Preventing external lookups

[Mark]

Hello,

Running BIND 8.4.1, I loaded a large master zone from a DNS blocklist. The
result? Matches are found very fast, of course. But when BIND cannot find a
match, it still seems to query the root-servers, which can take quite a
while to return a negative response.

So, my question is, can I prevent any external lookups for one specific
zone? External meaning: anything not defined in the zone file itself.

Thanks!

- Mark