Enabling HTTP3 for a VCL

I’m experimenting with enabling http3 for an (existing) test CDN service, following the instructions in Enabling HTTP/3 for Fastly services
I’ve enable http3 in the VCL config, and activated the TLS config for “HTTP/3 & TLS v1.3 + 0RTT” in the TLS domain activations section. But nevertheless is seems that it’s not possible to establish an http3 connection to the service.

Am I missing something? My understanding is it doesn’t matter about the origin services, the VCL service should terminate the HTTP3 connection?

Hey @PaulRudin :wave:

Since it sounds like you’ve added the relevant configuration to the service, I’m wondering if this is because your DNS records need updating to refer to the “HTTP/3 & TLS v1.3 + 0RTT” configuration that you activated.

See the above example from my own account in which the second TLS configuration (which supports HTTP/3) has different a CNAME and A records to the first one.

Hopefully this helps, otherwise your best bet would be to reach out to support@fastly.com who can take a look at the config and investigate further

So I appear to have 5 different TLS configurations, how do I know which one is relevant? Two of them mention HTTP3.

… or to put it another way, how do we know what the link is between “subscriptions” and “configurations”, since they both have their own page?

OK, I have now got it working by changing the relevant CNAME record at route53.