How not to design a wire protocol

[Daniel Franke]

On Tue, Mar 5, 2019 at 1:52 PM Eric S. Raymond <esr at thyrsus.com> wrote:
> If you end up going with a non-123 port number, I requst that the RFC
> allow use on other ports when and if ALPN is available and specify
> the ALPN tag to be used.

The spec already mandates that ALPN always be used and allocates a tag
with IANA.

> I disagree.  New firewall holes are difficult, practically if not
> theoretically.

tcp/123 is already a new firewall hole. If you want to work around
unchangeable firewall rules you probably have to use 443 (and again
rely on ALPN).