So, you want http3?

This is a quick & dirty howto.

1. Open port 443/udp to your nginx instance
2. Put http3 on; in nginx.conf. (and additional http2 on; but not required)
3. Add Listen 443 quic; to your ssl interface
4. Put the following in your serverblock (in location /) add_header Alt-Svc 'h3=":443"';   # Advertise that HTTP/3 is available
5. Check with nginx -t if everything is alright
6. Restart nginx
7. Check with curl or an online http3 checker

Please note, the nginx from http://deb.myguard.nl is compiled with OpenSSL3.0.x+quic, you should install the custom OpenSSL from deb.myguard.nl as well if not done automaticly.