Paul Hoffman <paul.hoff...@vpnc.org> wrote: > On May 12, 2015, at 11:40 AM, Simon Josefsson <si...@josefsson.org> wrote: > > > For SMTP, IMAP, POP etc the reason for having both port-based and > > upgrade-based is legacy and historic reasons: back in the days the > > STARTTLS approach wasn't invented, so following HTTP(S) footsteps, new > > ports were allocated for "secure" protocol variants. Modern protocols > > does not have this issue; compare XMPP.
> That's not accurate for SMTP: during discussion of RFC 2487, there was > no alternate port for SMTP-over-TLS. It's also not accurate for IMAP and > POP: both of those got STARTTLS-like extensions "because that's how SMTP > works". My understanding is that the smtps port was allocated, then in a fit of panic the IETF decided that allocating N*M ports (N protocols, M security layers) would be a disaster and cause horrible security layer negotiation problems, so smtps was un-allocated and STARTTLS was invented. (IANA doesn't record when imaps and pops ports were allocated but I think it was before smtps.) Tony. -- f.anthony.n.finch <d...@dotat.at> http://dotat.at/ Southeast Iceland: Variable 4, becoming southeasterly 5 or 6. Moderate or rough. Showers. Good. _______________________________________________ dns-privacy mailing list dns-privacy@ietf.org https://www.ietf.org/mailman/listinfo/dns-privacy
