BigSur 11.5 Beta breaks NWConnection

not able to browse anymore although appproxy device

If I am reading this correctly, NWConnection is not broken in macOS 11.5 Beta but you are instead seeing variable network speeds through your provider where NWConnection is used. Is that correct?

It is not only network speed drop, but after some time, no network access anymore (I am capturing tcp 80/443 outbound traffic only). That was not the case with bigSur 11.4.

Are you using NEAppProxyProvider or are you using NETransparentProxyProvider?

I am using NEAppProxyProvider.

It is not only network speed drop, but after some time, no network access anymore (I am capturing tcp 80/443 outbound traffic only). That was not the case with bigSur 11.4.

Okay thank you for confirming. What I am trying to do here is suss out whether NWConnection is actually broken, but since it is running network traffic at all, then I suspect the issue you are seeing is somewhere else.

I ran a few tests today with NEAppProxyProvider with macOS 11.5 beta to proxy TCP traffic with NWConnection. I ran a proxy test for 15 minutes, proxying TCP traffic from video streaming sites and just general Safari traffic. Here are a few observations; Youtube traffic does not work the way you would expect with NEAppProxyProvider, it's very intermittent. This was a known bug and fixed with NETransparentProxyProvider. However, traffic from platforms like Twitch, Vimeo, and WWDC videos all still work fine with NEAppProxyProvider in macOS 11.5. So, if you are running into issues on macOS 11.5 with specific traffic like YouTube videos, try it with NETransparentProxyProvider. I did not experience any traffic slown-downs or delays other than Youtube traffic with NWConnection. Hope this helps in your investigation.

Matt Eaton
DTS Engineering, CoreOS
meaton3@apple.com

Hi Matt,

Confirmed that beginning from BigSur 11.4 the network loss issue happens: I tried on two macbook pro. They have no problem when at BigSur 11.3.1. But as soon as I upgrade them to 11.4, issue happens. Already use NETransparentProxy.

Can you help double confirm? You can use fast.com and speedtest.net which can show the symptom rather quick.

Thanks in advance.

And filter out only tcp 80 and 443 as I do.

Can you help double confirm?

No, I test on run different NETransparentProxyProvider tests on my 11.5 machine on a regular basis for post 443 traffic. If you feel that you have found a bug, you should open a bug report with a sysdiagnose.

Matt Eaton
DTS Engineering, CoreOS
meaton3@apple.com