and IPv6

Following up on a two year old thread, one of my clients just hit this
problem. The failure is not that is not reachable over ipv6
(2605:3100:fffd:100::15). They accept (TCP handshake) the port 443
connection, but the connection then hangs waiting for the TLS handshake.

openssl s_client -connect

openssl s_client -servername -connect

Browsers (at least firefox) see that as a very slow site, and it does
not trigger their happy eyeballs fast failover to ipv4.