I’ve found a very easy way to use local DNS caching on the Mac: simply setup Internet sharing from one device you don’t use, to another you don’t use.

…This local DNS server takes its nameserver addresses from your current Internet configuration (in my case, wireless), so everything is automatically setup to cache DNS from the nameservers you’re actually using.

…Using the Network Preferences Pane, find out what your local Ethernet address is (to use my example; you’ll have to find the IP of the interface you’re sharing from).

…This is especially helpful on connections that drop packets a lot, since I find a great number of the “pauses” in my Internet usage all relate to lagged out DNS lookups.