This phenomenon is so popular it has its own section on the "DNS Hijacking" wikipedia page.

https://en.wikipedia.org/wiki/DNS_hijacking#Manipulation_by_...

Unless they explicitly say so, your ISP is not spending a boat-load of money running a DNS server for you to use because they're nice. They're not even doing it because you're paying them for a service. They're doing it because they can monetize the data and serve you ads.

They're doing it because it's been a standard ISP practice for years because most people don't run their own recursive resolver and have no skills to do so. End result is that to provide an internet connection, you have to also provide a DNS resolver, full stop. Monetizing and ads came later when business stopped caring about the RFCs.

> End result is that to provide an internet connection, you have to also provide a DNS resolver, full stop

Nope. You have to provide the address of a resolver, but that doesn't mean you have to run one yourself. There's nothing stopping the ISPs shipping a standard DHCP config that points their customers at (for example) 8.8.8.8, or 1.1.1.1, or whoever.

German Telekom does this, just get a german DSL link and you'll find out the joy of getting redirected to shitty search engines plastered with ads.

Has it been suggested by anyone yet that Google is pushing for DoH because those DNS-typo advertisers are a competitor to its ad/search hegemony and eliminating them as a business model helps Google's bottom line.

I am certain it's been suggested. But I can't see Google's motives I can only see its actions. If you do good things whatever the reasons the good things stay done while the reasons die with you.

A few minutes walk from me some people opened a gelato place. You go there, you buy some gelato. Nice. Warm summer evening, drop in, buy a cone, delicious. I am 100% certain that by selling me frozen desert they get money! Their plan may not specifically have focused on me enjoying this at all. And yet, since the effect is that I can enjoy desert that's exactly what I do, and I don't begrudge them their money.

I doubt it, from what I know, the money the ISPs make from typo-searching is barely noticable, mostly a leftover from when ads where valuable.

You can say anything Google does is because it ends up pushing its own ad model, but I don't think many users would actively want ad results to show up when you would regularly get a NXDOMAIN.

Most people use their ISP provided DNS should be the null hypothesis / status quo. I wouldnt expect someone to prove that claim. I would expect someone to prove the claim "most people change their DNS from the ISP default to google."

I thought they were questioning whether ISPs in general routinely hijack DNS. I've not heard of this happening in the UK, but haven't scoped around looking for it.

It was normal in the US for an ISP to return a "helpful" page when you entered a nonexistant domain. It sort of looked like a search results page. In reality it usually turned into a page of ads. Each ISP may have been different with the volume of actual search results they returned on the page.

I've seen things like that in the UK, too; it's certainly not a US-only practice.

Both of the major ISPs in my area do this. AT&T and Cox Communications I'm fairly certain Comcast and Verizon does this as well.