how to protect name servers against cache corruption

BIND 4.9.6 and 8.1.1 are immune to all known attacks, including the one

[ splice ]

I know of attacks we are not immune to, which cannot be stopped without

Um. I hate to play semantic games, but if you know of attacks that BIND
8.1.1 is not immune to, then BIND 8.1.1 is not immune to all known

Since this is not a security list, I'll refrain from (rhetorically)
informing you that history doesn't back up your assertion of the existence
of "holes that only the good guys know".

Oops. Sorry about that.

Thanks for clearing this up!