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Quad9 DOH HTTP/1.1 Retirement, December 15, 2025

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Re: Quad9 DOH HTTP/1.1 Retirement, December 15, 2025

#41

Post by josephcsible »

dev_l1x_be wrote: post #30
josephcsible wrote: post #28

Earlier quoted context omitted.

Because if you're on the kind of malicious network that's the reason to use encrypted DNS at all, then your connection attempts on port 853 will probably just get blocked wholesale. DoH is better since it looks the same as all other HTTPS traffic. And you can still block ad and scam domains with DoH. Either do so with a browser extension, in your hosts file, or with a local resolver that does the filtering and then u…

> And you can still block ad and scam domains with DoH. How? There are certain browsers that ignore your DNS settings and talk directly to DoH servers. How could I check what is that the browser requesting through a SSL session? Do you want me to spoof a cert and put it on a MITM node? These are my nameservers: nameserver 10.10.10.65 nameserver 10.10.10.66 If the browser plays along than talking to these is the safes…

AdGuard has a DoH server. Just configure your browser to use https://dns.adguard-dns.com/dns-query for it.

Re: Quad9 DOH HTTP/1.1 Retirement, December 15, 2025

#42

Post by 1vuio0pswjnm7 »

RFC 8484:

"5.2. HTTP/2

HTTP/2 [RFC7540] is the minimum RECOMMENDED version of HTTP for use with DoH."

One paper I read some years ago reported DoH is faster than DoT but for multiple queries in single TCP connection outside the browser I find that DoT is faster

I use a local forward proxy for queries with HTTP/2. (Using libnghttp2 is another alternative). In own case (YMMV) HTTP/2 is not signifcantly faster than using HTTP/1.1 pipelining

For me, streaming TCP queries with DoT blows DoH away

Re: Quad9 DOH HTTP/1.1 Retirement, December 15, 2025

#43

Post by Sohcahtoa82 »

EE84M3i wrote: post #37
hypeatei wrote: post #25

> However, we are reaching the end of life for the libraries and code that support HTTP/1.1 What libraries are ending support for HTTP/1.1? That seems like an extremely bad move and somewhat contrived.

HTTP versions less than 2 have serious unresolvable security issues related to http request/response smuggling and stream desynchronization. https://http1mustdie.com/

I have an alternative...

Rather than throwing HTTP/1.1 into the garbage can, why don't we throw Postel's Law [0] into the garbage where it belongs.

Every method of performing request smuggling relies on making an HTTP request that violates spec. A request that sends both Content-Length and Transfer-Encoding is invalid. Sending two Content-Lengths is invalid. Two Transfer-Encoding headers is allowed -- They should be treated as a comma-separated lists -- so allow them and treat them as such, or canonicalize them as a single header if you're transforming it to something downstream.

But for fuck's sake, there's literally no reason to accept requests that contain most of the methods that smuggling relies upon. Return a 400 Bad Request and move on. No legit client sends these invalid requests unless they have a bug, and it's not your job as a server to work around their bug.

[0] Aka, The Robustness Principle, "Be conservative in what you send, liberal in what you accept."

Re: Quad9 DOH HTTP/1.1 Retirement, December 15, 2025

#44

Post by wahern »

bawolff wrote: post #32
cenamus wrote: post #5

Earlier quoted context omitted.

http/2 surely not simpler?

I feel like securing against request smuggling is simpler with http/2. That is of course only one aspect. Ultimately though, its not like this is getting rid of http/1.1 in general, just DNS over http/1.1. I imagine the real reason is simply nobody was using it. Anyone not on the cutting edge is using normal dns, everyone else is using http/2 (or 3?) for dns. It is an extremely weird middle ground to use dns over htt…

Request smuggling is an issue when reverse proxying and multiplexing multiple front-end streams over a shared HTTP/1.1 connection on the backend. HTTP/2 on the front-end doesn't resolve that issue, though the exploit techniques are slightly different. In fact, HTTP/2 on the front-end is a deceptive solution to the problem because HTTP/2 is more complex (the binary framing doesn't save you, yet you still have to deal with unexpected headers--you can still send Content-Length headers, for example) and the exploits less intuitive.

HTTP/1.1 is a simpler protocol and easier to implement, even with chunked Transfer-Encoding and pipelining. (For one thing, there's no need to implement HPACK.) It's trying to build multiplexing tunnels across it that is problematic, because buggy or confused handling of the line-delimited framing between ostensibly trusted end point opens up opportunities for desync that, in a simple 1:1 situation, would just be a stupid bug, no different from any other protocol implementation bug.

Because HTTP/2 is more complicated, there's arguably more opportunities for classic memory safety bugs. Contrary common wisdom, there's not a meaningful difference between text and binary protocols in that regard; if anything, text-based protocols are more forgiving of bugs, which is why they tend to promote and ossify proliferation of protocol violations. I've written HTTP and RTSP/RTP stacks several times, including RTSP/RTP nested inside bonded HTTP connections (what Quicktime used to use back in the day). I've also implemented MIME message parsers. The biggest headache and opportunity for bugs, IME, is dealing with header bodies, specifically the various flavors of structured headers, and unfortunately HTTP/2 doesn't directly address that--you're still handed a blob to parse, same as HTTP/1.1 and MIME generally. HTTP/2 does partially address the header folding problem, but it's common to reject those in HTTP/1.x implementations, something you can't do in e-mail stacks, unfortunately.

Re: Quad9 DOH HTTP/1.1 Retirement, December 15, 2025

#45

Post by kassner »

ori_b wrote: post #35
jeroenhd wrote: post #18

Earlier quoted context omitted.

Thanks to the ossification of the internet, every new protocol or protocol extension needs to be over HTTPS. DoT works fine, it's supported on all kinds of operating systems even if they don't advertise it, but DoH arrived in browsers. Some shitty ISPs and terrible middleboxes also block DoT (though IMO that should be a reason to switch ISPs, not a reason to stop using DoT). On the hosting side, there are more option…

> Thanks to the ossification of the internet, every new protocol or protocol extension needs to be over HTTPS. If someone can tell you're using HTTPS instead of some other TLS-encrypted protocol, that means they've broken TLS.

I’d say nowadays 443/tcp is the only port that you’ll find open in any usable network, anything else is part of a corporate network whack-a-mole game. So while DoH and DoT traffic shouldn’t be distinguishable, 853/tcp is surely a weird port in the grand scheme of things.

Re: Quad9 DOH HTTP/1.1 Retirement, December 15, 2025

#46

Post by gfody »

bawolff wrote: post #33
gfody wrote: post #29

Earlier quoted context omitted.

I wonder too, for a DNS query do you ever need keepalive or chunked encoding? HTTP/1.0 seems appropriate and http2 seems overkill

DNS seems like exactly the scenario where you would want http2 (or http1.1 pipelining but nobody supports that). You need to make a bunch of dns requests at once, and dont want to have to wait a roundtrip to make the next one.

ok multiple requests makes sense for keepalive (or just support a "batch" query, it's http already why adhere so tightly to the udp protocol)

http/1.0 w/keepalive is common (amazon s3 for example) perfectly suitable simple protocol for this

Re: Quad9 DOH HTTP/1.1 Retirement, December 15, 2025

#47

Post by 1vuio0pswjnm7 »

zokier wrote: post #15
dev_l1x_be wrote: post #7

I never understood DOH over DOT. It makes sense if you want to hide DNS lookups so that people cannot block the DNS queries to ad and other scam networks.

DoQ is better than either dot/doh

DNSCurve is better than DoQ

Re: Quad9 DOH HTTP/1.1 Retirement, December 15, 2025

#48

Post by 1vuio0pswjnm7 »

wahern wrote: post #44
bawolff wrote: post #32

Earlier quoted context omitted.

I feel like securing against request smuggling is simpler with http/2. That is of course only one aspect. Ultimately though, its not like this is getting rid of http/1.1 in general, just DNS over http/1.1. I imagine the real reason is simply nobody was using it. Anyone not on the cutting edge is using normal dns, everyone else is using http/2 (or 3?) for dns. It is an extremely weird middle ground to use dns over htt…

Request smuggling is an issue when reverse proxying and multiplexing multiple front-end streams over a shared HTTP/1.1 connection on the backend. HTTP/2 on the front-end doesn't resolve that issue, though the exploit techniques are slightly different. In fact, HTTP/2 on the front-end is a deceptive solution to the problem because HTTP/2 is more complex (the binary framing doesn't save you, yet you still have to deal…

Argubaly, the complexity issue is not only the protocols themselves but also the fact that thanks to the companies pushing HTTP/2 and 3, there are now multiple (competing/overlapping/incompatible) protocols

For example, people passing requests received by HTTP/2 frontends to HTTP/1.1 backends

Re: Quad9 DOH HTTP/1.1 Retirement, December 15, 2025

#49

Post by zamadatix »

toast0 wrote: post #38
itopaloglu83 wrote: post #9

Earlier quoted context omitted.

DOH prevents malicious network providers from blocking DOT traffic to enforce their own DNS services for “efficiency” reasons. Most ISPs just want to sell your data and with encrypted client hello and DOH they’re losing visibility into what you’re doing.

Don't you just intercept traffic to well know recursive resolvers? And then drop packets to ports other than 53?

That's the beauty of DoH - you don't have to pick a resolver which uses a dedicated IP. You can even stand your own up behind a CDN and blocking it would mean blocking HTTPS traffic to the CDN.

Re: Quad9 DOH HTTP/1.1 Retirement, December 15, 2025

#50

Post by zamadatix »

dev_l1x_be wrote: post #30
josephcsible wrote: post #28

Earlier quoted context omitted.

Because if you're on the kind of malicious network that's the reason to use encrypted DNS at all, then your connection attempts on port 853 will probably just get blocked wholesale. DoH is better since it looks the same as all other HTTPS traffic. And you can still block ad and scam domains with DoH. Either do so with a browser extension, in your hosts file, or with a local resolver that does the filtering and then u…

> And you can still block ad and scam domains with DoH. How? There are certain browsers that ignore your DNS settings and talk directly to DoH servers. How could I check what is that the browser requesting through a SSL session? Do you want me to spoof a cert and put it on a MITM node? These are my nameservers: nameserver 10.10.10.65 nameserver 10.10.10.66 If the browser plays along than talking to these is the safes…

There are a plethora of ways to control whether the browser uses its own DoH or the system DNS. Some inside the browser itself, some in the machine's OS, and some from the local network.

You can also configure the browser to use your chosen DoH server directly, but this is often as much work as just telling the browser to use the system DNS server and setting that up as DoH anyways.

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