I've included my postconf below. This server only receives mail from
our external relay (and a few other local systems). This configuration
originated from the configuration of that external relay, so some of
it like the postscreen stuff probably isn't necessary.
Also, is always_bcc what some companies use to provide "always on"
email service to their clients/users? In other words, is there a way
to store a copy of the email on one system and allow users to somehow
access that when their primary system is unavailable? Considering
always_bcc stores to a single mbox, some kind of mailbox management
would be necessary?