For most internet users, web browser queries are the only hand-crafted DNS queries they make (except I suppose for their ISP mail servers but they are a set-up once thing), so there is relatively little wrong with breaking all their DNS queries to missing domains.
You're right about the RFCs and I think I made my point badly: I'm not saying ISPs should interpret them any way they like, I'm saying that they deal with a commercial reality and real end-users who just want things to work, and that sometimes the best is the enemy of the good.
In reality, a technically incorrect DNS server can easily work better (help them get their stuff done) for a naive user than a conforming one. Believing anything else is just geek self-delusion.
The right way to solve this is to improve browsers so that NXDOMAIN causes them to show a search page—which is exactly what they have started doing, so hopefully ISPs will stop doing this in future.
"commercial reality" appears to be "if we can make money from this then lets do it, and RFCs be damned". If we accept that ISPs can interpret RFCs any way they chose, then I propose a new interpretation of RFC 793 (TCP).
Specifically, whereas formerly the TCP protocol was a request for a connection between two computers, I am now going to interpret the four byte destination address as follows:
"Customer provides this information to us for use as we see fit. We may, if we so choose, route the packets to this address, or we may choose to route it somewhere else, including our own servers, or to a Value Added provider of our choice."
After all, consumers don't know about TCP do they? So its quite alright to define TCP as whatever the fuck we want, and therefore do, entirely legally, whatever we want with that "communication". Right? There's relatively little wrong with that right? I'm sure Google does a better job of search than your little start-up, so its in the customers best interest.
Same for all telephony traffic too. If we want to route it via the local gestapo we don't need a wiretap warrant for that: we just interpret RFC 3261 (Session Initiation Protocol) our own way. After all, who says these bytes arriving at our router have any meaning at all?
You're right about the RFCs and I think I made my point badly: I'm not saying ISPs should interpret them any way they like, I'm saying that they deal with a commercial reality and real end-users who just want things to work, and that sometimes the best is the enemy of the good.
In reality, a technically incorrect DNS server can easily work better (help them get their stuff done) for a naive user than a conforming one. Believing anything else is just geek self-delusion.
The right way to solve this is to improve browsers so that NXDOMAIN causes them to show a search page—which is exactly what they have started doing, so hopefully ISPs will stop doing this in future.