Postfix 2.7-20091104-nonprod introduces a "speed adjust" feature
that reduces the number of before-queue filter processes, without
reducing the number of before-filter SMTP server processes.
This addresses a concern of people in Europe who want to reject
all bad mail with a before-queue filter, instead of having to use
an after-queue filter and having to discard mail (which is illegal)
or having to bounce mail (which violates good network citizenship).
With "smtpd_proxy_options = speed_adjust", the SMTP server will
receive the entire message before it connects to a content filter.
For more information see the RELEASE_NOTES.
This is released as a non-production release first, because I took
the opportunity to clean up the existing before-queue filter code.
Wietse
