Questions about Website and redirects

One domain, four addresses

With www and without, each over http and over https: that makes four addresses. Every one of them can end up somewhere else, at your website, at an error message, or at a placeholder page from years back. In the best case all four lead to the same page, and three of them redirect to the fourth.

The A record or a CNAME decides which server answers at all. Whether that server then delivers the page or redirects is no longer in DNS. The host decides that.

Why a redirect is hard to track down

It can sit in three places: in DNS as the provider's forwarding service, in the host's control panel, or in the web server itself. A record on its own does not give away which of them is doing the work. Only the comparison shows it: what is in DNS, and what does the address actually answer? Put the two side by side and you see which of the three places somebody flipped the switch in, and with that, where it can be flipped back.

Then there is the SSL certificate: it only ever covers particular names. If the www is missing from it, the browser warns even though the website itself runs perfectly.

Who has the server, and who has the records

The address in DNS is a number, and a number tells you nothing. Who owns the server behind it only comes out in the name held for it in the reverse directory. That name does not have to belong to the same provider as the nameservers, and often enough it does not. So the host and whoever manages the records are two separate questions here, with two separate answers.

And when both happen to be in motion: a transfer is only through once the old state is nowhere to be found. As long as records point at two providers, chance decides which one applies. That can be read from the outside too.