High performance DNS server configuration?

[John Levine]

>Problem is procmail + postfix with rbl's (zen.spamhaus.org and others).
>
>Really big problem are spam botnet's and some day we can get over 5-6
>million messages per day or even more.
>
>Procmail/postfix is doing every check per msg at localdns (localdns =>
>rbl's) server and average check time is 1-2 sec per message and it's
>too much.

I agree that bind is likely not the best DNS cache for this purpose.
You might look at unbound.

More importantly, at that query volume you should be running a local
copy of rbndnsd and rsync'ing the DNSBLs.

R's,
John