There are of course outliers but most people I know in the field care as much about personal rights & freedom as anyone else. Maybe even a small bit more.
I'm guessing that's the reason.
its usually not nefarious, that is just the simpelest (and usually, not always) wrong explanation.
people who think this is not normal probarbly didnt experience what kind of shit u could find on the pre google pre monitored internet. for sure shit u do not want your kids to find. if u dont understand, then likely u dont have kids and very weird fetishes...
https://shkspr.mobi/blog/2021/03/advanced-network-error-sear...
https://dn.org/the-sitefinder-debacle-that-shook-the-interne...
Some carriers also passed info in these headers to be used to make billing calls to the Telco, such as subscribing to premium services with minimal (if any) consent from the user.
I got stung by this years ago. An ad for mobile ringtones showed up on some news site I visited on my phone, I scrolled past without clicking. Next minute I get a text telling me I've subscribed signed up to a (iirc) $25/month ringtone plan and that it'd show up on my phone bill. It took an hour on the phone to my carrier to block the charges and get a refund. The ringtone company kept messaging me for a year that I needed to contact them and "fix" the issue.
Even with free ringtones, I'd send myself about three if I got a new phone. These days, I just keep a copy of the Nokia dubstep ringtone on hand in case I turn the ringer on, but it doesn't happen.
"WHO THE F gave them the right to modify the data in my tcp session!!!!".
Spying on it I assumed but modifying one byte of it? A naively written edi that did not expect that would be completely destroyed.
Probably shouldn't have been so stupid for 15 years already by that point. There is no such thing as the right, there is only the ability.
If someone has the ability to do something, they will. Reputation, right & wrong, none of that actually exists or matters.
It's sort of an absurd question, the prevalence of such things by ISPs was the literal impetus for DoH and DoT.
This is a good reminder to login and take a look, I wouldn't put it past them to change the setting name and reset the default.
Netflix has always listed AT&T as their number one worst offender when it comes to net neutrality.
So, I always run VPNs that I can trust.
But the good news is that at least the majority (for now) is against it.
Even outside ideology, plain business sense makes ISPs not want to deal with censorship & co. It's work to do that, hence costs money. But there are also ISPs resisting out of ideology and civic duty.
If you've ever been hit with a "webpage isn't updating" issue when someone else can see it, often it's different DNS servers.
It's best to never use the ISP's DNS servers, regardless of the reason why they might do what they do.
But providers overwriting DNS packets regardless – this is the topic of the article :)
P.S.: And yes, there are ways around this like DNSsec etc.
Introducing what ISPs do with DNS information is helpful to understand how encompassing DNS self-hosting needs to be thought about - DNS requests are important to consider the appropriate encryption for.
From the homelab side, increasingly with the automated attacks on systems, it seems wise to keep all services off the internet directly and put it behind one or more service to keep them safe. From that perspective, setting up something like Tailscale can also help mitigate this kind of issue.
One of the reasons a variety of providers have been pushing for DoH is because DoH fully closes the risk of ISP MITM without needing individual site operators to do anything. This is why you're seeing folks like Firefox and Chrome enable DoH by default.
... by replacing it with Google/Cloudflare MITM with whom the user doesn't even have a business relationship or even shared jurisdiction.
Many ISPs in many countries are forced to do this for certain enforcement action that gets put upon them by their respective states for things such as age gating, censorship, monitoring, it varies state by state.
And to be clear this is in no way an endorsement of the practice, and I am confident no ISP WANTS to do this.
I am speaking here as the owner of a UK ISP (who does not currently do this).