The default configuration (and compiled in) options for ISC BIND uses
DNSSEC per default which under certain circumstances can result in
huge latencies due to the overhead of trying to validate each lookup,
and everytime. This has now been disabled in the configuration file
(/var/lib/named/etc/named.conf) for performance reasons but can
easily be enabled again. Please have a look at the dnssec-enable
and dnssec-validation configuration options and set the preferred
method there.