&gt; &lt;string&gt;13.0&lt;/string&gt; &lt;key&gt;NSAppTransportSecurity&lt;/key&gt; &lt;dict&gt; &lt;key&gt;NSAllowsArbitraryLoads&lt;/key&gt; &lt;true/&gt; &lt;/dict&gt; &lt;key&gt;NSAppleEventsUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSBluetoothAlwaysUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSCalendarsUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSCameraUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSContactsUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSDesktopFolderUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSDocumentsFolderUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSDownloadsFolderUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSFileProviderDomainUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSFileProviderPresenceUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSLocalNetworkUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSLocationUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSMicrophoneUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSMotionUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSNetworkVolumesUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSPhotoLibraryUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSRemindersUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSRemovableVolumesUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSSpeechRecognitionUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSSystemAdministrationUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;NSSystemExtensionUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;key&gt;OSBundleUsageDescription&lt;/key&gt; &lt;string&gt;Access is necessary for automated testing.&lt;/string&gt; &lt;/dict&gt; &lt;/plist&gt; Additionally, spctl --assess --type execute BoostBrowserUITests-Runner.app return an exit code of 0 so I assume that means it can launch just fine, and applications are allowed to be run from "anywhere" in System Settings. I've found the XCUIProtectedResource.localNetwork value, but it seems to only be accessible on iOS for some reason (FB17829325). I'm trying to figure out why this is happening on this machine so I can either fix our code or fix the machine. I have an Apple script that will allow it, but it's fiddly and I'd prefer to fix this the correct way either with the machine or with fixing our testing code.

I want to configure one aspect of my networking configuration (the QUIC keepalive interval). This only seems to be configurable via Network.framework’s nw_quic_set_keepalive_interval. Is there any way to apply this to a URLSession? Or do I need to implement the whole connection management myself using Network.framework?

I upgraded my Mac to Sequoia 15.4.1 an i hat to upgrade XCode to Version 16.3. I access a MQTT Broker by an sending an mosquitto_sub request to the Broker. Now its no longer possible the request fails i granted Network permission to my App

I'm seeing fully reproducible issues with URLSession on iOS 18.4 RC Simulator running from Xcode 16.3 RC. URLSession seems to get into a broken state after a second app run. The following sample succeeds in fetching the JSON on first app run but when the app is closed and ran again it fails with one of these errors: Error: Error Domain=NSURLErrorDomain Code=-1005 "The network connection was lost." Error: Error Domain=NSURLErrorDomain Code=-1001 "The request timed out." I'm wondering if this something related to my OS setup or is this due to internal URLSession changes in iOS 18.4. Already submitted as FB17006003. Sample code attached below: import SwiftUI @main struct NetworkIssue18_4App: App { var body: some Scene { WindowGroup { ContentView() } } } struct ContentView: View { @State private var message: String = "" var body: some View { VStack { Text(message) Button("Try Again") { Task { await fetch() } } } .task { await fetch() } } private func fetch() async { message = "Loading..." let url = URL(string: "https://poetrydb.org/title/Ozymandias/lines.json")! let session = URLSession.shared do { let response = try await session.data(from: url) print("Response: \(response)") message = "Success, data length: \(response.0.count)" } catch { print("Error: \(error)") message = "Error: \(error.localizedDescription)" } } }

We have a setup where the system uses proxy settings configured via a PAC file. We are investigating how NWConnection behaves inside a Network Extension (NETransparentProxyProvider) with a transparent proxy configuration based on this PAC file. Scenario: The browser makes a connection which the PAC file resolves as "DIRECT" (bypassing the proxy) Our Network Extension intercepts this traffic for analysis The extension creates a new connection using NWConnection to the original remote address. The issue: despite the PAC file’s "DIRECT" decision, NWConnection still respects the system proxy settings and routes the connection through the proxy. Our questions: Is it correct that NWConnection always uses the system proxy if configured ? Does setting preferNoProxies = true guarantee bypassing the system proxy? Additionally: Whitelisting IPs in the Network Extension to avoid interception is not a viable solution because IPs may correspond to multiple services, and the extension only sees IP addresses, not domains (e.g., we want to skip scanning meet.google.com traffic but still scan other Google services on the same IP range). Are there any recommended approaches or best practices to ensure that connections initiated from a Network Extension can truly bypass the proxy (for example, for specific IP ranges or domains)?

Hi! My project has the Local Push Connectivity entitlement for a feature we have requiring us to send low-latency critical notifications over a local, private Wi-Fi network. We have our NEAppPushProvider creating a SSE connection using the Network framework with our hardware running a server. The server sends a keep-alive message every second. On an iPhone 16 with iOS 18+, the connection is reliable and remains stable for hours, regardless of whether the iOS app is in the foreground, background, or killed. One of our QA engineers has been testing on an iPhone 13 running iOS 16, and has notice shortly after locking the phone, specifically when not connected to power the device seems to turn off the Wi-Fi radio. So when the server sends a notification, it is not received. About 30s later, it seems to be back on. This happens on regular intervals. When looking at our log data, the provider does seem to be getting stopped, then restarted shortly after. The reason code is NEProviderStopReasonNoNetworkAvailable, which further validates that the network is getting dropped by the device in regular intervals. My questions are: Were there possibly silent changes to the framework between iOS versions that could be the reason we're seeing inconsistent behavior? Is there a connection type we could use, instead of SSE, that would prevent the device from disconnecting and reconnecting to the Wi-Fi network? Is there an alternative approach to allow us to maintain a persistent network connection with the extension or app?

Our app supports live streaming (RTSP, RTMP, WebRTC) functionality. After updating to the 18.5 Developer Beta version, we’ve encountered an issue where streaming over LTE is not working for customers using SKT (SK Telecom) as their carrier. Upon investigation, it seems that a similar issue might be occurring with a streaming service app called "SOOP." I would appreciate it if you could share any information regarding this bug. Thank you.

I’m working on an iOS parental-control app that needs to block specific network traffic (e.g. certain domains or URLs). We’ve already obtained the Family Controls entitlement (since our app is explicitly a parental-control solution), but we do not use MDM to supervise devices. In testing, our NEFilterDataProvider extension only activates when the device is enrolled under a managed Family Controls profile. I am aware that we can use a PacketTunnel to achieve this but i was wondering if there is any simpler solution to this? Thanks for you time!

Our app is developed for iOS, but some users also run it on macOS (as an iOS app via Apple Silicon). The app requires local network permission, which works perfectly on iOS. Previously, the connection also worked fine on macOS, but since the recent macOS update, the app can no longer connect to our device. Additionally, our app on macOS doesn't prompt for local network permission at all, whereas it does on iOS. Is this a known issue with iOS apps running on macOS? Has anyone else experienced this problem, or is there a workaround? Any help would be appreciated!

Dear Developers, I would like to suggest an optimization for the logic governing the download and installation queue for app updates. Currently, when multiple applications are awaiting updates, the prioritization does not appear to consider the update payload size. My proposal is to implement a logic that prioritizes the download and installation of updates with a smaller delta size (fewer MB) before those with a larger delta. Practical Example: A 1MB update would be processed before a 500MB update, even if their arrival order in the queue was inverted. Potential Benefits: Perceived Speed Optimization (UX): Users would gain access to functional applications more quickly, especially in scenarios with multiple pending updates. Network Efficiency: In limited or intermittent bandwidth scenarios, completing smaller downloads first can reduce the chance of download failures and optimize network resource utilization. Device Resource Management: Frees up temporary storage and processing resources more rapidly for smaller updates. I believe this optimization would bring significant gains in terms of User Experience (UX) and the operational efficiency of the platform. Thank you for your attention and consideration. Sincerely,

ios構成プロファイルの制限のallowCloudPrivateRelayのプライベートリレーの制御とRelayペイロードの機能は関係がありますか？ それとも別々の機能でしょうか？ ↓ s there a relationship between the private relay control in the iOS configuration profile restriction allowCloudPrivateRelay and the functionality of the Relay payload? Or are they separate features?

I was excited to find out about Wi-Fi Aware in i[Pad]OS 26 and was eager to experiment with it. But after wiping and updating two devices (an iPhone 11 Pro and a 2018 11" iPad Pro) to Beta 1 I found out that neither of them support Wi-Fi Aware 🙁. What current and past iPhone and iPad models support Wi-Fi Aware? And is there a new UIRequiredDeviceCapabilities key for it, to indicate that an app requires a Wi-Fi Aware capable device?

Most apps perform ordinary network operations, like fetching an HTTP resource with URLSession and opening a TCP connection to a mail server with Network framework. These operations are not without their challenges, but they’re the well-trodden path. If your app performs ordinary networking, see TN3151 Choosing the right networking API for recommendations as to where to start. Some apps have extra-ordinary networking requirements. For example, apps that: Help the user configure a Wi-Fi accessory Require a connection to run over a specific interface Listen for incoming connections Building such an app is tricky because: Networking is hard in general. Apple devices support very dynamic networking, and your app has to work well in whatever environment it’s running in. Documentation for the APIs you need is tucked away in man pages and doc comments. In many cases you have to assemble these APIs in creative ways. If you’re developing an app with extra-ordinary networking requirements, this post is for you. Note If you have questions or comments about any of the topics discussed here, put them in a new thread here on DevForums. Make sure I see it by putting it in the App & System Services > Networking area. And feel free to add tags appropriate to the specific technology you’re using, like Foundation, CFNetwork, Network, or Network Extension. Links, Links, and More Links Each topic is covered in a separate post: The iOS Wi-Fi Lifecycle describes how iOS joins and leaves Wi-Fi networks. Understanding this is especially important if you’re building an app that works with a Wi-Fi accessory. Network Interface Concepts explains how Apple platforms manage network interfaces. If you’ve got this far, you definitely want to read this. Network Interface Techniques offers a high-level overview of some of the more common techniques you need when working with network interfaces. Network Interface APIs describes APIs and core techniques for working with network interfaces. It’s referenced by many other posts. Running an HTTP Request over WWAN explains why most apps should not force an HTTP request to run over WWAN, what they should do instead, and what to do if you really need that behaviour. If you’re building an iOS app with an embedded network server, see Showing Connection Information in an iOS Server for details on how to get the information to show to your user so they can connect to your server. Many folks run into trouble when they try to find the device’s IP address, or other seemingly simple things, like the name of the Wi-Fi interface. Don’t Try to Get the Device’s IP Address explains why these problems are hard, and offers alternative approaches that function correctly in all network environments. Similarly, folks also run into trouble when trying to get the host name. On Host Names explains why that’s more complex than you might think. If you’re working with broadcasts or multicasts, see Broadcasts and Multicasts, Hints and Tips. If you’re building an app that works with a Wi-Fi accessory, see Working with a Wi-Fi Accessory. If you’re trying to gather network interface statistics, see Network Interface Statistics. There are also some posts that are not part of this series but likely to be of interest if you’re working in this space: TN3179 Understanding local network privacy discusses the local network privacy feature. Calling BSD Sockets from Swift does what it says on the tin, that is, explains how to call BSD Sockets from Swift. When doing weird things with the network, you often find yourself having to use BSD Sockets, and that API is not easy to call from Swift. The code therein is primarily for the benefit of test projects, oh, and DevForums posts like these. TN3111 iOS Wi-Fi API overview is a critical resource if you’re doing Wi-Fi specific stuff on iOS. TLS For Accessory Developers tackles the tricky topic of how to communicate securely with a network-based accessory. A Peek Behind the NECP Curtain discusses NECP, a subsystem that control which programs have access to which network interfaces. Networking Resources has links to many other useful resources. Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com" Revision History 2025-07-31 Added a link to A Peek Behind the NECP Curtain. 2025-03-28 Added a link to On Host Names. 2025-01-16 Added a link to Broadcasts and Multicasts, Hints and Tips. Updated the local network privacy link to point to TN3179. Made other minor editorial changes. 2024-04-30 Added a link to Network Interface Statistics. 2023-09-14 Added a link to TLS For Accessory Developers. 2023-07-23 First posted.

Hi all, im trying to implement a per-app vpn in my network extension (packet tunnel with custom protocol), where only the traffic generated by my application should be routed trought my network extension. It is possible to accomplish that on a non managed or supervised device? Setting the routingMethod as .sourceApplication in NEPacketTunnelProvider is not possible as it is read-only, can it work trying overriding the var as a computed property? The documentation lack of examples. Thanks in advance! Love