Http3 only works on ipv6

[egorka]

strange problem. the site opens perfectly on http3 if you access it using ip6, but stubbornly remains on http2 if you leave only ip4.

in the config I tried different combinations and options that I found on Google:

server {
listen 82.202..:443 quic;# reuseport;
listen 82.202..:443 ssl;

    #listen      [2a00:ab00:1103:*::*]:443 quic reuseport;
    #listen      [2a00:ab00:1103:*::*]:443 ssl;

    http3 on;
    # http3_hq on; ???
    quic_retry on;
    quic_gso on;
    # ssl_early_data on; already in the main config

    # required for browsers to direct them to quic port
    # from location / {
    add_header Alt-Svc 'h3-28=":443"; ma=604800';
    add_header Alt-Svc 'h3=":443"; ma=2592000,h3-29=":443"; ma=2592000';
    add_header x-quic 'h3';
    add_header X-protocol $server_protocol always;
    server_name *.* www.*.*;

instead of asterisks - numbers and domains.

the essence of the problem: on IP6 everything is fine, in chrome you can immediately see h3. Doesn’t work on IP4.

I suspect that somewhere Hestia automatically does something for ip4, but I didn’t find anything

[egorka]

UDP 443 in firewall ))

This is an important step, but not a solution to the problem ((

I tried stopping iptables - it didn’t help

[egorka]

I made different domains, on different IPs, so as not to confuse anything.

I can’t imagine how this is possible, but:

if the domain in the dns only has IP4, then everything works

If the domain has IP4 and IP6 in the dns, then http3 on IP4 does not work for it.

[egorka]

The feature is not related to the panel, Nginx version or ssl library. it’s like this:
if the client has IP6, the domain DNS has IP6, but the IP6 server does not listen, then the browser (Chrome) will not switch to http3