Pfsense could do the job also, if you install tinyDNS and increase the cache limit which is 1Mb by default to perhaps 100mb. I'm giving a try right now because my ISP here in mexico city is so damn slow to resolve domains outside the america continent.

cheers.

--
"It is human nature to think wisely and act in an absurd fashion."

"Todo el desorden del mundo proviene de las profesiones mal o mediocremente servidas"