For Workers & Pages, what is the name of the domain?
l2d.wakamo.top
What is the issue or error you’re encountering
The R2 custom domains do not support HTTP/3
What steps have you taken to resolve the issue?
I found a release log(Release-notes · Cloudflare R2 docs) of R2. It said the domains support HTTP2 since 2023. However nothing is related to HTTP3.
What are the steps to reproduce the issue?
Add a custom domain
Try to access it via HTTP/3 (curl —http3-only -I)
Actually I found a alt-svc header which means it should support QUIC, but it does not. All QUIC connections stuck on initial state. I tried to re-add the custom domain. QUIC works for only few seconds. Then I cannot connect to it via QUIC unless I re-add the domain again.
Seems it is an error. If it does not support QUIC completely, alt-svc header should not appear.
All other sites in this zone works fine with QUIC.
The S3 API (r2.cloudflarestorage.com) is HTTP/1.1 only (S3 Protocol opens multiple connections for parallel transfers so doesn’t benefit much, is my understanding)
R2 Custom Domains support up to Http/2.
Workers w/ R2 bindings support up to http/3.
So yea, R2 Custom Domains currently don’t.
R2 Custom Domains use a Cloudflare product, Custom Hostnames/CF for SaaS, which basically hooks the custom domain to their zone (r2.dev) and enforces specific settings from the Custom Hostnames settings and the underlying zone settings, on top of/over your own zone/domain’s settings.
Thank you very much, your answer solved my doubts very well.
It seems that the zones have higher priority in some places (such as alt-svc header and HTTPS DNS record), which causes the browser to be hinted to use QUIC when it actually does not support it. Maybe I should add a rule to remove the alt-svc header and set the HTTPS record manually until QUIC is supported by R2.
Well…I cannot remove alt-svc header without turning off QUIC for the zone. This may cause some QUIC rollback. Maybe it is a bug, I am looking forward to a solution.