[Pymilter] Discovering MTA interface port

[Stuart D Gathman]

It turns out that at least one problem could be neatly solved if only an
{if_port} macro were available in the connect callback.  It is only 2 or
3 lines of code to add it, but then there is the logistics of
maintaining a custom version of sendmail. 

The problem is that we track reputation by IP as well as domain.  Often,
IPs of public networks at airports, hotels, and such are banned (from
sending email) because of frequent abuse.  When a salesman travels, he
needs to send email from said airports and hotels - which should not be
a problem since he uses SMTP AUTH with his smartphone or tablet.  Except
that when I REJECT the banned IP in connect, he never gets a chance to
authenticate. 

Rather than delay the rejection until MAIL FROM, I would rather skip
banned IP checking altogether for connections on port 587 - which only
allows authenticated connections.  But milters don't seem to have any
way to get that information.

Does anyone have any ideas besides patching sendmail?  I went to
sendmail.org, but couldn't figure out where to send feature requests
(probably by design for such a popular product).