Very cool.

A note that might be useful for new users of 8.12:
sendmail 8.12.x and the "double delivery" (first to a local queue,
then to a listener on port 25) means that it's hard to "watch"
deliveries by hand.  "date| Mail -v nobody@example.com" will show
an SMTP connection to localhost.

Sendmail is no longer setuid, so sendmail invoked from the command
line as a user cannot write to the mqueue directory any longer.
This is good.

date | sendmail -v -Am nobody@example.com
will force it to use the connection directly.  As root. 

One of the bigger 8.12 advantages is queue groups:
You can have a queue or group of queues set for mail to, say,
inbound vs. outbound or mail to a partner can go into a special
set of queues.  Mail FROM certain addresses can be put in queues.
Hell, write the right rules and you can have queue groups by hour
of day.

These queue groups can have things like queue runners waiting
and running continuously (useful where inbound should ALWAYS be
up and waiting where outbound mail should get the usual "run a queue
runner every 30 or 60 minutes behavior).  You can nice down queue
runners, etc, etc.  Basically it's easier to tune up sendmail
to get the max performance and throughput.


Additionally, there are several variables introduces and exposed
to the cf rules and you can now enforce that connections to/from
certain domains are using TLS.  This is useful if you want to
be SURE that when you send to "partner.com" or a remote office
of yours that you have TLS running.  Or when using SMTP-AUTH :)

(remote offices actually do better with IPSec as a longer living
connection rather than beating the machines with short SSL sessions).