This is profoundly weird.
We just changed ISPs, and I'm updating our installers to reflect that.
And I experienced some weirdness.
It seems that our new ISP has something called "web address error
redirect service," that's enabled by default.
This caused me some (as I said) profound weirdness, trying to test an
update to one of our installer programs. It pings our FTP server's URL,
to verify that it can find it, and failing that, it tries the IP address.
With my WinDoze box still on the old DNS addresses, and my Mac tied up
doing something else, I was getting the expected "not found" messages
when pinging from a WinDoze command line, or using a browser on WinDoze.
I didn't find out about the "web address error redirect service" until I
got my Mac (already on the new DNS) back, and tried to open test.test
from a browser, and got a page of "suggestions."
Until I disabled it, this "web address error redirect service" was
giving PING a resolution on intentionally nonexistent URLs.
Is there a better way, assuming nothing installed above the OS, to check
whether a domain is reachable, than by pinging it? A way that is immune
to this "web address error redirect service" (just in case some customer
actually leaves it turned on)?