Rick Moen writes:
> One recursive namserver per LAN is obviously better than several on
> grounds of multiple considerations that I won't belabour here.

Is it, really? Significantly?

It eases the load on the root and big-zone TLDs. I've heard that most of
their load is caused by other factors, though, including misconfigured
brokenware and malevolent software, so I'm not sure whether additional load
from correctly caching resolvers really moves their needle.

It eases the load on auth nameserver for zones that don't use load
balancing, if any such zones are big enough to be used by many people on a
LAN, yet small enough to be used infrequently. (If they're big enough to be
used frequently, then the big savings come from caching, and all the shared
cache does can do is improve the hit ratio from ninety-foo per cent to
ninety-bar per cent.)

The DNS packets are small, the network is faster than a decade or two ago,
the load situation has changed with all the load balancing and evilware...
I think the value of shared caching resolvers is shrinking towards zero.

Arnt