Viktor Dukhovni:
> On Tue, Mar 22, 2016 at 10:28:48AM -0400, Wietse Venema wrote:
>
> > In order to protect the stability of the Postfix SMTP client, I
> > propose a new feature that builds on smtp_tls_policy_maps that
> > allows experimentation with STS and other features.
> >
> > The design is similar to the way that Postfix SMTP server policies
> > build on access maps.
> >
> > 1) An optional smtp_check_tls_policy client in the Postfix SMTP
> > client that speaks TCP or local IPC just like the SMTP server's
> > check_policy feature.
> >
> > /etc/postfix/main.cf:
> > smtp_check_tls_policy = inet:127.0.0.1:12345
>
> Unfortunately, this is not quite sufficient for STS. There are
> two complications:
>
> 1. STS policies are "validated" at time of first use, and
> caching of the policy is only enabled on successful delivery.
> 2. STS domains will likely solicit authentication failure feedback.
>
> So the STS policy service will need to receive success/failure
> reports for deliveries to domains that publish STS policy.
>
> > Is this all paractical, or will we be stuck with C code?
>
> Not yet clear...
What about two requests: the first to look up policy, and the second
to report success/failure status? The second part would require a
few new attributes, because the Postfix SMTP client currently does
not maintain detailed attributes after TLS failure.
Wietse
