Network connections send and receive data using transport and security protocols.

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NWProtocolWebSocket: How to get the HTTP error?
I've managed to put together a WebSocket client in Swift using NWProtocolWebSocket (though the documentation does not make it easy.) The point I'm stuck on is how to get a meaningful error if the server rejects the HTTP request, for example with a 404 or 403 status. The error reported to my stateUpdateHandler is a low-level POSIXErrorCode(rawValue: 53): Software caused connection abort). Additionally, how can I add custom headers to the HTTP request, like authorization or cookies? (I'm kind of wondering whether good ol' NSURLSession would have been a better choice -- TN3151 says: "Unless you have a specific reason to use URLSession, use Network framework for new WebSocket code", but at this point I feel that's bad advice.)
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May ’26
Custom NCM device being disabled by macOS
I have a custom-developed USB NCM device for a networking use case. My device is successfully enumerated by macOS at the USB layer, and it issues a USB SET_INTERFACE(altsetting = 1) to enable the NCM layer, but sometimes (about 50% of the time), the Mac then issues a USB SET_INTERFACE(altsetting = 0), which disables the interface. It never issues a SET_INTERFACE(altsetting = 1) command to re-enable it. In Network settings, the device just stays in the "Disconnected" state forever. For context, the NCM specification says that all NCM devices must have two "alternate settings" at the USB interface level. Altsetting 0 is the default "disabled" startup state where no data endpoints are enabled, and altsetting 1 is the "enabled" state where data IN/OUT endpoints are enabled and packets can be transferred. The NCM spec also says that SET_INTERFACE(altsetting=0) can be used by the host to 'reset' the NCM layer of the device back to known settings. I suspect this is what the Mac is trying to do, though it only does it 50% of the time. The remainder of the time, the device stays in altsetting 1 and traffic works just fine. My question is, how can I get to the bottom of why the Mac is sometimes sending the SET_INTERFACE(altsetting=0) command or, if this behavior is usual, why is it not then re-enabling using SET_INTERFACE(altsetting=1) ? "log stream --info --debug" shows no information on this, and the NCM driver is a closed-source kernel extension so I have no visibility of what it's doing and why. I've sniffed the USB bus using a packet analyzer and can't see anything odd there (no timing issues or dropped packets etc). Any tips would be appreciated. I'm on Tahoe 26.4.1. I really don't want to develop a custom driver for this device and would prefer to operate with the native NCM driver.
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App Review Rejection Due to External Payment Script Not Loading in Review Environment (Toss Payments CDN)
Hello, I am currently experiencing an issue during the App Review process related to a third-party payment integration using Toss Payments. Our app loads a payment widget from an external script hosted at: https://js.tosspayments.com/v2/standard In our local and production environments, the payment module works without any issues. However, in the App Review environment, the script appears to fail to load or initialize properly, resulting in an "Unknown Error" during payment widget initialization. We suspect that the App Review environment may have network restrictions or firewall rules that block or limit access to this external CDN (AWS-based), preventing the script from being fetched. We have already: Verified that the script loads correctly in all non-review environments Submitted a video demonstrating the normal payment flow Contacted the payment provider, and they confirmed that there are no IP blocks or restrictions on their side My questions are: Does the App Review environment impose restrictions on external CDN domains or third-party scripts? If so, what is the recommended approach for handling payment SDKs that rely on external script loading? As a temporary workaround for review purposes, would it be acceptable to: Bypass the actual payment SDK Replace it with a mock or simplified flow (e.g., tapping the payment button immediately proceeds to a success screen) Restore the real payment integration after approval? We want to ensure compliance with App Store guidelines while also resolving this review-specific issue efficiently. Any guidance or similar experiences would be greatly appreciated. Thank you!
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Apr ’26
UITextField and UITextView abnormally popped up the network permission application interface
in iOS26.4, after installing the app for the first time, opening the app and clicking on the UITextField input box will trigger the system to pop up the network permission application interface. This issue did not exist before iOS 26.3, only in iOS 26.4. This is a fatal bug where the network permission request box should not pop up when the developer has not called the network related API.
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UDP Broadcast with Network
I'm relatively new to socket networking, and am migrating an older project from CocoaAsyncSocket to Swift's native Network. The project utilises GCDAsyncUdpSocket.enableBroadcast(_ flag: Bool), but I don't know how to replicate this in Network. How do I enable UDP Broadcast on NWConnection?
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Apr ’26
Kernel panics on M5 devices with network extension
Hello, We have a security solution which intercepts network traffic for inspection using a combination of Transparent Proxy Provider and Content filter. Lately we are seeing reports from the market that on M5 Macbooks and A18 Neos the system will kernel panic using our solution, even though it never happens on M1-M4 and no significant code changes were made in the mean time. All crashes seem to be related to an internal double free in the kernel: panic(cpu 0 caller 0xfffffe003bb68224): skmem_slab_free_locked: attempt to free invalid or already-freed obj 0xf2fffe29e15f2400 on skm 0xf6fffe2518aaa200 @skmem_slab.c:646 Debugger message: panic Memory ID: 0xff OS release type: User OS version: 25D2128 Kernel version: Darwin Kernel Version 25.3.0: Wed Jan 28 20:54:38 PST 2026; root:xnu-12377.91.3~2/RELEASE_ARM64_T6050 Additionally, from further log inspection, before panics we find some weird kernel messages which seem to be related to some DMA operations gone wrong in the network driver on some machines: 2026-03-30 14:11:21.779124+0300 0x30f2 Default 0x0 873 0 Arc: (Network) [com.apple.network:connection] [C9.1.1.1 IPv4#e5b4bb04:443 in_progress socket-flow (satisfied (Path is satisfied), interface: en0[802.11], ipv4, ipv6, dns, uses wifi, flow divert agg: 1, LQM: good)] event: flow:start_connect @0.075s 2026-03-30 14:11:21.780015+0300 0x1894 Default 0x0 0 0 kernel: (402262746): No more valid control units, disabling flow divert 2026-03-30 14:11:21.780017+0300 0x1894 Default 0x0 0 0 kernel: (402262746): Skipped all flow divert services, disabling flow divert 2026-03-30 14:11:21.780102+0300 0x1894 Default 0x0 0 0 kernel: SK[2]: flow_entry_alloc fe "0 proc kernel_task(0)Arc nx_port 1 flow_uuid D46E230E-B826-4E0A-8C59-4C4C8BF6AA60 flags 0x14120<CONNECTED,QOS_MARKING,EXT_PORT,EXT_FLOWID> ipver=4,src=<IPv4-redacted>.49703,dst=<IPv4-redacted>.443,proto=0x06 mask=0x0000003f,hash=0x04e0a750 tp_proto=0x06" 2026-03-30 14:11:21.780194+0300 0x1894 Default 0x0 0 0 kernel: tcp connect outgoing: [<IPv4-redacted>:49703<-><IPv4-redacted>:443] interface: en0 (skipped: 0) so_gencnt: 14634 t_state: SYN_SENT process: Arc:873 SYN in/out: 0/1 bytes in/out: 0/0 pkts in/out: 0/0 rtt: 0.0 ms rttvar: 250.0 ms base_rtt: 0 ms error: 0 so_error: 0 svc/tc: 0 flow: 0x9878386f 2026-03-30 14:11:21.934431+0300 0xed Default 0x0 0 0 kernel: Hit error condition (not panicking as we're in error handler): t8110dart <private> (dart-apcie0): invalid SID 2 TTBR access: level 1 table_index 0 page_offset 0x2 2026-03-30 14:11:21.934432+0300 0xed Default 0x0 0 0 kernel: [ 73.511690]: arm_cpu_init(): cpu 6 online 2026-03-30 14:11:21.934441+0300 0xed Default 0x0 0 0 kernel: [ 73.511696]: arm_cpu_init(): cpu 9 online 2026-03-30 14:11:21.934441+0300 0xed Default 0x0 0 0 kernel: [ 73.569033]: arm_cpu_init(): cpu 6 online 2026-03-30 14:11:21.934441+0300 0xed Default 0x0 0 0 kernel: [ 73.569038]: arm_cpu_init(): cpu 9 online 2026-03-30 14:11:21.934442+0300 0xed Default 0x0 0 0 kernel: [ 73.577453]: arm_cpu_init(): cpu 7 online 2026-03-30 14:11:21.934442+0300 0xed Default 0x0 0 0 kernel: [ 73.586328]: arm_cpu_init(): cpu 5 online 2026-03-30 14:11:21.934442+0300 0xed Default 0x0 0 0 kernel: [ 73.586332]: arm_cpu_init(): cpu 8 online 2026-03-30 14:11:21.934442+0300 0xed Default 0x0 0 0 kernel: [ 73.621392]: (dart-apcie0) AppleT8110DART::_fatalException: dart-apcie0 (<ptr>): DART DART SID exception ERROR_SID_SUMMARY 0x00003000 ERROR_ADDRESS 0x0000000000009800 2026-03-30 14:11:21.934443+0300 0xed Default 0x0 0 0 kernel: [ 73.621397]: Hit error condition (not panicking as we're in error handler): 2026-03-30 14:11:21.934443+0300 0xed Default 0x0 0 0 kernel: t8110dart <ptr> (dart-apcie0): invalid SID 2 TTBR access: level 1 table_index 0 page_offset 0x2Expect a `deadbeef` in the error messages below 2026-03-30 14:11:21.934452+0300 0xed Default 0x0 0 0 kernel: Expect a `deadbeef` in the error messages below 2026-03-30 14:11:21.934456+0300 0xed Default 0x0 0 0 kernel: (AppleEmbeddedPCIE) apcie[0:centauri-control]::_dartErrorHandler() InvalidPTE caused by read from address 0x9800 by SID 2 (RID 2:0:1/useCount 1/device <private>) 2026-03-30 14:11:21.934469+0300 0xed Default 0x0 0 0 kernel: (AppleT8110DART) Ignored dart-apcie0 (0xfbfffe18820b0000): DART(DART) error: SID 2 PTE invalid exception on read of DVA 0x9800 (SEG 0 PTE 0x2) ERROR_SID_SUMMARY 0x00003000 TIME 0x11242d43fd TTE 0xffffffffffffffff AXI_ID 0 We do not have any correlation between machines, usage pattern or installed applications. Uninstalling the network protection features seem to largely fix the issues, even though we have heard of crashes happening even in safe mode or with our network extension disabled from system settings. We weren't able to reproduce internally and it seems to happen completely random on client machines, but often enough to be disrupting. Can you tell us please if this is a known problem and if there's a workaround or what can we do to narrow it down? Thanks.
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`NEProxySettings.matchDomains` / `exceptionList` not working as expected in `NEPacketTunnelProvider` (domain-scoped proxy not applied, and exceptions not bypassed)
I’m working on an iOS Network Extension where a NEPacketTunnelProviderconfigures a local HTTP/HTTPS proxy usingNEPacketTunnelNetworkSettings.proxySettings. Per NEProxySettings.exceptionList docs: If the destination host name of an HTTP connection matches one of these patterns then the proxy settings will not be used for the connection. However, I’m seeing two distinct issues: Issue A (exception bypass not working): HTTPS traffic to a host that matches exceptionList still reaches the proxy. Issue B (domain-scoped proxy not applied): When matchDomains is set to match a specific domain (example: ["googlevideo.com"]), I still observe its traffic in some apps is not proxied. If I remove the domain from matchDomains, the same traffic is proxied. Environment OS: iOS (reproduced with 26.4 and other versions) Devices: Reproduced with several iPhones (likely iPads as well) Xcode: 26.3 Extension: NEPacketTunnelProvider Minimal Repro (code) This is the minimal configuration. Toggle between CONFIG A / CONFIG B to reproduce each issue. import NetworkExtension final class PacketTunnelProvider: NEPacketTunnelProvider { override func startTunnel( options: [String : NSObject]? = nil, completionHandler: @escaping (Error?) -> Void ) { let proxyPort = 12345 // proxy listening port let settings = NEPacketTunnelNetworkSettings(tunnelRemoteAddress: "8.8.8.8") let proxySettings = NEProxySettings() proxySettings.httpEnabled = true proxySettings.httpsEnabled = true proxySettings.httpServer = NEProxyServer(address: "1.2.3.4", port: proxyPort) // proxy listening address proxySettings.httpsServer = NEProxyServer(address: "1.2.3.4", port: proxyPort) // proxy listening address // CONFIG A: proxy all domains, but exclude some domains // proxySettings.matchDomains can be set to match all domains // proxySettings.exceptionList = ["*.cdninstagram.com", "cdninstagram.com"] // CONFIG B: proxy only a specific domain // proxySettings.matchDomains = ["googlevideo.com"] settings.proxySettings = proxySettings setTunnelNetworkSettings(settings) { error in completionHandler(error) } } } Repro steps Issue A (exceptionList bypass not working) Enable the VPN configuration and start the tunnel with CONFIG A (exceptionList = ["*.cdninstagram.com", "cdninstagram.com"]). Open the Instagram app to trigger HTTPS connections to *.cdninstagram.com Inspect proxy logs: cdninstagram.com traffic is still received by the proxy. Safari comparison: If I access URLs that trigger the same *.cdninstagram.com hosts from Safari, it can behave as expected. When the traffic is triggered from the Instagram app, the excluded host still reaches the proxy as CONNECT, which is unexpected. Issue B (matchDomains not applied for YouTube traffic) Start the tunnel with CONFIG B (matchDomains = ["googlevideo.com"]). Open the YouTube app and start playing a video (traffic typically targets *.googlevideo.com). Inspect proxy logs: googlevideo.com traffic is not received by the proxy. Remove the host from matchDomains and observe that googlevideo.com traffic is received by the proxy. Safari comparison: If I access a googlevideo.com host from Safari while matchDomains = ["googlevideo.com"], it behaves as expected (proxied). In contrast, the YouTube app’s googlevideo.com traffic is not proxied unless I match all domains. Expected Issue A Connections to *.cdninstagram.com in the Instagram app should not use the proxy and should not reach the local proxy server. Issue B With matchDomains = ["googlevideo.com"], traffic to *.googlevideo.com (YouTube video traffic) should be proxied and therefore reach the local proxy. Actual Issue A The local proxy still receives the request as: CONNECT scontent-mad1-1.cdninstagram.com:443 HTTP/1.1 So the bypass does not happen. Issue B With matchDomains = ["googlevideo.com"], I still observe googlevideo.com traffic in the YouTube app that is not delivered to the proxy. When all traffic is proxied, the same traffic is delivered to the proxy.
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Apr ’26
Understanding '.waiting' state in NWConnection.State for UDP
While going through the documentation for NWConnection, there seems to be state known as .waiting which means that the connection is waiting for a path change. For TCP, the state is understandable and can occur under some scenarios. But for the case of UDP, I have following queries: Why do we need .waiting state for the case of UDP? Even if we do need .waiting state for UDP, when all does this state occurs?
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Apr ’26
iOS 26.4 breaks when loading WkWebview domain subresources from a loopback localhost in-app GCDWebserver +self signed cert with TLSv1_ALERT_UNKNOWN_CA
Hello All, I have a app which has a WKWebview loading some code from a remote origin - https://my-company.example.com When WKWebview loads remote origin, that page does load some of the sub-resources from in-app localhost server (GCDWebserver), i.e. reach out to a loopback based in-app GCDWebserver, now to provide a secure context I had an existing setup with self signed cert, CORS and everything needed for https on localhost. And the sub-resources used to load fine from https localhost till 26.4 Starting with iOS 26.4 it started breaking with TLSv1_ALERT_UNKNOWN_CA Is there any known guidance for this? Technically as per w3c spec, localhost is considered secure context by default right? and no special things need to be done. But ios/Webkit seem to be different in this regard. Is this a known issue, and is there any mitigation here? I'll try to provide a sample app soon if possible.
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Apr ’26
Cellular not initializing on iPadOS 26.4 (resolved by network reset)
We are seeing an issue after updating iPads to iPadOS 26.4 where cellular service is lost until network settings are reset. Environment: Devices managed via Apple Business Manager and Microsoft Intune Carrier: Verizon Confirmed affected devices: iPad (9th generation) eSIM Behavior: After update, device shows no cellular service No prompt to re-activate or re-add the cellular plan The plan appears to still be present on the device Workaround observed: Resetting Network Settings restores service Notes: This does not appear to be a provisioning issue (no need to re-add eSIM) Behavior suggests the cellular/eSIM state may not be initializing correctly after update Toggling Cellular or Airplane mode has not yet been tested for service restoration. We have not yet confirmed whether devices using a physical SIM are affected Still gathering data on scope across additional iPad models Additional observation: We have not observed this behavior on iPhones (e.g., iPhone 16 on iOS 26.4 with LTE remains unaffected) Has anyone else observed similar behavior on iPadOS 26.4, particularly on managed devices or eSIM configurations?
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Apr ’26
Memory Leak in new structured concurrency Network Framework API's
After implementing the new structured concurrency API's for Network framework, we are noticing a few memory leaks in the Network framework when using API's like onViabilityUpdate and onBetterPathUpdate. Whenever a previously established connection is disconnected, the NWConnection object is never released by the Network framework when we use the 2 API's mentioned. Irrespective of what goes inside these handlers(or leave it empty), the connection object is leaking. If I comment out the handlers, there is no memory leak. Posting this here in the forum to understand if others have encountered similar issues and found a workaround? Raised a feedback assistant request with all the details and a sample app here: FB22339653
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Mar ’26
Enterprise Install for a TLS Inspection proxy
I’m working on a product that includes TLS inspection capability. TLS inspection using a local MitM requires installing a trusted root certificate which is then used to create masquerade certificates to intercept and forward TLS traffic through the proxy. For manual installation the end user is required to authenticate as an administrator to modify the trust settings on our internal CA’s root certificate. My question concerns the options for enterprise deployment using an MDM. We want the generated root certificate to be unique to each endpoint so that if a private key is compromised it can’t be used to intercept traffic anywhere else. We can install a “certificate trust” configuration profile from the MDM but this requires a base64 encoded string of the root certificate. In effect the MDM needs to obtain the certificate from the endpoint and then send it back in the form of a configuration profile. I’m not aware that MDMs like Jamf can be configured to do this directly so we’re looking for any other mechanism to have macOS trust a locally generated certificate via MDM based on some non endpoint-unique criteria? One option might be to use an external CA with a trusted certificate to sign an intermediate endpoint certificate but this creates a significant risk if the external trusted certificate were ever compromised. Is this a common industry practice? So my question remains is there a better way to trust our per endpoint root certificate via MDM without needing to install a unique per endpoint configuration profile?
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Mar ’26
Triggering “realtime” mode for peer-to-peer WiFi via awdl to fix jitter problems
This is a bit complicated to explain so bare with me. I am working on building an app that allows you to send real time video/camera captures from one Apple device to another. I am using a custom UDP protocol built on top of NWListener, NWBrowser, and NWConnection APIs. It works fine, but there are a few issues that seems to all be related to awdl: When transmitting via WiFi over the router (not using peer-to-peer), there are periodic interruptions when the wireless card on the device changes channels for awdl polling. This is resolved by changing the 5GHz WiFi channel on the router to channel 149 (or disabling AWDL altogether which is not really feasible). In order to work around number 1, I decided to build in an option to toggle/prefer peer-to-peer transmission in the app thinking that if everything goes over a peer-to-peer connection the jitter caused from the channel switching should go away. This also works, but with an important caveat. The default transmission is extremely choppy until you take an OS action that “elevates” the AWDL connection into “realtime” mode. I am using includePeerToPeer on the listener, browser, and connection as well as serviceClass interactiveVideo. For number 1, you can understand that asking users to change the channel on their router is not a great user experience, but the problem is the peer-to-peer connection workaround is also not great by default. For number 2, as an example of the behavior, I can send a stream from my Mac to my iPad over a peer-to-peer connection and it works but the video is very choppy until I move my cursor from my Mac to my iPad to trigger Universal Control. I captured the OS logs while doing this and can confirm that something happens to trigger “realtime” mode on the AWDL connection. After that, the streaming is totally smooth with zero latency. Some log samples: 2026-03-19 12:42:01.277968-0400 0x1ae294c Default 0x0 495 3 rapportd: (CoreUtils) [com.apple.rapport:CLinkD] Update client from UniversalControl:697 2026-03-19 12:42:01.278031-0400 0x1ae294c Default 0x0 495 0 rapportd: (CoreUtils) [com.apple.CoreUtils:AsyncCnx] CLinkCnx-6089: Connect start: 'CLink-ed3b9618b4e0._companion-link._tcp.local.%13' 2026-03-19 12:42:01.278149-0400 0x1ae294c Default 0x0 495 0 rapportd: (CoreUtils) [com.apple.CoreUtils:AsyncCnx] CLinkCnx-6089: Querying SRV CLink-ed3b9618b4e0._companion-link._tcp.local.%13 2026-03-19 12:42:01.279454-0400 0x1ae253a Info 0x0 382 0 wifip2pd: [com.apple.awdl:datapathInitiator] Created AWDLDatapathInitiator clink-ed3b9618b4e0._companion-link._tcp.local <To: 2e:f2:5a:15:76:52> 2026-03-19 12:42:01.279498-0400 0x1ae294c Default 0x0 495 0 rapportd: (CoreUtils) [com.apple.CoreUtils:AsyncCnx] CLinkCnx-6089: Resolving DNS f970afcc-1f1c-47af-a3f3-0236c9f9bbb0.local.%13 2026-03-19 12:42:01.279588-0400 0x1ae253a Default 0x0 382 0 wifip2pd: [com.apple.awdl:datapathInitiator] AWDLDatapathInitiator clink-ed3b9618b4e0._companion-link._tcp.local <To: 2e:f2:5a:15:76:52> was started 2026-03-19 12:42:01.282537-0400 0x1ae294c Default 0x0 495 0 rapportd: (Network) [com.apple.network:path] nw_path_evaluator_start [5C54D967-624D-4269-B080-6C7AE63218C7 IPv6#1e905043%awdl0.49154 generic, attribution: developer] path: satisfied (Path is satisfied), interface: awdl0[802.11], dns, uses wifi 2026-03-19 12:42:01.596450-0400 0x1ae253a Debug 0x0 382 0 wifip2pd: [com.apple.awdl:driver] Received event realtimeMode 2026-03-19 12:42:01.596589-0400 0x1ae253a Default 0x0 382 0 wifip2pd: [com.apple.awdl:interface] Realtime mode updated true I noticed that on iOS 26 and iPadOS 26 a realtime mode was added specifically to the Wi-Fi Aware API which I assume does what I want: https://developer.apple.com/documentation/wifiaware/waperformancemode/realtime, but I am looking for a solution that works with the existing network API and also on previous OS versions. I have already tried a lot of things, but is there any way to programmatically trigger “realtime” mode? For additional context, the goal here is to have extremely low latency that also works for gaming. The actual latency introduced in 1 is approximately 30-50ms around once a second… adding a buffer to the stream makes the video completely smooth, but the extra delay on the receiver end is not acceptable for this use case. Any help or ideas would be appreciated. I can’t easily share a reproduce case right now, and even if I could, getting multiple devices into the exact state along with the router configuration in order to reproduce is going to be pretty difficult anyway.
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Showing All Messages curl: (35) Recv failure: Connection reset by peer
Showing All Messages [!] Error installing FBSDKLoginKit [!] /usr/bin/curl -f -L -o /Volumes/workspace/tmp/d20260316-6574-ros9od/file.zip https://github.com/facebook/facebook-ios-sdk/releases/download/v18.0.2/FacebookSDK_Dynamic.xcframework.zip --create-dirs --netrc-optional --retry 2 -A 'CocoaPods/1.16.2 cocoapods-downloader/2.1' % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0 0 0 0 0 0 0 0 0 --:--:-- 0:00:01 --:--:-- 0 0 0 0 0 0 0 0 0 --:--:-- 0:00:02 --:--:-- 0 0 0 0 0 0 0 0 0 --:--:-- 0:00:03 --:--:-- 0 0 0 0 0 0 0 0 0 --:--:-- 0:00:04 --:--:-- 0 0 0 0 0 0 0 0 0 --:--:-- 0:00:05 --:--:-- 0 curl: (35) Recv failure: Connection reset by peer Command exited with non-zero exit-code: 1 Running ci_post_clone.sh script failed (exited with code 1). Executable scripts are run using the interpreter specified in the shebang line.
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Mar ’26
Bonjour Conformance Test WARNING in Multicast DNS SHARED REPLY TIMING resolution
Hello and Good day! We are conducting Bonjour Conformance Test (BCT) for Printer device. BCT result is PASSED but with warning in Multicast DNS, specifically, WARNING: SHARED REPLY TIMING - UNIFORM RANDOM REPLY TIME DISTRIBUTION Other Shared Reply Timing is passed: PASSED: MULTIPLE QUESTIONS - SHARED REPLY TIMING - UNIFORM RANDOM REPLY TIME DISTRIBUTION Environment: BCT Tool Version: 1.5.4 (15400) MacOS Sequioa 15.5 DUT Firmware : Linux Debian 9 Apple mDNSResponder 1790.80.10 Service types: _ipps._tcp, _uscans._tcp, _ipp._tcp, _uscan._tcp Router : NEC AtermWR8370N Setup: 1-to-1 [Mac->Router<-DUT connection] Based on debug.log, this is where WARNING occurs: NOTICE 2026-03-04 10:51:06.870187+0900 _shared_reply_timing 04103: Shared reply response times: min = 26ms, max = 114ms, avg = 65.50ms WARNING 2026-03-04 10:51:06.870361+0900 _shared_reply_timing 04136: 50 percent of the replies within the correct range fell in the interval 20ms and 46ms (should be close to 25%). PASSED (SHARED REPLY TIMING) In the same debug.log for MULTIPLE QUESTIONS - SHARED REPLY TIMING is PASSED: NOTICE 2026-03-04 10:52:29.912334+0900 _shared_reply_timing 04103: Shared reply response times: min = 22ms, max = 112ms, avg = 78.00ms DEBUG_2 2026-03-04 10:52:29.912849+0900 recv_packet 01997: received packet (558 bytes) PASSED (MULTIPLE QUESTIONS - SHARED REPLY TIMING) [Details] Looking at Bonjour_Conformance_Guideline.pdf https://download.developer.apple.com/Documentation/Bonjour_Conformance_Test_Guideline/Bonjour_Conformance_Guideline.pdf there were some differences: In 1.6.2 Expected Result: Test Result File of Test that All Tests Passed, this is not displayed: PASSED: SHARED REPLY TIMING - UNIFORM RANDOM REPLY TIME DISTRIBUTION And in II.8 Shared Reply Timing: (Ideally, 25% of the answers should fall in each 21ms quadrant of the range 20ms - 125ms.) and comparing to the debug.log, there was a discrepancy of the interval, because 20ms and 46ms is 26ms interval. From RFC6762 6. Responding, Ideal range is from 20ms-120ms Because of this, please advise on the questions below: I would like to know on the possible cause and resolution for these WARNINGS. And since in current BCT result, (Test result integrity signature is generated), I would like to know if this is acceptable for BCT certification. Thank you.
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Mar ’26
LiveCommunicationKit on watchOS: Displaying visual content during active call?
Our watchOS app is exploring adding audio VOIP calling capability using our in-home platform. We are using LiveCommunicationKit for this and have that all hooked up nicely in a proof of concept implementation. Our use case is primarily based around supporting end-users through various tasks with assistance from a remotely based expert. We would like for our platform to be able to display visual content on the watch's screen during the call – in other words, we would like to be able to treat this as a video call. LiveCommunicationKit fully supports all video-related flags on watchOS and doesn't appear to have any different symbol availability versus its iOS version. This high-quality thread (https://developer.apple.com/forums/thread/798090) from a DTS engineer suggests that our use case should be valid (i.e. whiteboarding apps) and that the system's response to an accepted income video call is to dismiss the LCK's incoming call screen and bring the target app to the foreground, allowing it to render its custom content. Unfortunately, on watchOS the system doesn't seem to treat a video call any differently from an audio call, and won't dismiss the system UI once it's answered. We fully realize that Apple Watch doesn't have a camera for outbound video, doesn't support VideoToolbox or other low-level video convenience libraries for simplified rendering and decoding, etc. That's not what we're worried about (yet). The documentation is at best unclear about whether LCK (or CallKit, for that matter) can hand off calls flagged as video-compatible according to how we think they should, which is passing foreground UI over to the app once the call has been accepted by the user. Can any Apple people shed some light on this? I recognize we are probably trying to do something not many people have before.
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Mar ’26
Network Framework: Choosing Interface Types for Browsing/ Advertising
I am using Network framework for connecting two iPad devices that are connected through LAN and has Wifi enabled. I have enabled peerToPeerIncluded. I would like to understand how the framework chooses the interface types for browsing and discovering devices. When I start a browser with browser.run or listener.run, does the browser and advertiser browse and listen on all available interface types? My concern is that if it does in only one interface, Is there a chance that the browser is browsing in one interface(Lets say WiredEthernet) and the listener is listening on another interface(Lets say AWDL) and they dont discover?
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195
Mar ’26
Recording a Packet Trace
I want to track down which part of an app contacts a given domain listed in its App Privacy Report. Following the instructions given here I am able to capture a packet trace, but traffic to the domain in question is encrypted using QUIC. Is there a way to insert e.g. mitmproxy into the capture process in order to get hold of the SSLKEYLOGFILE so that I can decrypt the traffic?
20
0
1.1k
May ’26
Get UDP/TCP Payload for NWConnections?
Is it somehow possible to get the transport layer (UDP and TCP) payload amounts for TLS or QUIC connections established via the Network framework? (From within the app itself that establishes the connections.) I am currently using the ntstat.h kernel socket calls, but I hope there is a simpler solution. With ntstat, I have not yet been able to observe a specific connection. I have to search for the connection I am looking in all (userspace) connections.
5
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164
Mar ’26
NWProtocolWebSocket: How to get the HTTP error?
I've managed to put together a WebSocket client in Swift using NWProtocolWebSocket (though the documentation does not make it easy.) The point I'm stuck on is how to get a meaningful error if the server rejects the HTTP request, for example with a 404 or 403 status. The error reported to my stateUpdateHandler is a low-level POSIXErrorCode(rawValue: 53): Software caused connection abort). Additionally, how can I add custom headers to the HTTP request, like authorization or cookies? (I'm kind of wondering whether good ol' NSURLSession would have been a better choice -- TN3151 says: "Unless you have a specific reason to use URLSession, use Network framework for new WebSocket code", but at this point I feel that's bad advice.)
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1
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232
Activity
May ’26
Custom NCM device being disabled by macOS
I have a custom-developed USB NCM device for a networking use case. My device is successfully enumerated by macOS at the USB layer, and it issues a USB SET_INTERFACE(altsetting = 1) to enable the NCM layer, but sometimes (about 50% of the time), the Mac then issues a USB SET_INTERFACE(altsetting = 0), which disables the interface. It never issues a SET_INTERFACE(altsetting = 1) command to re-enable it. In Network settings, the device just stays in the "Disconnected" state forever. For context, the NCM specification says that all NCM devices must have two "alternate settings" at the USB interface level. Altsetting 0 is the default "disabled" startup state where no data endpoints are enabled, and altsetting 1 is the "enabled" state where data IN/OUT endpoints are enabled and packets can be transferred. The NCM spec also says that SET_INTERFACE(altsetting=0) can be used by the host to 'reset' the NCM layer of the device back to known settings. I suspect this is what the Mac is trying to do, though it only does it 50% of the time. The remainder of the time, the device stays in altsetting 1 and traffic works just fine. My question is, how can I get to the bottom of why the Mac is sometimes sending the SET_INTERFACE(altsetting=0) command or, if this behavior is usual, why is it not then re-enabling using SET_INTERFACE(altsetting=1) ? "log stream --info --debug" shows no information on this, and the NCM driver is a closed-source kernel extension so I have no visibility of what it's doing and why. I've sniffed the USB bus using a packet analyzer and can't see anything odd there (no timing issues or dropped packets etc). Any tips would be appreciated. I'm on Tahoe 26.4.1. I really don't want to develop a custom driver for this device and would prefer to operate with the native NCM driver.
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9
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488
Activity
4w
App Review Rejection Due to External Payment Script Not Loading in Review Environment (Toss Payments CDN)
Hello, I am currently experiencing an issue during the App Review process related to a third-party payment integration using Toss Payments. Our app loads a payment widget from an external script hosted at: https://js.tosspayments.com/v2/standard In our local and production environments, the payment module works without any issues. However, in the App Review environment, the script appears to fail to load or initialize properly, resulting in an "Unknown Error" during payment widget initialization. We suspect that the App Review environment may have network restrictions or firewall rules that block or limit access to this external CDN (AWS-based), preventing the script from being fetched. We have already: Verified that the script loads correctly in all non-review environments Submitted a video demonstrating the normal payment flow Contacted the payment provider, and they confirmed that there are no IP blocks or restrictions on their side My questions are: Does the App Review environment impose restrictions on external CDN domains or third-party scripts? If so, what is the recommended approach for handling payment SDKs that rely on external script loading? As a temporary workaround for review purposes, would it be acceptable to: Bypass the actual payment SDK Replace it with a mock or simplified flow (e.g., tapping the payment button immediately proceeds to a success screen) Restore the real payment integration after approval? We want to ensure compliance with App Store guidelines while also resolving this review-specific issue efficiently. Any guidance or similar experiences would be greatly appreciated. Thank you!
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0
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110
Activity
Apr ’26
UITextField and UITextView abnormally popped up the network permission application interface
in iOS26.4, after installing the app for the first time, opening the app and clicking on the UITextField input box will trigger the system to pop up the network permission application interface. This issue did not exist before iOS 26.3, only in iOS 26.4. This is a fatal bug where the network permission request box should not pop up when the developer has not called the network related API.
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6
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0
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847
Activity
3d
UDP Broadcast with Network
I'm relatively new to socket networking, and am migrating an older project from CocoaAsyncSocket to Swift's native Network. The project utilises GCDAsyncUdpSocket.enableBroadcast(_ flag: Bool), but I don't know how to replicate this in Network. How do I enable UDP Broadcast on NWConnection?
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1
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162
Activity
Apr ’26
Kernel panics on M5 devices with network extension
Hello, We have a security solution which intercepts network traffic for inspection using a combination of Transparent Proxy Provider and Content filter. Lately we are seeing reports from the market that on M5 Macbooks and A18 Neos the system will kernel panic using our solution, even though it never happens on M1-M4 and no significant code changes were made in the mean time. All crashes seem to be related to an internal double free in the kernel: panic(cpu 0 caller 0xfffffe003bb68224): skmem_slab_free_locked: attempt to free invalid or already-freed obj 0xf2fffe29e15f2400 on skm 0xf6fffe2518aaa200 @skmem_slab.c:646 Debugger message: panic Memory ID: 0xff OS release type: User OS version: 25D2128 Kernel version: Darwin Kernel Version 25.3.0: Wed Jan 28 20:54:38 PST 2026; root:xnu-12377.91.3~2/RELEASE_ARM64_T6050 Additionally, from further log inspection, before panics we find some weird kernel messages which seem to be related to some DMA operations gone wrong in the network driver on some machines: 2026-03-30 14:11:21.779124+0300 0x30f2 Default 0x0 873 0 Arc: (Network) [com.apple.network:connection] [C9.1.1.1 IPv4#e5b4bb04:443 in_progress socket-flow (satisfied (Path is satisfied), interface: en0[802.11], ipv4, ipv6, dns, uses wifi, flow divert agg: 1, LQM: good)] event: flow:start_connect @0.075s 2026-03-30 14:11:21.780015+0300 0x1894 Default 0x0 0 0 kernel: (402262746): No more valid control units, disabling flow divert 2026-03-30 14:11:21.780017+0300 0x1894 Default 0x0 0 0 kernel: (402262746): Skipped all flow divert services, disabling flow divert 2026-03-30 14:11:21.780102+0300 0x1894 Default 0x0 0 0 kernel: SK[2]: flow_entry_alloc fe "0 proc kernel_task(0)Arc nx_port 1 flow_uuid D46E230E-B826-4E0A-8C59-4C4C8BF6AA60 flags 0x14120<CONNECTED,QOS_MARKING,EXT_PORT,EXT_FLOWID> ipver=4,src=<IPv4-redacted>.49703,dst=<IPv4-redacted>.443,proto=0x06 mask=0x0000003f,hash=0x04e0a750 tp_proto=0x06" 2026-03-30 14:11:21.780194+0300 0x1894 Default 0x0 0 0 kernel: tcp connect outgoing: [<IPv4-redacted>:49703<-><IPv4-redacted>:443] interface: en0 (skipped: 0) so_gencnt: 14634 t_state: SYN_SENT process: Arc:873 SYN in/out: 0/1 bytes in/out: 0/0 pkts in/out: 0/0 rtt: 0.0 ms rttvar: 250.0 ms base_rtt: 0 ms error: 0 so_error: 0 svc/tc: 0 flow: 0x9878386f 2026-03-30 14:11:21.934431+0300 0xed Default 0x0 0 0 kernel: Hit error condition (not panicking as we're in error handler): t8110dart <private> (dart-apcie0): invalid SID 2 TTBR access: level 1 table_index 0 page_offset 0x2 2026-03-30 14:11:21.934432+0300 0xed Default 0x0 0 0 kernel: [ 73.511690]: arm_cpu_init(): cpu 6 online 2026-03-30 14:11:21.934441+0300 0xed Default 0x0 0 0 kernel: [ 73.511696]: arm_cpu_init(): cpu 9 online 2026-03-30 14:11:21.934441+0300 0xed Default 0x0 0 0 kernel: [ 73.569033]: arm_cpu_init(): cpu 6 online 2026-03-30 14:11:21.934441+0300 0xed Default 0x0 0 0 kernel: [ 73.569038]: arm_cpu_init(): cpu 9 online 2026-03-30 14:11:21.934442+0300 0xed Default 0x0 0 0 kernel: [ 73.577453]: arm_cpu_init(): cpu 7 online 2026-03-30 14:11:21.934442+0300 0xed Default 0x0 0 0 kernel: [ 73.586328]: arm_cpu_init(): cpu 5 online 2026-03-30 14:11:21.934442+0300 0xed Default 0x0 0 0 kernel: [ 73.586332]: arm_cpu_init(): cpu 8 online 2026-03-30 14:11:21.934442+0300 0xed Default 0x0 0 0 kernel: [ 73.621392]: (dart-apcie0) AppleT8110DART::_fatalException: dart-apcie0 (<ptr>): DART DART SID exception ERROR_SID_SUMMARY 0x00003000 ERROR_ADDRESS 0x0000000000009800 2026-03-30 14:11:21.934443+0300 0xed Default 0x0 0 0 kernel: [ 73.621397]: Hit error condition (not panicking as we're in error handler): 2026-03-30 14:11:21.934443+0300 0xed Default 0x0 0 0 kernel: t8110dart <ptr> (dart-apcie0): invalid SID 2 TTBR access: level 1 table_index 0 page_offset 0x2Expect a `deadbeef` in the error messages below 2026-03-30 14:11:21.934452+0300 0xed Default 0x0 0 0 kernel: Expect a `deadbeef` in the error messages below 2026-03-30 14:11:21.934456+0300 0xed Default 0x0 0 0 kernel: (AppleEmbeddedPCIE) apcie[0:centauri-control]::_dartErrorHandler() InvalidPTE caused by read from address 0x9800 by SID 2 (RID 2:0:1/useCount 1/device <private>) 2026-03-30 14:11:21.934469+0300 0xed Default 0x0 0 0 kernel: (AppleT8110DART) Ignored dart-apcie0 (0xfbfffe18820b0000): DART(DART) error: SID 2 PTE invalid exception on read of DVA 0x9800 (SEG 0 PTE 0x2) ERROR_SID_SUMMARY 0x00003000 TIME 0x11242d43fd TTE 0xffffffffffffffff AXI_ID 0 We do not have any correlation between machines, usage pattern or installed applications. Uninstalling the network protection features seem to largely fix the issues, even though we have heard of crashes happening even in safe mode or with our network extension disabled from system settings. We weren't able to reproduce internally and it seems to happen completely random on client machines, but often enough to be disrupting. Can you tell us please if this is a known problem and if there's a workaround or what can we do to narrow it down? Thanks.
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36
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2
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3.9k
Activity
1d
`NEProxySettings.matchDomains` / `exceptionList` not working as expected in `NEPacketTunnelProvider` (domain-scoped proxy not applied, and exceptions not bypassed)
I’m working on an iOS Network Extension where a NEPacketTunnelProviderconfigures a local HTTP/HTTPS proxy usingNEPacketTunnelNetworkSettings.proxySettings. Per NEProxySettings.exceptionList docs: If the destination host name of an HTTP connection matches one of these patterns then the proxy settings will not be used for the connection. However, I’m seeing two distinct issues: Issue A (exception bypass not working): HTTPS traffic to a host that matches exceptionList still reaches the proxy. Issue B (domain-scoped proxy not applied): When matchDomains is set to match a specific domain (example: ["googlevideo.com"]), I still observe its traffic in some apps is not proxied. If I remove the domain from matchDomains, the same traffic is proxied. Environment OS: iOS (reproduced with 26.4 and other versions) Devices: Reproduced with several iPhones (likely iPads as well) Xcode: 26.3 Extension: NEPacketTunnelProvider Minimal Repro (code) This is the minimal configuration. Toggle between CONFIG A / CONFIG B to reproduce each issue. import NetworkExtension final class PacketTunnelProvider: NEPacketTunnelProvider { override func startTunnel( options: [String : NSObject]? = nil, completionHandler: @escaping (Error?) -> Void ) { let proxyPort = 12345 // proxy listening port let settings = NEPacketTunnelNetworkSettings(tunnelRemoteAddress: "8.8.8.8") let proxySettings = NEProxySettings() proxySettings.httpEnabled = true proxySettings.httpsEnabled = true proxySettings.httpServer = NEProxyServer(address: "1.2.3.4", port: proxyPort) // proxy listening address proxySettings.httpsServer = NEProxyServer(address: "1.2.3.4", port: proxyPort) // proxy listening address // CONFIG A: proxy all domains, but exclude some domains // proxySettings.matchDomains can be set to match all domains // proxySettings.exceptionList = ["*.cdninstagram.com", "cdninstagram.com"] // CONFIG B: proxy only a specific domain // proxySettings.matchDomains = ["googlevideo.com"] settings.proxySettings = proxySettings setTunnelNetworkSettings(settings) { error in completionHandler(error) } } } Repro steps Issue A (exceptionList bypass not working) Enable the VPN configuration and start the tunnel with CONFIG A (exceptionList = ["*.cdninstagram.com", "cdninstagram.com"]). Open the Instagram app to trigger HTTPS connections to *.cdninstagram.com Inspect proxy logs: cdninstagram.com traffic is still received by the proxy. Safari comparison: If I access URLs that trigger the same *.cdninstagram.com hosts from Safari, it can behave as expected. When the traffic is triggered from the Instagram app, the excluded host still reaches the proxy as CONNECT, which is unexpected. Issue B (matchDomains not applied for YouTube traffic) Start the tunnel with CONFIG B (matchDomains = ["googlevideo.com"]). Open the YouTube app and start playing a video (traffic typically targets *.googlevideo.com). Inspect proxy logs: googlevideo.com traffic is not received by the proxy. Remove the host from matchDomains and observe that googlevideo.com traffic is received by the proxy. Safari comparison: If I access a googlevideo.com host from Safari while matchDomains = ["googlevideo.com"], it behaves as expected (proxied). In contrast, the YouTube app’s googlevideo.com traffic is not proxied unless I match all domains. Expected Issue A Connections to *.cdninstagram.com in the Instagram app should not use the proxy and should not reach the local proxy server. Issue B With matchDomains = ["googlevideo.com"], traffic to *.googlevideo.com (YouTube video traffic) should be proxied and therefore reach the local proxy. Actual Issue A The local proxy still receives the request as: CONNECT scontent-mad1-1.cdninstagram.com:443 HTTP/1.1 So the bypass does not happen. Issue B With matchDomains = ["googlevideo.com"], I still observe googlevideo.com traffic in the YouTube app that is not delivered to the proxy. When all traffic is proxied, the same traffic is delivered to the proxy.
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1
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281
Activity
Apr ’26
Understanding '.waiting' state in NWConnection.State for UDP
While going through the documentation for NWConnection, there seems to be state known as .waiting which means that the connection is waiting for a path change. For TCP, the state is understandable and can occur under some scenarios. But for the case of UDP, I have following queries: Why do we need .waiting state for the case of UDP? Even if we do need .waiting state for UDP, when all does this state occurs?
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3
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0
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261
Activity
Apr ’26
iOS 26.4 breaks when loading WkWebview domain subresources from a loopback localhost in-app GCDWebserver +self signed cert with TLSv1_ALERT_UNKNOWN_CA
Hello All, I have a app which has a WKWebview loading some code from a remote origin - https://my-company.example.com When WKWebview loads remote origin, that page does load some of the sub-resources from in-app localhost server (GCDWebserver), i.e. reach out to a loopback based in-app GCDWebserver, now to provide a secure context I had an existing setup with self signed cert, CORS and everything needed for https on localhost. And the sub-resources used to load fine from https localhost till 26.4 Starting with iOS 26.4 it started breaking with TLSv1_ALERT_UNKNOWN_CA Is there any known guidance for this? Technically as per w3c spec, localhost is considered secure context by default right? and no special things need to be done. But ios/Webkit seem to be different in this regard. Is this a known issue, and is there any mitigation here? I'll try to provide a sample app soon if possible.
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1
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832
Activity
Apr ’26
Cellular not initializing on iPadOS 26.4 (resolved by network reset)
We are seeing an issue after updating iPads to iPadOS 26.4 where cellular service is lost until network settings are reset. Environment: Devices managed via Apple Business Manager and Microsoft Intune Carrier: Verizon Confirmed affected devices: iPad (9th generation) eSIM Behavior: After update, device shows no cellular service No prompt to re-activate or re-add the cellular plan The plan appears to still be present on the device Workaround observed: Resetting Network Settings restores service Notes: This does not appear to be a provisioning issue (no need to re-add eSIM) Behavior suggests the cellular/eSIM state may not be initializing correctly after update Toggling Cellular or Airplane mode has not yet been tested for service restoration. We have not yet confirmed whether devices using a physical SIM are affected Still gathering data on scope across additional iPad models Additional observation: We have not observed this behavior on iPhones (e.g., iPhone 16 on iOS 26.4 with LTE remains unaffected) Has anyone else observed similar behavior on iPadOS 26.4, particularly on managed devices or eSIM configurations?
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3
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1
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693
Activity
Apr ’26
Memory Leak in new structured concurrency Network Framework API's
After implementing the new structured concurrency API's for Network framework, we are noticing a few memory leaks in the Network framework when using API's like onViabilityUpdate and onBetterPathUpdate. Whenever a previously established connection is disconnected, the NWConnection object is never released by the Network framework when we use the 2 API's mentioned. Irrespective of what goes inside these handlers(or leave it empty), the connection object is leaking. If I comment out the handlers, there is no memory leak. Posting this here in the forum to understand if others have encountered similar issues and found a workaround? Raised a feedback assistant request with all the details and a sample app here: FB22339653
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1
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140
Activity
Mar ’26
Enterprise Install for a TLS Inspection proxy
I’m working on a product that includes TLS inspection capability. TLS inspection using a local MitM requires installing a trusted root certificate which is then used to create masquerade certificates to intercept and forward TLS traffic through the proxy. For manual installation the end user is required to authenticate as an administrator to modify the trust settings on our internal CA’s root certificate. My question concerns the options for enterprise deployment using an MDM. We want the generated root certificate to be unique to each endpoint so that if a private key is compromised it can’t be used to intercept traffic anywhere else. We can install a “certificate trust” configuration profile from the MDM but this requires a base64 encoded string of the root certificate. In effect the MDM needs to obtain the certificate from the endpoint and then send it back in the form of a configuration profile. I’m not aware that MDMs like Jamf can be configured to do this directly so we’re looking for any other mechanism to have macOS trust a locally generated certificate via MDM based on some non endpoint-unique criteria? One option might be to use an external CA with a trusted certificate to sign an intermediate endpoint certificate but this creates a significant risk if the external trusted certificate were ever compromised. Is this a common industry practice? So my question remains is there a better way to trust our per endpoint root certificate via MDM without needing to install a unique per endpoint configuration profile?
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6
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1.1k
Activity
Mar ’26
Triggering “realtime” mode for peer-to-peer WiFi via awdl to fix jitter problems
This is a bit complicated to explain so bare with me. I am working on building an app that allows you to send real time video/camera captures from one Apple device to another. I am using a custom UDP protocol built on top of NWListener, NWBrowser, and NWConnection APIs. It works fine, but there are a few issues that seems to all be related to awdl: When transmitting via WiFi over the router (not using peer-to-peer), there are periodic interruptions when the wireless card on the device changes channels for awdl polling. This is resolved by changing the 5GHz WiFi channel on the router to channel 149 (or disabling AWDL altogether which is not really feasible). In order to work around number 1, I decided to build in an option to toggle/prefer peer-to-peer transmission in the app thinking that if everything goes over a peer-to-peer connection the jitter caused from the channel switching should go away. This also works, but with an important caveat. The default transmission is extremely choppy until you take an OS action that “elevates” the AWDL connection into “realtime” mode. I am using includePeerToPeer on the listener, browser, and connection as well as serviceClass interactiveVideo. For number 1, you can understand that asking users to change the channel on their router is not a great user experience, but the problem is the peer-to-peer connection workaround is also not great by default. For number 2, as an example of the behavior, I can send a stream from my Mac to my iPad over a peer-to-peer connection and it works but the video is very choppy until I move my cursor from my Mac to my iPad to trigger Universal Control. I captured the OS logs while doing this and can confirm that something happens to trigger “realtime” mode on the AWDL connection. After that, the streaming is totally smooth with zero latency. Some log samples: 2026-03-19 12:42:01.277968-0400 0x1ae294c Default 0x0 495 3 rapportd: (CoreUtils) [com.apple.rapport:CLinkD] Update client from UniversalControl:697 2026-03-19 12:42:01.278031-0400 0x1ae294c Default 0x0 495 0 rapportd: (CoreUtils) [com.apple.CoreUtils:AsyncCnx] CLinkCnx-6089: Connect start: 'CLink-ed3b9618b4e0._companion-link._tcp.local.%13' 2026-03-19 12:42:01.278149-0400 0x1ae294c Default 0x0 495 0 rapportd: (CoreUtils) [com.apple.CoreUtils:AsyncCnx] CLinkCnx-6089: Querying SRV CLink-ed3b9618b4e0._companion-link._tcp.local.%13 2026-03-19 12:42:01.279454-0400 0x1ae253a Info 0x0 382 0 wifip2pd: [com.apple.awdl:datapathInitiator] Created AWDLDatapathInitiator clink-ed3b9618b4e0._companion-link._tcp.local <To: 2e:f2:5a:15:76:52> 2026-03-19 12:42:01.279498-0400 0x1ae294c Default 0x0 495 0 rapportd: (CoreUtils) [com.apple.CoreUtils:AsyncCnx] CLinkCnx-6089: Resolving DNS f970afcc-1f1c-47af-a3f3-0236c9f9bbb0.local.%13 2026-03-19 12:42:01.279588-0400 0x1ae253a Default 0x0 382 0 wifip2pd: [com.apple.awdl:datapathInitiator] AWDLDatapathInitiator clink-ed3b9618b4e0._companion-link._tcp.local <To: 2e:f2:5a:15:76:52> was started 2026-03-19 12:42:01.282537-0400 0x1ae294c Default 0x0 495 0 rapportd: (Network) [com.apple.network:path] nw_path_evaluator_start [5C54D967-624D-4269-B080-6C7AE63218C7 IPv6#1e905043%awdl0.49154 generic, attribution: developer] path: satisfied (Path is satisfied), interface: awdl0[802.11], dns, uses wifi 2026-03-19 12:42:01.596450-0400 0x1ae253a Debug 0x0 382 0 wifip2pd: [com.apple.awdl:driver] Received event realtimeMode 2026-03-19 12:42:01.596589-0400 0x1ae253a Default 0x0 382 0 wifip2pd: [com.apple.awdl:interface] Realtime mode updated true I noticed that on iOS 26 and iPadOS 26 a realtime mode was added specifically to the Wi-Fi Aware API which I assume does what I want: https://developer.apple.com/documentation/wifiaware/waperformancemode/realtime, but I am looking for a solution that works with the existing network API and also on previous OS versions. I have already tried a lot of things, but is there any way to programmatically trigger “realtime” mode? For additional context, the goal here is to have extremely low latency that also works for gaming. The actual latency introduced in 1 is approximately 30-50ms around once a second… adding a buffer to the stream makes the video completely smooth, but the extra delay on the receiver end is not acceptable for this use case. Any help or ideas would be appreciated. I can’t easily share a reproduce case right now, and even if I could, getting multiple devices into the exact state along with the router configuration in order to reproduce is going to be pretty difficult anyway.
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4
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300
Activity
2w
Ideal and Largest RDMA Burst Width
In macOS Tahoe 26.2 an RDMA capability was added for Thunderbolt-5 interfaces. This has been demonstrated to significantly decrease the latency and maintain bandwidth for "clustered" Apple Silicon devices with TB5. What is the ideal and the maximum RDMA burst width for transfers over RDMA-enabled Thunderbolt-5 interfaces?
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4
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749
Activity
Mar ’26
Showing All Messages curl: (35) Recv failure: Connection reset by peer
Showing All Messages [!] Error installing FBSDKLoginKit [!] /usr/bin/curl -f -L -o /Volumes/workspace/tmp/d20260316-6574-ros9od/file.zip https://github.com/facebook/facebook-ios-sdk/releases/download/v18.0.2/FacebookSDK_Dynamic.xcframework.zip --create-dirs --netrc-optional --retry 2 -A 'CocoaPods/1.16.2 cocoapods-downloader/2.1' % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0 0 0 0 0 0 0 0 0 --:--:-- 0:00:01 --:--:-- 0 0 0 0 0 0 0 0 0 --:--:-- 0:00:02 --:--:-- 0 0 0 0 0 0 0 0 0 --:--:-- 0:00:03 --:--:-- 0 0 0 0 0 0 0 0 0 --:--:-- 0:00:04 --:--:-- 0 0 0 0 0 0 0 0 0 --:--:-- 0:00:05 --:--:-- 0 curl: (35) Recv failure: Connection reset by peer Command exited with non-zero exit-code: 1 Running ci_post_clone.sh script failed (exited with code 1). Executable scripts are run using the interpreter specified in the shebang line.
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1
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308
Activity
Mar ’26
Bonjour Conformance Test WARNING in Multicast DNS SHARED REPLY TIMING resolution
Hello and Good day! We are conducting Bonjour Conformance Test (BCT) for Printer device. BCT result is PASSED but with warning in Multicast DNS, specifically, WARNING: SHARED REPLY TIMING - UNIFORM RANDOM REPLY TIME DISTRIBUTION Other Shared Reply Timing is passed: PASSED: MULTIPLE QUESTIONS - SHARED REPLY TIMING - UNIFORM RANDOM REPLY TIME DISTRIBUTION Environment: BCT Tool Version: 1.5.4 (15400) MacOS Sequioa 15.5 DUT Firmware : Linux Debian 9 Apple mDNSResponder 1790.80.10 Service types: _ipps._tcp, _uscans._tcp, _ipp._tcp, _uscan._tcp Router : NEC AtermWR8370N Setup: 1-to-1 [Mac->Router<-DUT connection] Based on debug.log, this is where WARNING occurs: NOTICE 2026-03-04 10:51:06.870187+0900 _shared_reply_timing 04103: Shared reply response times: min = 26ms, max = 114ms, avg = 65.50ms WARNING 2026-03-04 10:51:06.870361+0900 _shared_reply_timing 04136: 50 percent of the replies within the correct range fell in the interval 20ms and 46ms (should be close to 25%). PASSED (SHARED REPLY TIMING) In the same debug.log for MULTIPLE QUESTIONS - SHARED REPLY TIMING is PASSED: NOTICE 2026-03-04 10:52:29.912334+0900 _shared_reply_timing 04103: Shared reply response times: min = 22ms, max = 112ms, avg = 78.00ms DEBUG_2 2026-03-04 10:52:29.912849+0900 recv_packet 01997: received packet (558 bytes) PASSED (MULTIPLE QUESTIONS - SHARED REPLY TIMING) [Details] Looking at Bonjour_Conformance_Guideline.pdf https://download.developer.apple.com/Documentation/Bonjour_Conformance_Test_Guideline/Bonjour_Conformance_Guideline.pdf there were some differences: In 1.6.2 Expected Result: Test Result File of Test that All Tests Passed, this is not displayed: PASSED: SHARED REPLY TIMING - UNIFORM RANDOM REPLY TIME DISTRIBUTION And in II.8 Shared Reply Timing: (Ideally, 25% of the answers should fall in each 21ms quadrant of the range 20ms - 125ms.) and comparing to the debug.log, there was a discrepancy of the interval, because 20ms and 46ms is 26ms interval. From RFC6762 6. Responding, Ideal range is from 20ms-120ms Because of this, please advise on the questions below: I would like to know on the possible cause and resolution for these WARNINGS. And since in current BCT result, (Test result integrity signature is generated), I would like to know if this is acceptable for BCT certification. Thank you.
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9
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318
Activity
Mar ’26
LiveCommunicationKit on watchOS: Displaying visual content during active call?
Our watchOS app is exploring adding audio VOIP calling capability using our in-home platform. We are using LiveCommunicationKit for this and have that all hooked up nicely in a proof of concept implementation. Our use case is primarily based around supporting end-users through various tasks with assistance from a remotely based expert. We would like for our platform to be able to display visual content on the watch's screen during the call – in other words, we would like to be able to treat this as a video call. LiveCommunicationKit fully supports all video-related flags on watchOS and doesn't appear to have any different symbol availability versus its iOS version. This high-quality thread (https://developer.apple.com/forums/thread/798090) from a DTS engineer suggests that our use case should be valid (i.e. whiteboarding apps) and that the system's response to an accepted income video call is to dismiss the LCK's incoming call screen and bring the target app to the foreground, allowing it to render its custom content. Unfortunately, on watchOS the system doesn't seem to treat a video call any differently from an audio call, and won't dismiss the system UI once it's answered. We fully realize that Apple Watch doesn't have a camera for outbound video, doesn't support VideoToolbox or other low-level video convenience libraries for simplified rendering and decoding, etc. That's not what we're worried about (yet). The documentation is at best unclear about whether LCK (or CallKit, for that matter) can hand off calls flagged as video-compatible according to how we think they should, which is passing foreground UI over to the app once the call has been accepted by the user. Can any Apple people shed some light on this? I recognize we are probably trying to do something not many people have before.
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2
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250
Activity
Mar ’26
Network Framework: Choosing Interface Types for Browsing/ Advertising
I am using Network framework for connecting two iPad devices that are connected through LAN and has Wifi enabled. I have enabled peerToPeerIncluded. I would like to understand how the framework chooses the interface types for browsing and discovering devices. When I start a browser with browser.run or listener.run, does the browser and advertiser browse and listen on all available interface types? My concern is that if it does in only one interface, Is there a chance that the browser is browsing in one interface(Lets say WiredEthernet) and the listener is listening on another interface(Lets say AWDL) and they dont discover?
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4
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195
Activity
Mar ’26
Recording a Packet Trace
I want to track down which part of an app contacts a given domain listed in its App Privacy Report. Following the instructions given here I am able to capture a packet trace, but traffic to the domain in question is encrypted using QUIC. Is there a way to insert e.g. mitmproxy into the capture process in order to get hold of the SSLKEYLOGFILE so that I can decrypt the traffic?
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20
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1.1k
Activity
May ’26
Get UDP/TCP Payload for NWConnections?
Is it somehow possible to get the transport layer (UDP and TCP) payload amounts for TLS or QUIC connections established via the Network framework? (From within the app itself that establishes the connections.) I am currently using the ntstat.h kernel socket calls, but I hope there is a simpler solution. With ntstat, I have not yet been able to observe a specific connection. I have to search for the connection I am looking in all (userspace) connections.
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5
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164
Activity
Mar ’26