That weird dot is called root. Without it, a name is unqualified, with it the name is completely defined. That means that context is everything. Without the dot, a resolver might add the resolver's domain or parts of it, repeatedly.
Now, you and I know exactly what: host.example.co.uk is supposed to mean but without the trailing dot a resolver could try to look up host.example.co.uk.example.co.uk
Windows out of the box, if this happened would also try host.example.co.uk.example.co then host.example.co.uk.example and then host.example.co.uk.example, then host.example.co.uk. and get a result. However I never saw Windows actually try the first effort and I think the behaviour was designed to deal with large corp with DNS federated monstrosity Active Directories.
Your browser is probably toddling off to a DNS over https (DoH) server these days without your say so and canoodling with all sorts of ne'er do wells. Your DNS lookups are basic data - your ISP used to love seeing where you go. Your OS vendor (if you buy your OS) obviously can pass back "telemetry". Mr Google, doesn't own the desktop but does own the browser, so by ensuring you use "safe" DNS servers for your browser instead of whatever you have configured, its all good. All these shenanigans does make IT troubleshooting far more exciting than it used to be.
I shouldn't worry too much about trailing dots. You will almost certainly not be using the DNS servers you think you are. I get why DOH was invented and there is a good reason for some "civilians" to use it - ie a non IT specialist using a nasty wifi hotspot will be protected from some harm by their browser going home securely to do DNS lookups. However is it up to the browser vendor to trample all over the user's choice of Endpoint Security?
DNS is way more complicated than simply looking up addresses. Its about money these days (actually it always has been since around 2000) and there are now a lot of very opinionated mega corps who want to decide who profits off you.
You might actually be surprised, or at least I was, that browsers -- and typically worse, IoT junk, still generally respect the DNS server(s) served to them via DHCP or they use plain ol' 53 to the hardcoded Google/Cloudflare standards. Some (like the Facebook Portal) are tricky enough to try DNS over TLS, but insofar as my big-list-of-common-DNS-IPs in the block rule is accurate, nothing reaches out over DoH unless explicitly configured to do so.
Like you, however, I see the writing on the wall. Being able to easily see (and block) how these devices/operating systems/apps relentlessly and obsessively phone home to upload as much telemetry as they can get their hands on is not something these corporations want. Eventually, they will all just use your connection for the bandwidth and pass everything over a VPN to hardcoded endpoints.
I've spent over 20 years running DNS servers, web proxies etc. I also happily run quite a lot of IoT crap. I have two VLANs at home - THINGS and SEWER. SEWER is for stuff that really scares me! SEWER has layer 2 (MAC) isolation.
For a laugh, on my laptop (Arch BTW) I block one of my browsers from all external access except via a local Squid proxy with bump n splice - man in the middle, but at least I am the man.
In general I am an optimist. I think we are going through growing pains, akin to dealing with a teenager ("I hate you"). Mr Google and the other school bullies will be gradually brought into line and we will all be gradually dragged into the future. It may well not be as envisioned by anyone. However the climate is a bit of a snag and that might be more important.
We live in a time when my grand daughters are able to cavort on a Chinese media platform and multiple American ones to the entire world as an audience. They look pretty cool whilst doing it - they have media and make up skills and more. I used be able to flick beer mats or something.
The world is twisting and turning in front of our eyes and I for one am out of breath (ex smoker!)
Yes, but in the end unless they change the underlying transport (i.e. TCP/IP) to something that is not the Internet, you can still see that the traffic is happening and block the endpoint.
If the device doesn’t work after that, well, maybe I didn’t need it.
I agree with that, but there's always going to be exceptions like 'smart' TVs. I have a Roku-based one, and I accept that whatever service (Disney/Hulu/etc.) I connect to can track what I do on their app, but I don't consent to Roku themselves tracking every click I make, app I'm using, or setting I change. Plenty of people have pointed out this traffic to Roku on their support forums, and AFAIK, they've never come clean as to what, exactly, they track.
Just because I let someone sleep on my couch doesn't mean I accept that they sneak into my bathroom and watch me shower.
That weird dot is called root. Without it, a name is unqualified, with it the name is completely defined. That means that context is everything. Without the dot, a resolver might add the resolver's domain or parts of it, repeatedly.
Now, you and I know exactly what: host.example.co.uk is supposed to mean but without the trailing dot a resolver could try to look up host.example.co.uk.example.co.uk
Windows out of the box, if this happened would also try host.example.co.uk.example.co then host.example.co.uk.example and then host.example.co.uk.example, then host.example.co.uk. and get a result. However I never saw Windows actually try the first effort and I think the behaviour was designed to deal with large corp with DNS federated monstrosity Active Directories.
Your browser is probably toddling off to a DNS over https (DoH) server these days without your say so and canoodling with all sorts of ne'er do wells. Your DNS lookups are basic data - your ISP used to love seeing where you go. Your OS vendor (if you buy your OS) obviously can pass back "telemetry". Mr Google, doesn't own the desktop but does own the browser, so by ensuring you use "safe" DNS servers for your browser instead of whatever you have configured, its all good. All these shenanigans does make IT troubleshooting far more exciting than it used to be.
I shouldn't worry too much about trailing dots. You will almost certainly not be using the DNS servers you think you are. I get why DOH was invented and there is a good reason for some "civilians" to use it - ie a non IT specialist using a nasty wifi hotspot will be protected from some harm by their browser going home securely to do DNS lookups. However is it up to the browser vendor to trample all over the user's choice of Endpoint Security?
DNS is way more complicated than simply looking up addresses. Its about money these days (actually it always has been since around 2000) and there are now a lot of very opinionated mega corps who want to decide who profits off you.