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

2) Each query is a dump of all relevant SMTP client state, one 
attribute and value per line:

    query:
        attribute_1 = value_1
        attribute_2 = value_2
        ...
        [empty line]

    Q1: What point in time is the call made?

    Q2: What attributes to send? E.g., nexthop, recipient, SMTP_SESSION,
    SMTP_ITERATOR, what else?

3) The reply is exactly the same as with smtp_tls_policy_maps. The
rationale for this is to simplify implementation, user interface, and
documentation (less code to write and fewer new things to learn).

    reply:
        policy = [same stuff as in smtp_tls_policy_maps lookup result]
        [empty line]

Is this all paractical, or will we be stuck with C code?

        Wietse

Reply via email to