We have a macOS system extension with NETransparentProxyProvider which is able to intercept traffic and handle it. We also wanted to setup few search domains from our network extension. However, unlike PacketTunnelProvider, NEDNSSettings are completely ignored with NETransparentProxyProvider. So whats the best way to setup few DNS search domains when using NETransparentProxyProvider.

I'm developing a lighting control app for iOS that receives Art-Net (UDP port 6454) and sACN (UDP port 5568) packets from a lighting console and relays commands to BLE wristbands with LEDs. This is used in live event production — the participant locks their phone while in a show and expects lighting control to continue uninterrupted. The problem UDP receive stops reliably ~30 seconds after the screen locks. I understand this is by design - iOS suspends apps in the background. However, I'm trying to understand if any supported path exists for this use case. What I've already tried UIRequiresPersistentWiFi = true - helps with Wi-Fi association but doesn't prevent app suspension Silent AVAudioEngine loop with UIBackgroundModes: audio - keeps the app alive, works in testing, but risks App Store rejection and feels like an abuse of the audio background mode NWListener (Network framework) on the UDP port - same suspension behaviour Socket rebind on applicationWillEnterForeground - recovers after resume but doesn't prevent dropout What I'm asking Is there any supported background mode or entitlement for sustained UDP receive in a professional/enterprise context? (Similar to how VoIP apps get the voip background mode for sustained network activity.) Is the silent audio workaround considered acceptable for App Store distribution in a professional tools context, or will it be rejected? Is NEAppProxyProvider or another Network Extension a viable path, and if so does it require a special entitlement? Test project I have a minimal Xcode project (~130 lines) demonstrating the issue — NWListener on port 6454, packet counter, staleness timer, and silent audio toggle. I can share the test code. STEPS TO REPRODUCE In Xcode (one-time setup): Select the UDPBackgroundTest target → Signing & Capabilities → set your Team Plug in your iPhone → select it as the run destination Build & run — confirm packets appear on screen when you run 'send_test_udp.py' Lock the phone and observe the dropout Test: Open the app and run 'python3 send_test_udp.py 192.168.0.XXX' The app counts up the packages, they match the python output. 1 packet per second. lock screen & and wait 10 seconds unlock phone an see the numbers are 10 packets off

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.

When connecting to my M1 mac mini over ssh, certain programs are often unable to reach network destinations in the corporate LAN, although they can usually reach external addresses like www.apple.com. For example, a java program attempting to download from teamcity.dev.corp.com:8111 often fails like: java.net.NoRouteToHostException: No route to host Running the exact same command from the Apple Terminal program works like normal, simply connecting over ethernet on en0 to a TeamCity server inside the same building. Basic diagnostics from the ssh session do not show anything unusual: > traceroute teamcity.dev.corp.com traceroute to teamcity.dev.corp.com (10.21.4.1), 64 hops max, 40 byte packets 1 teamcity.dev.corp.com (10.21.4.1) 1.702 ms 0.409 ms 0.336 ms > route -n get teamcity.dev.corp.com route to: 10.21.4.1 destination: 10.21.4.1 interface: en0 flags: <UP,HOST,DONE,LLINFO,WASCLONED,IFSCOPE,IFREF> recvpipe sendpipe ssthresh rtt,msec rttvar hopcount mtu expire 0 0 0 0 0 0 1500 1194 > uname -a Darwin mac 25.1.0 Darwin Kernel Version 25.1.0: Mon Oct 20 19:32:47 PDT 2025; root:xnu-12377.41.6~2/RELEASE_ARM64_T8103 arm64 Similar problems occur in docker commands to a remote daemon ("no route to host" or "connection refused"): docker -H tcp://<ip>:<port> ... Most other programs are never affected by this problem. Are there other diagnostic steps that might reveal the cause?

Hello, I'm working on a Transparent Proxy and when the proxy is being stopped, I'm stopping all the flows by calling flow.closeWriteWithError(POSIXError(.ECANCELED)) flow.closeReadWithError(POSIXError(.ECANCELED)) Then all the flows are deallocated. When deallocating the flow the crash occurs: OS Version: macOS 14.1.2 (23B92) Exception Type: EXC_BREAKPOINT (SIGTRAP) Exception Codes: 0x0000000000000001, 0x000000018c2ef704 Termination Reason: Namespace SIGNAL, Code 5 Trace/BPT trap: 5 Terminating Process: exc handler [553] Thread 32 Crashed:: Dispatch queue: <my dispatch queue> 0 CoreFoundation 0x18c2ef704 CF_IS_OBJC + 76 1 CoreFoundation 0x18c23f61c CFErrorGetDomain + 32 2 libnetworkextension.dylib 0x19fe56a00 flow_error_to_errno + 28 3 libnetworkextension.dylib 0x19fe56920 flow_handle_pending_write_requests + 216 4 libnetworkextension.dylib 0x19fe5667c __NEFlowDeallocate + 380 5 CoreFoundation 0x18c2efe28 _CFRelease + 292 6 NetworkExtension 0x19d208390 -[NEAppProxyFlow dealloc] + 36 Is there any way to debug what is happening and if it's related to closing the flow with POSIXError? Thank you

Hello team, Would this mean that content filters intended for all browsing can only be implemented for managed devices using MDM? My goal would be to create a content filtering app for all users, regardless of if their device is managed/supervised. thanks.

Hi! I'm working on a solution (iOS 18) that uses Network Extensions PacketTunnelProvider and Content Filter. Currently I'm trying to integrate it with another extension – DNSProxyProvider. My goal is to process dns queries and use resolved ips and names for additional routing inside of the packet tunnel. I'm running into a major issue: whenever both VPN and DNS proxy are active simultaneously, the device completely loses internet connectivity — no traffic goes through, and DNS resolution seems to stop working entirely. I know about the mdm supervision requirement to use DNSProxyProvider and that's covered as I work with a managed device and install a DNS proxy profile, here's how its .mobileconfig file looks like: The DNS proxy itself works fine when working by itself (without VPN being turned on), as I implemented it that it successfully processes DNS packets flows while collecting information about domains etc, and everything works perfectly. Problems begin when using VPN at the same time. I'm aware that tunnel settings include dns related options that can affect this, but I haven't had much luck with tweaking them. Here's how they look right now for reference: let settings: NEPacketTunnelNetworkSettings = NEPacketTunnelNetworkSettings(tunnelRemoteAddress: "240.0.0.1") // let dnsSettings = NEDNSSettings(servers: "8.8.8.8,8.8.4.4".components(separatedBy: ",")) // dnsSettings.matchDomains = [""] // settings.dnsSettings = dnsSettings settings.proxySettings = nil /* ipv4 settings */ let ipv4Settings = NEIPv4Settings(addresses: ["240.0.0.2"], subnetMasks: ["255.255.255.0"]) ipv4Settings.includedRoutes = [NEIPv4Route.default()] settings.ipv4Settings = ipv4Settings /* MTU */ settings.mtu = 1500 return settings I've tried excluding some dns related ip routes and dns settings shenanigans but nothing. I haven't found any information that might suggest that using both of these extensions at the same time doesn't work, on the contrary, this page in the official documentation about the expected use of packet tunnel provider the expected use of packet tunnel provider, as it talks about the fact that you should not use it for interception of all of DNS traffic, as the use of DNSPRoxyProvider (or dns settings) are built for that, which in my mind, suggests that there should be no problem with using them both and just splitting the dns traffic handling to the proxy. Will be thankful for any help!

We have an iOS companion app that talks to our IoT device over the device’s own Wi‑Fi network (often with no internet). The app performs bi-directional, safety-critical duties over that link. We use an NEAppPushProvider extension so the handset can keep exchanging data while the UI is backgrounded. During testing we noticed that if the user backgrounds the app (still connected to the device’s Wi‑Fi) and opens Safari, the extension’s stop is invoked with NEProviderStopReason.unrecoverableNetworkChange / noNetworkAvailable, and iOS tears the extension down. Until the system restarts the extension (e.g. the user foregrounds our app again), the app cannot send/receive its safety-critical data. Questions: Is there a supported way to stop a safety-critical NEAppPushProvider from being terminated in this “background app → open Safari” scenario when the device remains on the same Wi‑Fi network (possibly without internet)? If not, is NEAppPushProvider the correct extension type for an always-on local-network use case like this, or is there another API we should be using? For safety-critical applications, can Apple grant entitlements/exemptions so the system does not terminate the extension when the user switches apps but stays on the local Wi‑Fi? Any guidance on the expected lifecycle or alternative patterns for safety-critical local connectivity would be greatly appreciated.

Hello all, Does anyone know how long it will take Apple to approve multicast entitlement approval after the Apple form is submitted? Any input would be appreciated. Thank you Allyson

Hello to all I have coded in swift a headless app, that launches 3 go microservices and itself. The app listens via unix domain sockets for commands from the microservices and executes different VPN related operations, using the NEVPNManager extension. Because there are certificates and VPN operations, the headless app and two Go microservices must run as root. The app and microservices run perfectly when I run in Xcode launching the swift app as root. However, I have been trying for some weeks already to modify the application so at startup it requests the password and runs as root or something similar, so all forked apps also run as root. I have not succeeded. I have tried many things, the last one was using SMApp but as the swift app is a headless app and not a CLI command app it can not be embedded. And CLI apps can not get the VPN entitlements. Can anybody please give me some pointers how can I launch the app so it requests the password and runs as root in background or what is the ideal framework here? thank you again.

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. WWDC 2025 Session 314 Get ahead with quantum-secure cryptography 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. Prepare your network environment for stricter security requirements support article — This is primarily of interest to folks developing management software, for example, an MDM server. 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.

My external device can generate a fixed Wi-Fi network. When I connect to this Wi-Fi using my iPhone 17 Pro Max (iOS version 26.0.1), and my app tries to establish a connection using the following method, this method returns -1 int connect(int, const struct sockaddr *, socklen_t) __DARWIN_ALIAS_C(connect); However, when I use other phones, such as iPhone 12, iPhone 8, iPhone 11, etc., to connect to this external device, the above method always returns successfully, with the parameters passed to the method remaining the same. I also tried resetting the network settings on the iPhone 17 Pro Max (iOS version 26.0.1), but it still cannot establish a connection.

Hi! I wrote an internal used backup command line tool which is in use since several years. Today I got an error while sending an email: “Failed: ioOnClosedChannel”. I assume that the latest macOS updates did break my app. On the server I use macOS 15.7 and on my development machine macOS 26. Here is the related code: private func sendMail() { var a : [Email.Attachment] = [] if self.imageData != nil { switch self.imageType { case .tiff: a.append(Email.Attachment(name: "Statistics.tif", contentType: #"image/tiff"#, contents: ByteBuffer(bytes: self.imageData!))) case .pdf: a.append(Email.Attachment(name: "Statistics.pdf", contentType: #"application/pdf"#, contents: ByteBuffer(bytes: self.imageData!))) case .unknown: fatalError("Unimplemented attachment type!") } } mailHtml = mailHtml.replacingOccurrences(of: "<br>", with: "<br>\n") let email = Email(sender: .init(name: "Backup", emailAddress: "SENDER@MYDOMAIN"), replyTo: nil, recipients: recipients, cc: [], bcc: [], subject: self.subject, body: .universal(plain: self.mailText, html: mailHtml), attachments: a) let evg = MultiThreadedEventLoopGroup(numberOfThreads: System.coreCount) let mailer = Mailer(group: evg, configuration: smtpConfig, transmissionLogger: nil) do { print("Sending mail... ", terminator: "") try mailer.send(email: email).wait() // <-- ERROR HERE Failed: ioOnClosedChannel print("done.") } catch { print("Failed: \(error)") } do { try evg.syncShutdownGracefully() } catch { print("Failed shutdown: \(error)") } } I use https://github.com/sersoft-gmbh/swift-smtp. Any clue about the reason of this error? TIA, GreatOm

I observed the following crash: Code Type: ARM-64 (Native) Parent Process: launchd [1] User ID: 0 Date/Time: 2025-10-07 13:48:29.082 OS Version: macOS 15.6 (24G84) Report Version: 12 Anonymous UUID: 8B651788-4B2E-7869-516B-1DA0D60F3744 Crashed Thread: 3 Dispatch queue: NEFlow queue Exception Type: EXC_BAD_ACCESS (SIGSEGV) Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000054 ... Thread 3 Crashed: Dispatch queue: NEFlow queue 0 libdispatch.dylib 0x000000019af6da34 dispatch_async + 192 1 libnetworkextension.dylib 0x00000001b0cf8580 __flow_startup_block_invoke.216 + 124 2 com.apple.NetworkExtension 0x00000001adf97da8 __88-[NEExtensionAppProxyProviderContext setInitialFlowDivertControlSocket:extraValidation:]_block_invoke.90 + 860 3 libnetworkextension.dylib 0x00000001b0cf8140 __flow_startup_block_invoke.214 + 172 4 libdispatch.dylib 0x000000019af67b2c _dispatch_call_block_and_release + 32 5 libdispatch.dylib 0x000000019af8185c _dispatch_client_callout + 16 6 libdispatch.dylib 0x000000019af70350 _dispatch_lane_serial_drain + 740 7 libdispatch.dylib 0x000000019af70e2c _dispatch_lane_invoke + 388 8 libdispatch.dylib 0x000000019af7b264 _dispatch_root_queue_drain_deferred_wlh + 292 9 libdispatch.dylib 0x000000019af7aae8 _dispatch_workloop_worker_thread + 540 10 libsystem_pthread.dylib 0x000000019b11be64 _pthread_wqthread + 292 11 libsystem_pthread.dylib 0x000000019b11ab74 start_wqthread + 8 ... It appears that the crash is caused by the flow director queue becoming NULL when dispatch_async is called (accessing address 0x0000000000000054). Meanwhile, my transparent proxy was still running. I'm wondering if this is a known issue or if anyone else has encountered the same problem. @eskimo

I am running a full-tunnel VPN using a Packet Tunnel Provider. During VPN setup, we configure DNS setting with specific DNS servers for all domains to be used by the tunnel. However, our project requires DNS resolution for every domain from both the VPN-provided DNS servers and the ISP’s DNS servers. When I attempt to use c-ares or other third-party libraries to resolve domains via the ISP DNS servers, these libraries only detect and use the VPN DNS servers instead. As a result, all queries fail. Is there a way on iOS to programmatically determine the ISP DNS servers while a full-tunnel VPN is active, or a system API that allows DNS queries to be explicitly resolved using the ISP’s DNS servers?

Hi, after upgrading to MacOS Sequoia, my connection to my local IP address does not work. The issue is with the PF (MacOS advanced firewall), as I confirmed that my local application works disabling it temporarily. Does anyone know how can I do to solve this problem? As APP developer, this is a big problem for me. Thanks in advance.

Have you ever encountered the issue where the Wi-Fi MAC address information can no longer be retrieved after I updated to iOS 26?

Hi, I am making a AI-Powered app that makes api requests to the openai API. However, for security, I set up a vercel backend that handles the API calls securely, while my frontend makes a call to my vercel-hosted https endpoint. Interestingly, whenever I try to make that call on my device, an iPhone, I get this error: Task <91AE4DE0-2845-4348-89B4-D3DD1CF51B65>.<10> finished with error [-1003] Error Domain=NSURLErrorDomain Code=-1003 "A server with the specified hostname could not be found." UserInfo={_kCFStreamErrorCodeKey=-72000, NSUnderlyingError=0x1435783f0 {Error Domain=kCFErrorDomainCFNetwork Code=-1003 "(null)" UserInfo={_kCFStreamErrorDomainKey=10, _kCFStreamErrorCodeKey=-72000, _NSURLErrorNWResolutionReportKey=Resolved 0 endpoints in 3ms using unknown from query, _NSURLErrorNWPathKey=satisfied (Path is satisfied), interface: pdp_ip0[lte], ipv4, ipv6, dns, expensive, uses cell}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <91AE4DE0-2845-4348-89B4-D3DD1CF51B65>.<10>, _NSURLErrorRelatedURLSessionTaskErrorKey=( "LocalDataTask <91AE4DE0-2845-4348-89B4-D3DD1CF51B65>.<10>" ), NSLocalizedDescription=A server with the specified hostname could not be found., NSErrorFailingURLStringKey=https://[my endpoint], NSErrorFailingURLKey=https://[my endpoint], _kCFStreamErrorDomainKey=10} I'm completely stuck because when I directly make https requests to other api's like openai's endpoint, without the proxy, it finds the server completely fine. Running my endpoint on terminal with curl also works as intended, as I see api key usages. But for some reason, on my project, it does not work. I've looked through almost every single post I could find online, but a lot all of the solutions are outdated and unhelpful. I'm willing to schedule a call, meeting, whatever to resolve this issue and get help more in depth as well.

Hello team, We are using below example https://github.com/apple/pir-service-example as a starting point to setup PIR server for our backend, but I am not really understanding what else we need in this example to configure OHTTP gateway. Any help will be appreciated.

I am developing an iOS application using NWPathMonitor for network connectivity monitoring. We discovered a reproducible issue where disabling and re-enabling WiFi triggers an unexpected network status sequence. ENVIRONMENT: iOS Version: 17.x Device: iPhone (various models tested) Network Framework: NWPathMonitor from iOS Network framework STEPS TO REPRODUCE: Device connected to WiFi normally Disable WiFi via Settings or Control Center Re-enable WiFi via Settings or Control Center EXPECTED BEHAVIOR: WiFi reconnects and NWPathMonitor reports stable satisfied status ACTUAL BEHAVIOR: T+0s: WiFi re-enables, NWPathMonitor reports path.status = .satisfied T+8s: NWPathMonitor unexpectedly reports path.status = .unsatisfied with unsatisfiedReason = .notAvailable T+9-10s: NWPathMonitor reports path.status = .satisfied again Connection becomes stable afterward NETWORK PATH TIMELINE: T+0s: satisfied (IPv4: true, DNS: false) T+140ms: satisfied (IPv4: true, DNS: true) T+8.0s: unsatisfied (reason: notAvailable, no interfaces available) T+10.0s: satisfied (IPv4: true, DNS: true) KEY OBSERVATIONS: Timing consistency: unsatisfied event always occurs ~8 seconds after reconnection resolution: "Reset Network Settings" eliminates this behavior TECHNICAL QUESTIONS: What causes the 8-second delayed unsatisfied status after WiFi re-enablement? Is this expected behavior that applications should handle? Why does reset network setting in iPhone fix this issue?