** DNS **
Starting from FreeBSD 10.0, BIND has been replaced in base
by unbound.  This means that there are no dig and nslookup
utilities for check_dig and check_dns to use.  If you choose
DNS_BASE, check_dig will be built using drill instead of
dig, if you use -A the dig options will generally not work,
check drill(1) for the correct ones, also, timeout and retry
will be ignored, and check_dns won't be installed.  If you
check any other option, the installed dig and nslookup will
be used.

If you run FreeBSD < 10, you can still use the DNS_BIND*
options to have check_dig and check_dns use the newer dig
and nslookup utilities.

If you use REPLACE_BASE with BIND, choose the DNS_BASE option.