Launch a browser and enter this easy to remember all-numeric IP address:
1.1.1.1
in the address bar, and press return.
If you get the CloudFlare** splash page, your internet is working, but DNS lookup may not be working.
**CloudFlare is NOT part of the solution, they just own the easiest to remember all-numeric IP Address.
————
A system that requires a special login page may refuse to display on certain computers, including your Mac. This happens when the provider has aggressively blocked everything, including DNS-name (Internet Phone number) lookups.
To get any named thing on the internet, your Mac needs an IP address (internet Phone number). Without that, your well-crafted Mac Browser will not send out a request for web page data, because it does not know where to send it. Instead, it does not send anything out, and tells you (accurately) it can not connect.
The Provider wants you to send out a web page request, so that they can intercept that request, and present their login credentials page as a substitute web page for the one you requested. But the Provider will not allow you to do any DNS accesses to look up anything.
To get around this impasse, you type ANY “real, live” all-numeric IP address directly into your browser. That generates a web page request for the Provider to intercept and send you their login page.
Once logged in, the Provider typically allows all traffic to pass, including DNS lookup requests.
1.1.1.1 is the easiest to remember all-numeric IP address, that reliably answers with a splash page. You could use Apple's IP address, but that changes from time to time. You could use google's IP address, or any other IP address you prefer and can remember, (because, no lookups).
[in my option] this is NOT a defect of the Mac. A Web Browser should not send a packet onto the Internet without a known IP address as its destination. [Speculating] perhaps Windows computers insert a default address like Microsoft's address instead.
[I my opinion] this is a defect in the setup of the Provider's network, which SHOULD allow DNS lookups for the reasons I have stated above. That this defect mostly blocks Macs is merely a coincidence.
