I'm seeing weird behavior between my Mojave beta systems (and production systems) and the sporadic Captive Network Assistant (CNA).
It seems that Mojave's CNA is not always querying captive.apple.com and bringing up the captive portal splash screen when connecting.
If I run a tcpdump during the connections when this happens, I never see it try to query captive.apple.com via DNS and then attempt the HTTP access to it. However I DO see it querying a bunch of other things like push, icloud, etc. followed by https requests that are apparently happening in the background.
If I connect the same client to a different network that uses a portal, it will query captive.apple.com and I'll get the CNA splash screen (and portal).
Additionally, if my captive portal server tries to redirect to https, the splash screen MIGHT appear, but then goes to https://apple.com.
I don't get it.
I am trying to figure out how/when or why the end system sometimes queries and sometimes doesn't. It is affecting our customers who are expecting to see our captive portal login page upon connecting, but in most cases are not.
Many thanks.
