I have a home network with 2 Macs and one Linux box. There is a caching DNS nameserver on the Linux box. I would like the Macs to use the caching server, and only if that is inaccessible fall through to external DNS.
Do Macs rotate through all the configured nameservers or try them in order until one works?
Another quirk is that internal DHCP is served by my router (a Linksys WRT54GL), which has room for three nameservers. But if less than three are configured, the blank spots are filled in with whatever the router's external DHCP has provided -- in this case, Comcast's "Domain Helper" DNS breakage, which I don't want (the cache is configured to use Google's public DNS).
Thus, if Macs do round-robin, I need something to put in the other two spots. Is it bad to simply repeat the caching server's IP?