macOS Mojave network issues when adding in proxy (pac file) ?

[Bernard_Huang]

Hi all,

This is a real head scratcher for me. I don't even know the wording I need to put into google search, so I need to ask it here. Hopefully some of you have experience this same thing. Or better still, have a solution.

Some of our Macbook fleet have been upgraded to macOS Mojave. They range from 10.14.2 to 10.14.5, depending if our end-users are diligent enough to keep up with versions.

Some (more than 50%) of our Mojave users are reporting that their network cuts out for no apparent reason. I have upgraded my work Macbook to 10.14.2, and I also experience this.

Being the Mac Admin, I have to investigate this. Here's my observation.
- My connection to internal network as well as external internet cuts out once a week. Others do report a lot more frequency, therefore it's a major concern.
- At the moment of network cut-out, I observe that my Google Chrome will have "Waiting for proxy" notification on bottom left corner of the Chrome window.
- When I get the network cut-out issue, I go to system preferences > network, and delete the existing network. Then re-adding the same network, and the problem goes away (at least for a while).
- After deleting and re-adding the network, I have to add in proxy settings (pac file) again to allow my Macbook to connect with external internet.

• The more I have to repeat doing this, I am now realising if I never re-add the proxy settings (pac file), my macOS Mojave network would work continuously. Only after I add in my proxy settings, that's when network issues start happening. But every user would need this proxy setting, who doesn't go to external internet to research things?

  Is there some sort of issue with Mojave and proxies?
  I know that Mojave (or since High Sierra 10.13.4) have introduce things such as kernel extensions and PPPC. Is there other things that would block proxy settings to be valid on a Mojave?

[ClassicII]

Do the dropouts only happen in safari ?

Does the website attempt to load but doesn't ?

[Bernard_Huang]

The dropout happens when I use Safari or Chrome.
When the dropout does happen, none of the network connection would work. Outlook (email exchange server), browser, network drive, etc, will just hang there waiting.

The website does attempt to load. In fact, if looking at the loading bar, it goes to about 25%, and it will keep hanging there until I give up, and I delete my current network connection and re-create it again.

And the last thing is I have checked console to see if there are any network error messages. There are no errors relating to network connectivity. I think it is because it really is just waiting for proxy. Why it is 'waiting for proxy' is my question and problem :(

[Aaron]

So I've been having issues lately as well. I just did a wireshark capture, and I can see that Safari is hitting the proxy, gets the 407 auth required response, at which point it's supposed to resubmit the request with credentials embedded. But for some reason it just stops and doesn't submit the credentials.

Unfortunately this seems the affect my Self Service as well, as the first thing it does when it opens is reach out to https://settings.crashlytics.com - so Self Service just hangs on load (is there a way to stop the Self Service from doing this?)

[Bernard_Huang]

Thanks @Aaron

Sad to say it brings me comfort that I am not the only one facing this issue. But still no closer to a solution :(