TLS doesn't have a fixed port number. Ergo, TLS-ALPN doesn't either. It is the intention of the ALPN spec that you can do tls-alpn-01 on whatever TCP port the

TLS doesn't have a fixed port number. Ergo, TLS-ALPN doesn't either. It is the intention of the ALPN spec that you can do tls-alpn-01 on whatever TCP port the two parties (issuer and recipient) care to use.