dan bernstein (của qmail fame) có một trang dành riêng cho việc chọn tên dns cho mạng cục bộ ( http://cr.yp.to/djbdns/dot-local.html ):
It isn't easy to choose a safe top-level local name. The global root
operators add new top-level names every once in a while: for example,
.info was added in 2001, so people using .info as a local name were
unable to reach global .info sites. Software authors sometimes set 
aside top-level names; for example, I'm told that Mac OS 9 does something
weird with .local, so it can't access local names in .local. Here are 
some reasonable choices of top-level local names:
 .0       (good for machine-specific names)
 .1
 .2
 .3       (good for department-specific names)
 .4
 .5
 .6       (good for corporation-specific names)
 .7
 .8
 .9
 .internal