Extras/SwitchingToPostfix. I'm a touch disappointed, I thought it would be a guide on how to update Postfix configurations to match Sendmail. I'd been running Sendmail on FreeBSD for 14 years now, so some of the config changes I've made I just don't remember, if there was a way to check and validate Postfix and see what changes need to be made I'd be more inclined to switch.