Hal: dnsmasq is the dns cache prog.

[Brian Kelsay]

http://thekelleys.org.uk/dnsmasq/doc.html

I couldn't remember last night, but here it is.  Apparently most of the Linux-based firewalls use 
this package.  Also of note is that "from version 0.95 the cache honours time-to-live information 
and removes old records as they expire."

Also, to save you some reading:
"Supported platforms include Linux (with glibc and uclibc), *BSD and Mac OS X. Dnsmasq is included 
in at least the following Linux distributions: Gentoo, Debian, Slackware, Suse, Smoothwall, IP-Cop, 
floppyfw, Firebox, LEAF, Freesco, CoyoteLinux and Clarkconnect. It is also available as a FreeBSD 
port and is used in Linksys wireless routers."

bill_c uses m0n0wall, but it is based on freeBSD and I don't know what it uses.  Apparently it too 
uses dnsmasq  http://m0n0.ch/wall/docbook/intro-features.html  So our group should be pretty much 
covered.

Brian Kelsay