Quic does not work with CF

Website, Application, Performance DNS & Network
1

Hello

If I set dns to let the domain pass through cloudflare then quic doesn’t work. (h2)

alt-svc: h3-27=":443"; ma=86400, h3-25=":443"; ma=86400, h3-24=":443"; ma=86400, h3-23=":443"; ma=86400

However, if I change the dns settings to bypass CF, it starts working (http/2+quic/46)

alt-svc: quic=":443"; ma=2592000; v=“43,46”, h3-Q043=":443"; ma=2592000, h3-Q046=":443"; ma=2592000, h3-Q050=":443"; ma=2592000, h3-25=":443"; ma=2592000, h3-27=":443"; ma=2592000

I have enabled HTTP/3 (with QUIC) in CF settings

Something else needs to be set up for quic to work with CF?

2 Likes
2

Domain?

3
4

According to Check if HTTP/3 is enabled - Geekflare Tools your site works just fine on HTTP 3. There are different flavours of HTTP 3/QUIC and Cloudflare might not support every available version but overall your site works fine on HTTP 3.

5

but when I look at the protocol in the browser, through CF every link I have h2 and if I turn off CF, each is h2/quic

6

For starters, QUIC is only relevant in an HTTP 3 context and not HTTP 2.

Your server might respond with different values, but the output you posted does refer to HTTP 3 and that automatically includes QUIC. As evident from the link, your site works fine on HTTP 3.

7

Sounds like your origin server might support QUIC i.e. if you use litespeed or h2o web servers. But Cloudflare doesn’t support QUIC, only HTTP/3 via h3-25 to h3-27 drafts

8

With support for HTTP 3 they implicitly support QUIC, as HTTP 3 is based on it

The origin might just support one of the revisions not supported by Cloudflare right now.

After HTTP 1.1 it all got a mess :smile:

9

FYI, HTTP/3 (over QUIC) via alt-svc h3-23 to h3-27 isn’t same thing as Google QUIC via alt-svc quic and h3-Qxxx

10

I didnt say it was. This is where the different revisions come in respectively Google’s original idea of QUIC.

The point I was trying to make is that HTTP 3 implicitly means QUIC. The version and revision mess is a different story.

1 Like
11

Yeah messy state in terms of terminology to differentiate everything :laughing:

12

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