In contrast, BIND keeps growing, and growing, and growing. BIND has no limits on cache size; it tries to cache every record until the record expires. Under heavy load, BIND will chew up all your physical memory, start thrashing, chew up all your virtual memory, and then commit hara-kiri, if it doesn't dump core first.
I did 968355 random PTR lookups for an Internet survey in December 1999, using alpha versions of dnsfilter and dnscache. The survey finished in 4.5 hours on a Pentium-133. It would have been practically impossible with BIND.
BIND has a server-configuration mechanism, called ``forwarding.'' However, BIND's ``forwarding'' uses recursive queries, which are a disaster for large domains.
The BIND company announced in 1995 that they were going to ``restart'' queries, eliminating this problem. Five years later, they still hadn't succeeded. ``It's too hard,'' says a comment in the BIND code. The BIND internals are too much of a mess.
dnscache doesn't have this problem. It doesn't cut corners in its resolution algorithm.