looks like you can't install Postfix and BIND together on today's #FreeBSD:

New packages to be INSTALLED:
lmdb: 1.0.2,1 [FreeBSD-ports]
postfix: 3.11.7_1,1 [FreeBSD-ports]

Installed packages to be REMOVED:
bind920: 9.20.29
lmdb0: 0.9.35

#sysadmin