@drivesitfar DNS stands for Domain Name Server — it's a part of the internet. Basically it's a server (computer) somewhere that helps look up the websites you are requesting. So when you type in a human-readable URL like
www.google.com, your router sends a request to a DNS server to figure out what the IP address of the website you are requesting is. Because computers and websites are identified by IP addresses (the string numbers that looks like 192.62.346.34).
But really when you enter a URL, the request doesn't immediately get looked up as the website IP itself, rather it goes through a chain of DNS servers to find the correct IP and serve you the website. All of this happens in milliseconds.
And... this doesn't just happen when YOU type something in the search bar.
Any internet-connected device in your home is likely making many external web requests per day. And they all go through DNS.
Your ISP (internet service provider) likely has their own DNS servers they gave you. But there are
many public DNS servers available across the internet. Many people don't know that they can
choose which DNS server they'd like to use. Google, for example, provides public DNS servers. Why might you want to choose your own? Some companies are more committed to running secure servers, not selling your data, not serving you targeted ads, etc. And like the ones
@Denwood and
@zanyad mentioned, some DNS servers can also provide a filtering function for privacy or blocking types of content. For example, let's say you search a certain website, and the DNS server blocks the request. This can be true for ads... or other nefarious sites and content.
I was not aware of the Cloudflare specialty servers, but that tracks.
Again, there are many out there.
Personally, I run an Adguard Plus extension on my Home Assistant installation. So I enter my Home Assistant local IP as my DNS in my router, and all local traffic goes through that Home Assistant machine, which then reaches out to a special Adguard DNS server that has some built-in protections. I've also enabled a number of blacklists to block malware and ads. It's great because I don't have to install any clunky ad-blocking software on my client devices, but the Home Assistant computer "checks" all the traffic.
Just to give you an idea of how many external web requests are happing in my house, today it's been 54,883 requests, with around 30% of those requests being blocked and never being resolved. I presume the blocked traffic is mostly ads.
